Package org.eclipse.jdt.core.search

Source Code of org.eclipse.jdt.core.search.SearchPattern

/*******************************************************************************
* Copyright (c) 2000, 2010 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
*     IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.core.search;

import java.io.IOException;

import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.jdt.core.*;
import org.eclipse.jdt.core.compiler.*;
import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
import org.eclipse.jdt.internal.compiler.env.AccessRuleSet;
import org.eclipse.jdt.internal.compiler.parser.Scanner;
import org.eclipse.jdt.internal.compiler.parser.ScannerHelper;
import org.eclipse.jdt.internal.compiler.parser.TerminalTokens;
import org.eclipse.jdt.internal.core.LocalVariable;
import org.eclipse.jdt.internal.core.index.EntryResult;
import org.eclipse.jdt.internal.core.index.Index;
import org.eclipse.jdt.internal.core.search.HierarchyScope;
import org.eclipse.jdt.internal.core.search.IndexQueryRequestor;
import org.eclipse.jdt.internal.core.search.JavaSearchScope;
import org.eclipse.jdt.internal.core.search.StringOperation;
import org.eclipse.jdt.internal.core.search.indexing.IIndexConstants;
import org.eclipse.jdt.internal.core.search.matching.*;


/**
* A search pattern defines how search results are found. Use <code>SearchPattern.createPattern</code>
* to create a search pattern.
* <p>
* Search patterns are used during the search phase to decode index entries that were added during the indexing phase
* (see {@link SearchDocument#addIndexEntry(char[], char[])}). When an index is queried, the
* index categories and keys to consider are retrieved from the search pattern using {@link #getIndexCategories()} and
* {@link #getIndexKey()}, as well as the match rule (see {@link #getMatchRule()}). A blank pattern is
* then created (see {@link #getBlankPattern()}). This blank pattern is used as a record as follows.
* For each index entry in the given index categories and that starts with the given key, the blank pattern is fed using
* {@link #decodeIndexKey(char[])}. The original pattern is then asked if it matches the decoded key using
* {@link #matchesDecodedKey(SearchPattern)}. If it matches, a search document is created for this index entry
* using {@link SearchParticipant#getDocument(String)}.
*
* </p><p>
* This class is intended to be sub-classed by clients. A default behavior is provided for each of the methods above, that
* clients can override if they wish.
* </p>
* @see #createPattern(org.eclipse.jdt.core.IJavaElement, int)
* @see #createPattern(String, int, int, int)
* @since 3.0
*/
public abstract class SearchPattern {

  // Rules for pattern matching: (exact, prefix, pattern) [ | case sensitive]
  /**
   * Match rule: The search pattern matches exactly the search result,
   * that is, the source of the search result equals the search pattern.
   */
  public static final int R_EXACT_MATCH = 0;

  /**
   * Match rule: The search pattern is a prefix of the search result.
   */
  public static final int R_PREFIX_MATCH = 0x0001;

  /**
   * Match rule: The search pattern contains one or more wild cards ('*' or '?').
   * A '*' wild-card can replace 0 or more characters in the search result.
   * A '?' wild-card replaces exactly 1 character in the search result.
   */
  public static final int R_PATTERN_MATCH = 0x0002;

  /**
   * Match rule: The search pattern contains a regular expression.
   */
  public static final int R_REGEXP_MATCH = 0x0004;

  /**
   * Match rule: The search pattern matches the search result only if cases are the same.
   * Can be combined to previous rules, e.g. {@link #R_EXACT_MATCH} | {@link #R_CASE_SENSITIVE}
   */
  public static final int R_CASE_SENSITIVE = 0x0008;

  /**
   * Match rule: The search pattern matches search results as raw/parameterized types/methods with same erasure.
   * This mode has no effect on other java elements search.<br>
   * Type search example:
   *   <ul>
   *   <li>pattern: <code>List&lt;Exception&gt;</code></li>
   *   <li>match: <code>List&lt;Object&gt;</code></li>
   *   </ul>
   * Method search example:
   *   <ul>
   *   <li>declaration: <code>&lt;T&gt;foo(T t)</code></li>
   *   <li>pattern: <code>&lt;Exception&gt;foo(new Exception())</code></li>
   *   <li>match: <code>&lt;Object&gt;foo(new Object())</code></li>
   *   </ul>
   * Can be combined to all other match rules, e.g. {@link #R_CASE_SENSITIVE} | {@link #R_ERASURE_MATCH}
   * This rule is not activated by default, so raw types or parameterized types with same erasure will not be found
   * for pattern List&lt;String&gt;,
   * Note that with this pattern, the match selection will be only on the erasure even for parameterized types.
   * @since 3.1
   */
  public static final int R_ERASURE_MATCH = 0x0010;

  /**
   * Match rule: The search pattern matches search results as raw/parameterized types/methods with equivalent type parameters.
   * This mode has no effect on other java elements search.<br>
   * Type search example:
   * <ul>
   *   <li>pattern: <code>List&lt;Exception&gt;</code></li>
   *   <li>match:
   *     <ul>
   *     <li><code>List&lt;? extends Throwable&gt;</code></li>
   *     <li><code>List&lt;? super RuntimeException&gt;</code></li>
   *     <li><code>List&lt;?&gt;</code></li>
   *      </ul>
   *   </li>
   *   </ul>
   * Method search example:
   *   <ul>
   *   <li>declaration: <code>&lt;T&gt;foo(T t)</code></li>
   *   <li>pattern: <code>&lt;Exception&gt;foo(new Exception())</code></li>
   *   <li>match:
   *     <ul>
   *     <li><code>&lt;? extends Throwable&gt;foo(new Exception())</code></li>
   *     <li><code>&lt;? super RuntimeException&gt;foo(new Exception())</code></li>
   *     <li><code>foo(new Exception())</code></li>
   *      </ul>
   *   </ul>
   * Can be combined to all other match rules, e.g. {@link #R_CASE_SENSITIVE} | {@link #R_EQUIVALENT_MATCH}
   * This rule is not activated by default, so raw types or equivalent parameterized types will not be found
   * for pattern List&lt;String&gt;,
   * This mode is overridden by {@link  #R_ERASURE_MATCH} as erasure matches obviously include equivalent ones.
   * That means that pattern with rule set to {@link #R_EQUIVALENT_MATCH} | {@link  #R_ERASURE_MATCH}
   * will return same results than rule only set with {@link  #R_ERASURE_MATCH}.
   * @since 3.1
   */
  public static final int R_EQUIVALENT_MATCH = 0x0020;

  /**
   * Match rule: The search pattern matches exactly the search result,
   * that is, the source of the search result equals the search pattern.
   * @since 3.1
   */
  public static final int R_FULL_MATCH = 0x0040;

  /**
   * Match rule: The search pattern contains a Camel Case expression.
   * <p>
   * Examples:
   * <ul>
   *   <li>'NPE' type string pattern will match
   *     'NullPointerException' and 'NoPermissionException' types,</li>
   *   <li>'NuPoEx' type string pattern will only match
   *     'NullPointerException' type.</li>
   * </ul>
   *
   * This rule is not intended to be combined with any other match rule. In case
   * of other match rule flags are combined with this one, then match rule validation
   * will return a modified rule in order to perform a better appropriate search request
   * (see {@link #validateMatchRule(String, int)} for more details).
   * <p>
   * @see #camelCaseMatch(String, String) for a detailed explanation of Camel
   *   Case matching.
   *
   * @since 3.2
   */
  public static final int R_CAMELCASE_MATCH = 0x0080;

  /**
   * Match rule: The search pattern contains a Camel Case expression with
   * a strict expected number of parts.
   * <br>
   * Examples:
   * <ul>
   *   <li>'HM' type string pattern will match 'HashMap' and 'HtmlMapper' types,
   *     but not 'HashMapEntry'
   *   </li>
   *   <li>'HMap' type string pattern will still match previous 'HashMap' and
   *     'HtmlMapper' types, but not 'HighMagnitude'
   *   </li>
   * </ul>
   *
   * This rule is not intended to be combined with any other match rule. In case
   * of other match rule flags are combined with this one, then match rule validation
   * will return a modified rule in order to perform a better appropriate search request
   * (see {@link #validateMatchRule(String, int)} for more details).
   * <p>
   * @see CharOperation#camelCaseMatch(char[], char[], boolean) for a detailed
   * explanation of Camel Case matching.
   *<p>
   * @since 3.4
   */
  public static final int R_CAMELCASE_SAME_PART_COUNT_MATCH = 0x0100;

  private static final int MODE_MASK = R_EXACT_MATCH
    | R_PREFIX_MATCH
    | R_PATTERN_MATCH
    | R_REGEXP_MATCH
    | R_CAMELCASE_MATCH
    | R_CAMELCASE_SAME_PART_COUNT_MATCH;

  private int matchRule;

  /**
   * The focus element (used for reference patterns)
   * @noreference This field is not intended to be referenced by clients.
   */
  public IJavaElement focus;

  /**
   * @noreference This field is not intended to be referenced by clients.
   */
  public int kind;
 
  /**
   * @noreference This field is not intended to be referenced by clients.
   */
  public boolean mustResolve = true;
 
/**
* Creates a search pattern with the rule to apply for matching index keys.
* It can be exact match, prefix match, pattern match or regexp match.
* Rule can also be combined with a case sensitivity flag.
*
* @param matchRule one of following match rule
*   <ul>
*     <li>{@link #R_EXACT_MATCH}</li>
*     <li>{@link #R_PREFIX_MATCH}</li>
*     <li>{@link #R_PATTERN_MATCH}</li>
*     <li>{@link #R_REGEXP_MATCH}</li>
*     <li>{@link #R_CAMELCASE_MATCH}</li>
*     <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}</li>
*   </ul>
*   which may be also combined with one of following flag:
*   <ul>
*     <li>{@link #R_CASE_SENSITIVE}</li>
*     <li>{@link #R_ERASURE_MATCH}</li>
*     <li>{@link #R_EQUIVALENT_MATCH}</li>
*   </ul>
*    For example,
*    <ul>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_CASE_SENSITIVE}: if an exact
*        and case sensitive match is requested,</li>
*      <li>{@link #R_PREFIX_MATCH} if a case insensitive prefix match is requested</li>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_ERASURE_MATCH}: if a case
*        insensitive and erasure match is requested.</li>
*    </ul>
*   Note that {@link #R_ERASURE_MATCH} or {@link #R_EQUIVALENT_MATCH} has no effect
*   on non-generic types/methods search.
*   <p>
*   Note also that default behavior for generic types/methods search is to find exact matches.
*/
public SearchPattern(int matchRule) {
  this.matchRule = matchRule;
  // Set full match implicit mode
  if ((matchRule & (R_EQUIVALENT_MATCH | R_ERASURE_MATCH )) == 0) {
    this.matchRule |= R_FULL_MATCH;
  }
  // reset other incompatible flags
  if ((matchRule & R_CAMELCASE_MATCH) != 0) {
    this.matchRule &= ~R_CAMELCASE_SAME_PART_COUNT_MATCH;
    this.matchRule &= ~R_PREFIX_MATCH;
  } else if ((matchRule & R_CAMELCASE_SAME_PART_COUNT_MATCH) != 0) {
    this.matchRule &= ~R_PREFIX_MATCH;
  }
}
/**
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public void acceptMatch(String relativePath, String containerPath, char separator, SearchPattern pattern, IndexQueryRequestor requestor, SearchParticipant participant, IJavaSearchScope scope) {
  acceptMatch(relativePath, containerPath, separator, pattern, requestor, participant, scope, null);
}
/**
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public void acceptMatch(String relativePath, String containerPath, char separator, SearchPattern pattern, IndexQueryRequestor requestor, SearchParticipant participant, IJavaSearchScope scope, IProgressMonitor monitor) {

  if (scope instanceof JavaSearchScope) {
    JavaSearchScope javaSearchScope = (JavaSearchScope) scope;
    // Get document path access restriction from java search scope
    // Note that requestor has to verify if needed whether the document violates the access restriction or not
    AccessRuleSet access = javaSearchScope.getAccessRuleSet(relativePath, containerPath);
    if (access != JavaSearchScope.NOT_ENCLOSED) { // scope encloses the document path
      StringBuffer documentPath = new StringBuffer(containerPath.length() + 1 + relativePath.length());
      documentPath.append(containerPath);
      documentPath.append(separator);
      documentPath.append(relativePath);
      if (!requestor.acceptIndexMatch(documentPath.toString(), pattern, participant, access))
        throw new OperationCanceledException();
    }
  } else {
    StringBuffer buffer = new StringBuffer(containerPath.length() + 1 + relativePath.length());
    buffer.append(containerPath);
    buffer.append(separator);
    buffer.append(relativePath);
    String documentPath = buffer.toString();
    boolean encloses = (scope instanceof HierarchyScope) ? ((HierarchyScope)scope).encloses(documentPath, monitor)
              : scope.encloses(documentPath);
    if (encloses)
      if (!requestor.acceptIndexMatch(documentPath, pattern, participant, null))
        throw new OperationCanceledException();

  }
}
/**
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public SearchPattern currentPattern() {
  return this;
}
/**
* Answers true if the pattern matches the given name using CamelCase rules, or
* false otherwise. char[] CamelCase matching does NOT accept explicit wild-cards
* '*' and '?' and is inherently case sensitive.
* <p>
* CamelCase denotes the convention of writing compound names without spaces,
* and capitalizing every term. This function recognizes both upper and lower
* CamelCase, depending whether the leading character is capitalized or not.
* The leading part of an upper CamelCase pattern is assumed to contain a
* sequence of capitals which are appearing in the matching name; e.g. 'NPE' will
* match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern
* uses a lowercase first character. In Java, type names follow the upper
* CamelCase convention, whereas method or field names follow the lower
* CamelCase convention.
* <p>
* The pattern may contain lowercase characters, which will be matched in a case
* sensitive way. These characters must appear in sequence in the name.
* For instance, 'NPExcep' will match 'NullPointerException', but not
* 'NullPointerExCEPTION' or 'NuPoEx' will match 'NullPointerException', but not
* 'NoPointerException'.
* <p>
* Digit characters are treated in a special way. They can be used in the pattern
* but are not always considered as leading character. For instance, both
* 'UTF16DSS' and 'UTFDSS' patterns will match 'UTF16DocumentScannerSupport'.
* <p>
* Using this method allows matching names to have more parts than the specified
* pattern (see {@link #camelCaseMatch(String, String, boolean)}).<br>
* For instance, 'HM' , 'HaMa' and  'HMap' patterns will match 'HashMap',
* 'HatMapper' <b>and also</b> 'HashMapEntry'.
* <p>
* <pre>
* Examples:
* <ol><li>  pattern = "NPE"
*  name = NullPointerException / NoPermissionException
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  name = NullPointerException
*  result => true</li>
* <li>  pattern = "npe"
*  name = NullPointerException
*  result => false</li>
* <li>  pattern = "IPL3"
*  name = "IPerspectiveListener3"
*  result => true</li>
* <li>  pattern = "HM"
*  name = "HashMapEntry"
*  result => true</li>
* <li>  pattern = "HMap"
*  name = "HatMapper"
*  result => true</li>
* </ol></pre>
*
* @see #camelCaseMatch(String, int, int, String, int, int, boolean) for algorithm
* implementation
*
* @param pattern the given pattern
* @param name the given name
* @return true if the pattern matches the given name, false otherwise
* @since 3.2
*/
public static final boolean camelCaseMatch(String pattern, String name) {
  if (pattern == null)
    return true; // null pattern is equivalent to '*'
  if (name == null)
    return false; // null name cannot match

  return camelCaseMatch(pattern, 0, pattern.length(), name, 0, name.length(), false/*not the same count of parts*/);
}

/**
* Answers true if the pattern matches the given name using CamelCase rules, or
* false otherwise. char[] CamelCase matching does NOT accept explicit wild-cards
* '*' and '?' and is inherently case sensitive.
* <p>
* CamelCase denotes the convention of writing compound names without spaces,
* and capitalizing every term. This function recognizes both upper and lower
* CamelCase, depending whether the leading character is capitalized or not.
* The leading part of an upper CamelCase pattern is assumed to contain a
* sequence of capitals which are appearing in the matching name; e.g. 'NPE' will
* match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern
* uses a lowercase first character. In Java, type names follow the upper
* CamelCase convention, whereas method or field names follow the lower
* CamelCase convention.
* <p>
* The pattern may contain lowercase characters, which will be matched in a case
* sensitive way. These characters must appear in sequence in the name.
* For instance, 'NPExcep' will match 'NullPointerException', but not
* 'NullPointerExCEPTION' or 'NuPoEx' will match 'NullPointerException', but not
* 'NoPointerException'.
* <p>
* Digit characters are treated in a special way. They can be used in the pattern
* but are not always considered as leading character. For instance, both
* 'UTF16DSS' and 'UTFDSS' patterns will match 'UTF16DocumentScannerSupport'.
* <p>
* CamelCase can be restricted to match only the same count of parts. When this
* restriction is specified the given pattern and the given name must have <b>exactly</b>
* the same number of parts (i.e. the same number of uppercase characters).<br>
* For instance, 'HM' , 'HaMa' and  'HMap' patterns will match 'HashMap' and
* 'HatMapper' <b>but not</b> 'HashMapEntry'.
* <p>
* <pre>
* Examples:
* <ol><li>  pattern = "NPE"
*  name = NullPointerException / NoPermissionException
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  name = NullPointerException
*  result => true</li>
* <li>  pattern = "npe"
*  name = NullPointerException
*  result => false</li>
* <li>  pattern = "IPL3"
*  name = "IPerspectiveListener3"
*  result => true</li>
* <li>  pattern = "HM"
*  name = "HashMapEntry"
*  result => (samePartCount == false)</li>
* </ol></pre>
*
* @see #camelCaseMatch(String, int, int, String, int, int, boolean) for algorithm
*   implementation
*
* @param pattern the given pattern
* @param name the given name
* @param samePartCount flag telling whether the pattern and the name should
*   have the same count of parts or not.<br>
*   &nbsp;&nbsp;For example:
*   <ul>
*     <li>'HM' type string pattern will match 'HashMap' and 'HtmlMapper' types,
*         but not 'HashMapEntry'</li>
*     <li>'HMap' type string pattern will still match previous 'HashMap' and
*         'HtmlMapper' types, but not 'HighMagnitude'</li>
*   </ul>
* @return true if the pattern matches the given name, false otherwise
* @since 3.4
*/
public static final boolean camelCaseMatch(String pattern, String name, boolean samePartCount) {
  if (pattern == null)
    return true; // null pattern is equivalent to '*'
  if (name == null)
    return false; // null name cannot match

  return camelCaseMatch(pattern, 0, pattern.length(), name, 0, name.length(), samePartCount);
}

/**
* Answers true if a sub-pattern matches the sub-part of the given name using
* CamelCase rules, or false otherwise.  char[] CamelCase matching does NOT
* accept explicit wild-cards '*' and '?' and is inherently case sensitive.
* Can match only subset of name/pattern, considering end positions as non-inclusive.
* The sub-pattern is defined by the patternStart and patternEnd positions.
* <p>
* CamelCase denotes the convention of writing compound names without spaces,
* and capitalizing every term. This function recognizes both upper and lower
* CamelCase, depending whether the leading character is capitalized or not.
* The leading part of an upper CamelCase pattern is assumed to contain a
* sequence of capitals which are appearing in the matching name; e.g. 'NPE' will
* match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern
* uses a lowercase first character. In Java, type names follow the upper
* CamelCase convention, whereas method or field names follow the lower
* CamelCase convention.
* <p>
* The pattern may contain lowercase characters, which will be matched in a case
* sensitive way. These characters must appear in sequence in the name.
* For instance, 'NPExcep' will match 'NullPointerException', but not
* 'NullPointerExCEPTION' or 'NuPoEx' will match 'NullPointerException', but not
* 'NoPointerException'.
* <p>
* Digit characters are treated in a special way. They can be used in the pattern
* but are not always considered as leading character. For instance, both
* 'UTF16DSS' and 'UTFDSS' patterns will match 'UTF16DocumentScannerSupport'.
* <p>
* Digit characters are treated in a special way. They can be used in the pattern
* but are not always considered as leading character. For instance, both
* 'UTF16DSS' and 'UTFDSS' patterns will match 'UTF16DocumentScannerSupport'.
* <p>
* Using this method allows matching names to have more parts than the specified
* pattern (see {@link #camelCaseMatch(String, int, int, String, int, int, boolean)}).<br>
* For instance, 'HM' , 'HaMa' and  'HMap' patterns will match 'HashMap',
* 'HatMapper' <b>and also</b> 'HashMapEntry'.
* <p>
* <pre>Examples:<ol>
* <li>  pattern = "NPE"
*  patternStart = 0
*  patternEnd = 3
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => true</li>
* <li>  pattern = "NPE"
*  patternStart = 0
*  patternEnd = 3
*  name = NoPermissionException
*  nameStart = 0
*  nameEnd = 21
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  patternStart = 0
*  patternEnd = 6
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  patternStart = 0
*  patternEnd = 6
*  name = NoPermissionException
*  nameStart = 0
*  nameEnd = 21
*  result => false</li>
* <li>  pattern = "npe"
*  patternStart = 0
*  patternEnd = 3
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => false</li>
* <li>  pattern = "IPL3"
*  patternStart = 0
*  patternEnd = 3
*  name = "IPerspectiveListener3"
*  nameStart = 0
*  nameEnd = 21
*  result => true</li>
* <li>  pattern = "HM"
*  patternStart = 0
*  patternEnd = 2
*  name = "HashMapEntry"
*  nameStart = 0
*  nameEnd = 12
*  result => true</li>
* <li>  pattern = "HMap"
*  patternStart = 0
*  patternEnd = 4
*  name = "HatMapper"
*  nameStart = 0
*  nameEnd = 9
*  result => true</li>
* </ol></pre>
*
* @param pattern the given pattern
* @param patternStart the start index of the pattern, inclusive
* @param patternEnd the end index of the pattern, exclusive
* @param name the given name
* @param nameStart the start index of the name, inclusive
* @param nameEnd the end index of the name, exclusive
* @return true if a sub-pattern matches the sub-part of the given name, false otherwise
* @since 3.2
*/
public static final boolean camelCaseMatch(String pattern, int patternStart, int patternEnd, String name, int nameStart, int nameEnd) {
  return camelCaseMatch(pattern, patternStart, patternEnd, name, nameStart, nameEnd, false/*not the same count of parts*/);
}

/**
* Answers true if a sub-pattern matches the sub-part of the given name using
* CamelCase rules, or false otherwise.  char[] CamelCase matching does NOT
* accept explicit wild-cards '*' and '?' and is inherently case sensitive.
* Can match only subset of name/pattern, considering end positions as
* non-inclusive. The sub-pattern is defined by the patternStart and patternEnd
* positions.
* <p>
* CamelCase denotes the convention of writing compound names without spaces,
* and capitalizing every term. This function recognizes both upper and lower
* CamelCase, depending whether the leading character is capitalized or not.
* The leading part of an upper CamelCase pattern is assumed to contain
* a sequence of capitals which are appearing in the matching name; e.g. 'NPE' will
* match 'NullPointerException', but not 'NewPerfData'. A lower CamelCase pattern
* uses a lowercase first character. In Java, type names follow the upper
* CamelCase convention, whereas method or field names follow the lower
* CamelCase convention.
* <p>
* The pattern may contain lowercase characters, which will be matched in a case
* sensitive way. These characters must appear in sequence in the name.
* For instance, 'NPExcep' will match 'NullPointerException', but not
* 'NullPointerExCEPTION' or 'NuPoEx' will match 'NullPointerException', but not
* 'NoPointerException'.
* <p>
* Digit characters are treated in a special way. They can be used in the pattern
* but are not always considered as leading character. For instance, both
* 'UTF16DSS' and 'UTFDSS' patterns will match 'UTF16DocumentScannerSupport'.
* <p>
* CamelCase can be restricted to match only the same count of parts. When this
* restriction is specified the given pattern and the given name must have <b>exactly</b>
* the same number of parts (i.e. the same number of uppercase characters).<br>
* For instance, 'HM' , 'HaMa' and  'HMap' patterns will match 'HashMap' and
* 'HatMapper' <b>but not</b> 'HashMapEntry'.
* <p>
* <pre>Examples:<ol>
* <li>  pattern = "NPE"
*  patternStart = 0
*  patternEnd = 3
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => true</li>
* <li>  pattern = "NPE"
*  patternStart = 0
*  patternEnd = 3
*  name = NoPermissionException
*  nameStart = 0
*  nameEnd = 21
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  patternStart = 0
*  patternEnd = 6
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => true</li>
* <li>  pattern = "NuPoEx"
*  patternStart = 0
*  patternEnd = 6
*  name = NoPermissionException
*  nameStart = 0
*  nameEnd = 21
*  result => false</li>
* <li>  pattern = "npe"
*  patternStart = 0
*  patternEnd = 3
*  name = NullPointerException
*  nameStart = 0
*  nameEnd = 20
*  result => false</li>
* <li>  pattern = "IPL3"
*  patternStart = 0
*  patternEnd = 3
*  name = "IPerspectiveListener3"
*  nameStart = 0
*  nameEnd = 21
*  result => true</li>
* <li>  pattern = "HM"
*  patternStart = 0
*  patternEnd = 2
*  name = "HashMapEntry"
*  nameStart = 0
*  nameEnd = 12
*  result => (samePartCount == false)</li>
* </ol></pre>
*
* @see CharOperation#camelCaseMatch(char[], int, int, char[], int, int, boolean)
*   from which algorithm implementation has been entirely copied.
*
* @param pattern the given pattern
* @param patternStart the start index of the pattern, inclusive
* @param patternEnd the end index of the pattern, exclusive
* @param name the given name
* @param nameStart the start index of the name, inclusive
* @param nameEnd the end index of the name, exclusive
* @param samePartCount flag telling whether the pattern and the name should
*   have the same count of parts or not.<br>
*   &nbsp;&nbsp;For example:
*   <ul>
*     <li>'HM' type string pattern will match 'HashMap' and 'HtmlMapper' types,
*         but not 'HashMapEntry'</li>
*     <li>'HMap' type string pattern will still match previous 'HashMap' and
*         'HtmlMapper' types, but not 'HighMagnitude'</li>
*   </ul>
* @return true if a sub-pattern matches the sub-part of the given name, false otherwise
* @since 3.4
*/
public static final boolean camelCaseMatch(String pattern, int patternStart, int patternEnd, String name, int nameStart, int nameEnd, boolean samePartCount) {
  return StringOperation.getCamelCaseMatchingRegions(pattern, patternStart, patternEnd, name, nameStart, nameEnd, samePartCount) != null;
}

/**
* Answers all the regions in a given name matching a given pattern using
* a specified match rule.
* </p><p>
* Each of these regions is made of its starting index and its length in the given
* name. They are all concatenated in a single array of <code>int</code>
* which therefore always has an even length.
* </p><p>
* All returned regions are disjointed from each other. That means that the end
* of a region is always different than the start of the following one.<br>
* For example, if two regions are returned:<br>
* <code>{ start1, length1, start2, length2 }</code><br>
* then <code>start1+length1</code> will always be smaller than
* <code>start2</code>.
* </p><p>
* The possible comparison rules between the name and the pattern are:
* <ul>
* <li>{@link #R_EXACT_MATCH exact matching}</li>
* <li>{@link #R_PREFIX_MATCH prefix matching}</li>
* <li>{@link #R_PATTERN_MATCH pattern matching}</li>
* <li>{@link #R_CAMELCASE_MATCH camel case matching}</li>
* <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH camel case matching with same parts count}</li>
* </ul>
* Each of these rules may be combined with the
* {@link #R_CASE_SENSITIVE case sensitive flag} if the match comparison
* should respect the case.
* <pre>
* Examples:
* <ol><li>  pattern = "NPE"
*  name = NullPointerException / NoPermissionException
*  matchRule = {@link #R_CAMELCASE_MATCH}
*  result:  { 0, 1, 4, 1, 11, 1 } / { 0, 1, 2, 1, 12, 1 } </li>
* <li>  pattern = "NuPoEx"
*  name = NullPointerException
*  matchRule = {@link #R_CAMELCASE_MATCH}
*  result:  { 0, 2, 4, 2, 11, 2 }</li>
* <li>  pattern = "IPL3"
*  name = "IPerspectiveListener3"
*  matchRule = {@link #R_CAMELCASE_MATCH}
*  result:  { 0, 2, 12, 1, 20, 1 }</li>
* <li>  pattern = "HashME"
*  name = "HashMapEntry"
*  matchRule = {@link #R_CAMELCASE_MATCH}
*  result:  { 0, 5, 7, 1 }</li>
* <li>  pattern = "N???Po*Ex?eption"
*  name = NullPointerException
*  matchRule = {@link #R_PATTERN_MATCH} | {@link #R_CASE_SENSITIVE}
*  result:  { 0, 1, 4, 2, 11, 2, 14, 6 }</li>
* <li>  pattern = "Ha*M*ent*"
*  name = "HashMapEntry"
*  matchRule = {@link #R_PATTERN_MATCH}
*  result:  { 0, 2, 4, 1, 7, 3 }</li>
* </ol></pre>
*
* @see #camelCaseMatch(String, String, boolean) for more details on the
*   camel case behavior
* @see CharOperation#match(char[], char[], boolean) for more details on the
*   pattern match behavior
*
* @param pattern the given pattern. If <code>null</code>,
*     then an empty region (<code>new int[0]</code>) will be returned
*     showing that the name matches the pattern but no common
*     character has been found.
* @param name the given name
* @param matchRule the rule to apply for the comparison.<br>
*     The following values are accepted:
*     <ul>
*         <li>{@link #R_EXACT_MATCH}</li>
*         <li>{@link #R_PREFIX_MATCH}</li>
*         <li>{@link #R_PATTERN_MATCH}</li>
*         <li>{@link #R_CAMELCASE_MATCH}</li>
*         <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}</li>
*     </ul>
*     <p>
*     Each of these valid values may be also combined with
*     the {@link #R_CASE_SENSITIVE} flag.
*     </p>
*     Some examples:
*     <ul>
*         <li>{@link #R_EXACT_MATCH} | {@link #R_CASE_SENSITIVE}:
*                 if an exact case sensitive match is expected,</li>
*         <li>{@link #R_PREFIX_MATCH}:
*                 if a case insensitive prefix match is expected,</li>
*         <li>{@link #R_CAMELCASE_MATCH}:
*                 if a case insensitive camel case match is expected,</li>
*         <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}
*                 | {@link #R_CASE_SENSITIVE}:
*                 if a case sensitive camel case with same parts count match
*                 is expected,</li>
*         <li>etc.</li>
*     </ul>
* @return an array of <code>int</code> having two slots per returned
*     regions (the first one is the region starting index and the second one
*     is the region length or <code>null</code> if the given name does not
*     match the given pattern).
*     <p>
*     The returned regions may be empty (<code>new int[0]</code>) if the
*     pattern is <code>null</code> (whatever the match rule is). The returned
*     regions will also be empty if the pattern is only made of <code>'?'</code>
*     and/or <code>'*'</code> character(s) (e.g. <code>'*'</code>,
*     <code>'?*'</code>, <code>'???'</code>, etc.) when using a pattern
*     match rule.
*     </p>
*
* @since 3.5
*/
public static final int[] getMatchingRegions(String pattern, String name, int matchRule) {
  if (name == null) return null;
  final int nameLength = name.length();
  if (pattern == null) {
    return new int[] { 0, nameLength };
  }
  final int patternLength = pattern.length();
  boolean countMatch = false;
  switch (matchRule) {
    case SearchPattern.R_EXACT_MATCH:
      if (patternLength == nameLength && pattern.equalsIgnoreCase(name)) {
        return new int[] { 0, patternLength };
      }
      break;
    case SearchPattern.R_EXACT_MATCH | SearchPattern.R_CASE_SENSITIVE:
      if (patternLength == nameLength && pattern.equals(name)) {
        return new int[] { 0, patternLength };
      }
      break;
    case SearchPattern.R_PREFIX_MATCH:
      if (patternLength <= nameLength && name.substring(0, patternLength).equalsIgnoreCase(pattern)) {
        return new int[] { 0, patternLength };
      }
      break;
    case SearchPattern.R_PREFIX_MATCH | SearchPattern.R_CASE_SENSITIVE:
      if (name.startsWith(pattern)) {
        return new int[] { 0, patternLength };
      }
      break;
    case SearchPattern.R_CAMELCASE_SAME_PART_COUNT_MATCH:
      countMatch = true;
      //$FALL-THROUGH$
    case SearchPattern.R_CAMELCASE_MATCH:
      if (patternLength <= nameLength) {
        int[] regions = StringOperation.getCamelCaseMatchingRegions(pattern, 0, patternLength, name, 0, nameLength, countMatch);
        if (regions != null) return regions;
        if (name.substring(0, patternLength).equalsIgnoreCase(pattern)) {
          return new int[] { 0, patternLength };
        }
      }
      break;
    case SearchPattern.R_CAMELCASE_SAME_PART_COUNT_MATCH | SearchPattern.R_CASE_SENSITIVE:
      countMatch = true;
      //$FALL-THROUGH$
    case SearchPattern.R_CAMELCASE_MATCH | SearchPattern.R_CASE_SENSITIVE:
      if (patternLength <= nameLength) {
        return StringOperation.getCamelCaseMatchingRegions(pattern, 0, patternLength, name, 0, nameLength, countMatch);
      }
      break;
    case SearchPattern.R_PATTERN_MATCH:
      return StringOperation.getPatternMatchingRegions(pattern, 0, patternLength, name, 0, nameLength, false);
    case SearchPattern.R_PATTERN_MATCH | SearchPattern.R_CASE_SENSITIVE:
      return StringOperation.getPatternMatchingRegions(pattern, 0, patternLength, name, 0, nameLength, true);
  }
  return null;
}

/**
* Returns a search pattern that combines the given two patterns into an
* "and" pattern. The search result will match both the left pattern and
* the right pattern.
*
* @param leftPattern the left pattern
* @param rightPattern the right pattern
* @return an "and" pattern
* @deprecated Unfortunately, this functionality is not fully supported yet
*   (see "https://bugs.eclipse.org/bugs/show_bug.cgi?id=142044" for more details).
*   This might be done in a further version...
*/
public static SearchPattern createAndPattern(SearchPattern leftPattern, SearchPattern rightPattern) {
  return new AndPattern(leftPattern, rightPattern);
}

private static SearchPattern createFieldPattern(String patternString, int limitTo, int matchRule) {

  Scanner scanner = new Scanner(false /*comment*/, true /*whitespace*/, false /*nls*/, ClassFileConstants.JDK1_3/*sourceLevel*/, null /*taskTags*/, null/*taskPriorities*/, true/*taskCaseSensitive*/);
  scanner.setSource(patternString.toCharArray());
  final int InsideDeclaringPart = 1;
  final int InsideType = 2;
  int lastToken = -1;

  String declaringType = null, fieldName = null;
  String type = null;
  int mode = InsideDeclaringPart;
  int token;
  try {
    token = scanner.getNextToken();
  } catch (InvalidInputException e) {
    return null;
  }
  while (token != TerminalTokens.TokenNameEOF) {
    switch(mode) {
      // read declaring type and fieldName
      case InsideDeclaringPart :
        switch (token) {
          case TerminalTokens.TokenNameDOT:
            if (declaringType == null) {
              if (fieldName == null) return null;
              declaringType = fieldName;
            } else {
              String tokenSource = scanner.getCurrentTokenString();
              declaringType += tokenSource + fieldName;
            }
            fieldName = null;
            break;
          case TerminalTokens.TokenNameWHITESPACE:
            if (!(TerminalTokens.TokenNameWHITESPACE == lastToken || TerminalTokens.TokenNameDOT == lastToken))
              mode = InsideType;
            break;
          default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
            if (fieldName == null)
              fieldName = scanner.getCurrentTokenString();
            else
              fieldName += scanner.getCurrentTokenString();
        }
        break;
      // read type
      case InsideType:
        switch (token) {
          case TerminalTokens.TokenNameWHITESPACE:
            break;
          default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
            if (type == null)
              type = scanner.getCurrentTokenString();
            else
              type += scanner.getCurrentTokenString();
        }
        break;
    }
    lastToken = token;
    try {
      token = scanner.getNextToken();
    } catch (InvalidInputException e) {
      return null;
    }
  }
  if (fieldName == null) return null;

  char[] fieldNameChars = fieldName.toCharArray();
  if (fieldNameChars.length == 1 && fieldNameChars[0] == '*') fieldNameChars = null;

  char[] declaringTypeQualification = null, declaringTypeSimpleName = null;
  char[] typeQualification = null, typeSimpleName = null;

  // extract declaring type infos
  if (declaringType != null) {
    char[] declaringTypePart = declaringType.toCharArray();
    int lastDotPosition = CharOperation.lastIndexOf('.', declaringTypePart);
    if (lastDotPosition >= 0) {
      declaringTypeQualification = CharOperation.subarray(declaringTypePart, 0, lastDotPosition);
      if (declaringTypeQualification.length == 1 && declaringTypeQualification[0] == '*')
        declaringTypeQualification = null;
      declaringTypeSimpleName = CharOperation.subarray(declaringTypePart, lastDotPosition+1, declaringTypePart.length);
    } else {
      declaringTypeSimpleName = declaringTypePart;
    }
    if (declaringTypeSimpleName.length == 1 && declaringTypeSimpleName[0] == '*')
      declaringTypeSimpleName = null;
  }
  // extract type infos
  if (type != null) {
    char[] typePart = type.toCharArray();
    int lastDotPosition = CharOperation.lastIndexOf('.', typePart);
    if (lastDotPosition >= 0) {
      typeQualification = CharOperation.subarray(typePart, 0, lastDotPosition);
      if (typeQualification.length == 1 && typeQualification[0] == '*') {
        typeQualification = null;
      } else {
        // prefix with a '*' as the full qualification could be bigger (because of an import)
        typeQualification = CharOperation.concat(IIndexConstants.ONE_STAR, typeQualification);
      }
      typeSimpleName = CharOperation.subarray(typePart, lastDotPosition+1, typePart.length);
    } else {
      typeSimpleName = typePart;
    }
    if (typeSimpleName.length == 1 && typeSimpleName[0] == '*')
      typeSimpleName = null;
  }
  // Create field pattern
  return new FieldPattern(
      fieldNameChars,
      declaringTypeQualification,
      declaringTypeSimpleName,
      typeQualification,
      typeSimpleName,
      limitTo,
      matchRule);
}

private static SearchPattern createMethodOrConstructorPattern(String patternString, int limitTo, int matchRule, boolean isConstructor) {

  Scanner scanner = new Scanner(false /*comment*/, true /*whitespace*/, false /*nls*/, ClassFileConstants.JDK1_3/*sourceLevel*/, null /*taskTags*/, null/*taskPriorities*/, true/*taskCaseSensitive*/);
  scanner.setSource(patternString.toCharArray());
  final int InsideSelector = 1;
  final int InsideTypeArguments = 2;
  final int InsideParameter = 3;
  final int InsideReturnType = 4;
  int lastToken = -1;

  String declaringType = null, selector = null, parameterType = null;
  String[] parameterTypes = null;
  char[][] typeArguments = null;
  String typeArgumentsString = null;
  int parameterCount = -1;
  String returnType = null;
  boolean foundClosingParenthesis = false;
  int mode = InsideSelector;
  int token, argCount = 0;
  try {
    token = scanner.getNextToken();
  } catch (InvalidInputException e) {
    return null;
  }
  while (token != TerminalTokens.TokenNameEOF) {
    switch(mode) {
      // read declaring type and selector
      case InsideSelector :
        if (argCount == 0) {
          switch (token) {
            case TerminalTokens.TokenNameLESS:
              argCount++;
              if (selector == null || lastToken == TerminalTokens.TokenNameDOT) {
                typeArgumentsString = scanner.getCurrentTokenString();
                mode = InsideTypeArguments;
                break;
              }
              if (declaringType == null) {
                declaringType = selector;
              } else {
                declaringType += '.' + selector;
              }
              declaringType += scanner.getCurrentTokenString();
              selector = null;
              break;
            case TerminalTokens.TokenNameDOT:
              if (!isConstructor && typeArgumentsString != null) return null; // invalid syntax
              if (declaringType == null) {
                if (selector == null) return null; // invalid syntax
                declaringType = selector;
              } else if (selector != null) {
                declaringType += scanner.getCurrentTokenString() + selector;
              }
              selector = null;
              break;
            case TerminalTokens.TokenNameLPAREN:
              parameterTypes = new String[5];
              parameterCount = 0;
              mode = InsideParameter;
              break;
            case TerminalTokens.TokenNameWHITESPACE:
              switch (lastToken) {
                case TerminalTokens.TokenNameWHITESPACE:
                case TerminalTokens.TokenNameDOT:
                case TerminalTokens.TokenNameGREATER:
                case TerminalTokens.TokenNameRIGHT_SHIFT:
                case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
                  break;
                default:
                  mode = InsideReturnType;
                  break;
              }
              break;
            default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
              if (selector == null)
                selector = scanner.getCurrentTokenString();
              else
                selector += scanner.getCurrentTokenString();
              break;
          }
        } else {
          if (declaringType == null) return null; // invalid syntax
          switch (token) {
            case TerminalTokens.TokenNameGREATER:
            case TerminalTokens.TokenNameRIGHT_SHIFT:
            case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
              argCount--;
              break;
            case TerminalTokens.TokenNameLESS:
              argCount++;
              break;
          }
          declaringType += scanner.getCurrentTokenString();
        }
        break;
      // read type arguments
      case InsideTypeArguments:
        if (typeArgumentsString == null) return null; // invalid syntax
        typeArgumentsString += scanner.getCurrentTokenString();
        switch (token) {
          case TerminalTokens.TokenNameGREATER:
          case TerminalTokens.TokenNameRIGHT_SHIFT:
          case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
            argCount--;
            if (argCount == 0) {
              String pseudoType = "Type"+typeArgumentsString; //$NON-NLS-1$
              typeArguments = Signature.getTypeArguments(Signature.createTypeSignature(pseudoType, false).toCharArray());
              mode = InsideSelector;
            }
            break;
          case TerminalTokens.TokenNameLESS:
            argCount++;
            break;
        }
        break;
      // read parameter types
      case InsideParameter :
        if (argCount == 0) {
          switch (token) {
            case TerminalTokens.TokenNameWHITESPACE:
              break;
            case TerminalTokens.TokenNameCOMMA:
              if (parameterType == null) return null;
              if (parameterTypes != null) {
                if (parameterTypes.length == parameterCount)
                  System.arraycopy(parameterTypes, 0, parameterTypes = new String[parameterCount*2], 0, parameterCount);
                parameterTypes[parameterCount++] = parameterType;
              }
              parameterType = null;
              break;
            case TerminalTokens.TokenNameRPAREN:
              foundClosingParenthesis = true;
              if (parameterType != null && parameterTypes != null) {
                if (parameterTypes.length == parameterCount)
                  System.arraycopy(parameterTypes, 0, parameterTypes = new String[parameterCount*2], 0, parameterCount);
                parameterTypes[parameterCount++] = parameterType;
              }
              mode = isConstructor ? InsideTypeArguments : InsideReturnType;
              break;
            case TerminalTokens.TokenNameLESS:
              argCount++;
              if (parameterType == null) return null; // invalid syntax
              // $FALL-THROUGH$ - fall through next case to add token
            default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
              if (parameterType == null)
                parameterType = scanner.getCurrentTokenString();
              else
                parameterType += scanner.getCurrentTokenString();
          }
        } else {
          if (parameterType == null) return null; // invalid syntax
          switch (token) {
            case TerminalTokens.TokenNameGREATER:
            case TerminalTokens.TokenNameRIGHT_SHIFT:
            case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
              argCount--;
              break;
            case TerminalTokens.TokenNameLESS:
              argCount++;
              break;
          }
          parameterType += scanner.getCurrentTokenString();
        }
        break;
      // read return type
      case InsideReturnType:
        if (argCount == 0) {
          switch (token) {
            case TerminalTokens.TokenNameWHITESPACE:
              break;
            case TerminalTokens.TokenNameLPAREN:
              parameterTypes = new String[5];
              parameterCount = 0;
              mode = InsideParameter;
              break;
            case TerminalTokens.TokenNameLESS:
              argCount++;
              if (returnType == null) return null; // invalid syntax
              // $FALL-THROUGH$ - fall through next case to add token
            default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
              if (returnType == null)
                returnType = scanner.getCurrentTokenString();
              else
                returnType += scanner.getCurrentTokenString();
          }
        } else {
          if (returnType == null) return null; // invalid syntax
          switch (token) {
            case TerminalTokens.TokenNameGREATER:
            case TerminalTokens.TokenNameRIGHT_SHIFT:
            case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
              argCount--;
              break;
            case TerminalTokens.TokenNameLESS:
              argCount++;
              break;
          }
          returnType += scanner.getCurrentTokenString();
        }
        break;
    }
    lastToken = token;
    try {
      token = scanner.getNextToken();
    } catch (InvalidInputException e) {
      return null;
    }
  }
  // parenthesis mismatch
  if (parameterCount>0 && !foundClosingParenthesis) return null;
  // type arguments mismatch
  if (argCount > 0) return null;

  char[] selectorChars = null;
  if (isConstructor) {
    // retrieve type for constructor patterns
    if (declaringType == null)
      declaringType = selector;
    else if (selector != null)
      declaringType += '.' + selector;
  } else {
    // get selector chars
    if (selector == null) return null;
    selectorChars = selector.toCharArray();
    if (selectorChars.length == 1 && selectorChars[0] == '*')
      selectorChars = null;
  }

  char[] declaringTypeQualification = null, declaringTypeSimpleName = null;
  char[] returnTypeQualification = null, returnTypeSimpleName = null;
  char[][] parameterTypeQualifications = null, parameterTypeSimpleNames = null;
  // Signatures
  String declaringTypeSignature = null;
  String returnTypeSignature = null;
  String[] parameterTypeSignatures = null;

  // extract declaring type infos
  if (declaringType != null) {
    // get declaring type part and signature
    char[] declaringTypePart = null;
    try {
      declaringTypeSignature = Signature.createTypeSignature(declaringType, false);
      if (declaringTypeSignature.indexOf(Signature.C_GENERIC_START) < 0) {
        declaringTypePart = declaringType.toCharArray();
      } else {
        declaringTypePart = Signature.toCharArray(Signature.getTypeErasure(declaringTypeSignature.toCharArray()));
      }
    }
    catch (IllegalArgumentException iae) {
      // declaring type is invalid
      return null;
    }
    int lastDotPosition = CharOperation.lastIndexOf('.', declaringTypePart);
    if (lastDotPosition >= 0) {
      declaringTypeQualification = CharOperation.subarray(declaringTypePart, 0, lastDotPosition);
      if (declaringTypeQualification.length == 1 && declaringTypeQualification[0] == '*')
        declaringTypeQualification = null;
      declaringTypeSimpleName = CharOperation.subarray(declaringTypePart, lastDotPosition+1, declaringTypePart.length);
    } else {
      declaringTypeSimpleName = declaringTypePart;
    }
    if (declaringTypeSimpleName.length == 1 && declaringTypeSimpleName[0] == '*')
      declaringTypeSimpleName = null;
  }
  // extract parameter types infos
  if (parameterCount >= 0) {
    parameterTypeQualifications = new char[parameterCount][];
    parameterTypeSimpleNames = new char[parameterCount][];
    parameterTypeSignatures = new String[parameterCount];
    for (int i = 0; i < parameterCount; i++) {
      // get parameter type part and signature
      char[] parameterTypePart = null;
      try {
        if (parameterTypes != null) {
          parameterTypeSignatures[i] = Signature.createTypeSignature(parameterTypes[i], false);
          if (parameterTypeSignatures[i].indexOf(Signature.C_GENERIC_START) < 0) {
            parameterTypePart = parameterTypes[i].toCharArray();
          } else {
            parameterTypePart = Signature.toCharArray(Signature.getTypeErasure(parameterTypeSignatures[i].toCharArray()));
          }
        }
      }
      catch (IllegalArgumentException iae) {
        // string is not a valid type syntax
        return null;
      }
      int lastDotPosition = parameterTypePart==null ? -1 : CharOperation.lastIndexOf('.', parameterTypePart);
      if (parameterTypePart != null && lastDotPosition >= 0) {
        parameterTypeQualifications[i] = CharOperation.subarray(parameterTypePart, 0, lastDotPosition);
        if (parameterTypeQualifications[i].length == 1 && parameterTypeQualifications[i][0] == '*') {
          parameterTypeQualifications[i] = null;
        } else {
          // prefix with a '*' as the full qualification could be bigger (because of an import)
          parameterTypeQualifications[i] = CharOperation.concat(IIndexConstants.ONE_STAR, parameterTypeQualifications[i]);
        }
        parameterTypeSimpleNames[i] = CharOperation.subarray(parameterTypePart, lastDotPosition+1, parameterTypePart.length);
      } else {
        parameterTypeQualifications[i] = null;
        parameterTypeSimpleNames[i] = parameterTypePart;
      }
      if (parameterTypeSimpleNames[i].length == 1 && parameterTypeSimpleNames[i][0] == '*')
        parameterTypeSimpleNames[i] = null;
    }
  }
  // extract return type infos
  if (returnType != null) {
    // get return type part and signature
    char[] returnTypePart = null;
    try {
      returnTypeSignature = Signature.createTypeSignature(returnType, false);
      if (returnTypeSignature.indexOf(Signature.C_GENERIC_START) < 0) {
        returnTypePart = returnType.toCharArray();
      } else {
        returnTypePart = Signature.toCharArray(Signature.getTypeErasure(returnTypeSignature.toCharArray()));
      }
    }
    catch (IllegalArgumentException iae) {
      // declaring type is invalid
      return null;
    }
    int lastDotPosition = CharOperation.lastIndexOf('.', returnTypePart);
    if (lastDotPosition >= 0) {
      returnTypeQualification = CharOperation.subarray(returnTypePart, 0, lastDotPosition);
      if (returnTypeQualification.length == 1 && returnTypeQualification[0] == '*') {
        returnTypeQualification = null;
      } else {
        // because of an import
        returnTypeQualification = CharOperation.concat(IIndexConstants.ONE_STAR, returnTypeQualification);
      }
      returnTypeSimpleName = CharOperation.subarray(returnTypePart, lastDotPosition+1, returnTypePart.length);
    } else {
      returnTypeSimpleName = returnTypePart;
    }
    if (returnTypeSimpleName.length == 1 && returnTypeSimpleName[0] == '*')
      returnTypeSimpleName = null;
  }
  // Create method/constructor pattern
  if (isConstructor) {
    return new ConstructorPattern(
        declaringTypeSimpleName,
        declaringTypeQualification,
        declaringTypeSignature,
        parameterTypeQualifications,
        parameterTypeSimpleNames,
        parameterTypeSignatures,
        typeArguments,
        limitTo,
        matchRule);
  } else {
    return new MethodPattern(
        selectorChars,
        declaringTypeQualification,
        declaringTypeSimpleName,
        declaringTypeSignature,
        returnTypeQualification,
        returnTypeSimpleName,
        returnTypeSignature,
        parameterTypeQualifications,
        parameterTypeSimpleNames,
        parameterTypeSignatures,
        typeArguments,
        limitTo,
        matchRule);
  }
}

/**
* Returns a search pattern that combines the given two patterns into an
* "or" pattern. The search result will match either the left pattern or the
* right pattern.
*
* @param leftPattern the left pattern
* @param rightPattern the right pattern
* @return an "or" pattern
*/
public static SearchPattern createOrPattern(SearchPattern leftPattern, SearchPattern rightPattern) {
  return new OrPattern(leftPattern, rightPattern);
}

private static SearchPattern createPackagePattern(String patternString, int limitTo, int matchRule) {
  switch (limitTo) {
    case IJavaSearchConstants.DECLARATIONS :
      return new PackageDeclarationPattern(patternString.toCharArray(), matchRule);
    case IJavaSearchConstants.REFERENCES :
      return new PackageReferencePattern(patternString.toCharArray(), matchRule);
    case IJavaSearchConstants.ALL_OCCURRENCES :
      return new OrPattern(
        new PackageDeclarationPattern(patternString.toCharArray(), matchRule),
        new PackageReferencePattern(patternString.toCharArray(), matchRule)
      );
  }
  return null;
}

/**
* Returns a search pattern based on a given string pattern. The string patterns support '*' wild-cards.
* The remaining parameters are used to narrow down the type of expected results.
*
* <br>
*  Examples:
<ul>
*     <li>search for case insensitive references to <code>Object</code>:
*      <code>createSearchPattern("Object", IJavaSearchConstants.TYPE, IJavaSearchConstants.REFERENCES, false);</code></li>
*    <li>search for case sensitive references to exact <code>Object()</code> constructor:
*      <code>createSearchPattern("java.lang.Object()", IJavaSearchConstants.CONSTRUCTOR, IJavaSearchConstants.REFERENCES, true);</code></li>
*    <li>search for implementers of <code>java.lang.Runnable</code>:
*      <code>createSearchPattern("java.lang.Runnable", IJavaSearchConstants.TYPE, IJavaSearchConstants.IMPLEMENTORS, true);</code></li>
</ul>
* @param stringPattern the given pattern
* <ul>
*   <li>Type patterns have the following syntax:
*     <p><b><code>[qualification '.']typeName ['&lt;' typeArguments '&gt;']</code></b></p>
*      <p>Examples:</p>
*      <ul>
*       <li><code>java.lang.Object</code></li>
*        <li><code>Runnable</code></li>
*        <li><code>List&lt;String&gt;</code></li>
*      </ul>
*      <p>
*      Type arguments can be specified to search for references to parameterized types
*     using following syntax:</p><p>
*     <b><code>'&lt;' { [ '?' {'extends'|'super'} ] type ( ',' [ '?' {'extends'|'super'} ] type )* | '?' } '&gt;'</code></b>
*     </p><div style="font-style:italic;">
*     Note that:
*     <ul>
*       <li>'*' is not valid inside type arguments definition &lt;&gt;</li>
*       <li>'?' is treated as a wildcard when it is inside &lt;&gt; (i.e. it must be put on first position of the type argument)</li>
*     </ul>
*     </div>
*   </li>
*   <li>Method patterns have the following syntax:
*     <p><b><code>[declaringType '.'] ['&lt;' typeArguments '&gt;'] methodName ['(' parameterTypes ')'] [returnType]</code></b></p>
*      <p>Type arguments have the same syntax as explained in the type patterns section.</p>
*      <p>Examples:</p>
*      <ul>
*        <li><code>java.lang.Runnable.run() void</code></li>
*        <li><code>main(*)</code></li>
*        <li><code>&lt;String&gt;toArray(String[])</code></li>
*      </ul>
</li>
*   <li>Constructor patterns have the following syntax:
*      <p><b><code>['&lt;' typeArguments '&gt;'] [declaringQualification '.'] typeName ['(' parameterTypes ')']</code></b></p>
*      <p>Type arguments have the same syntax as explained in the type patterns section.</p>
*      <p><i>Note that the constructor name should not be entered as it is always the same as the type name.</i></p>
*      <p>Examples:</p>
*      <ul>
*        <li><code>java.lang.Object()</code></li>
*        <li><code>Test(*)</code></li>
*        <li><code>&lt;Exception&gt;Sample(Exception)</code></li>
*      </ul>
*     <br>
*   </li>
*   <li>Field patterns have the following syntax:
*      <p><b><code>[declaringType '.'] fieldName [fieldType]</code></b></p>
*      <p>Examples:</p>
*      <ul>
*        <li><code>java.lang.String.serialVersionUID long</code></li>
*        <li><code>field*</code></li>
*      </ul>
*   </li>
*   <li>Package patterns have the following syntax:
*      <p><b><code>packageNameSegment {'.' packageNameSegment}</code></b></p>
*      <p>Examples:</p>
*      <ul>
*        <li><code>java.lang</code></li>
*        <li><code>org.e*.jdt.c*e</code></li>
*      </ul>
*   </li>
* </ul>
* @param searchFor determines the nature of the searched elements
<ul>
*   <li>{@link IJavaSearchConstants#CLASS}: only look for classes</li>
<li>{@link IJavaSearchConstants#INTERFACE}: only look for interfaces</li>
*   <li>{@link IJavaSearchConstants#ENUM}: only look for enumeration</li>
<li>{@link IJavaSearchConstants#ANNOTATION_TYPE}: only look for annotation type</li>
*   <li>{@link IJavaSearchConstants#CLASS_AND_ENUM}: only look for classes and enumerations</li>
<li>{@link IJavaSearchConstants#CLASS_AND_INTERFACE}: only look for classes and interfaces</li>
*   <li>{@link IJavaSearchConstants#TYPE}: look for all types (i.e. classes, interfaces, enum and annotation types)</li>
<li>{@link IJavaSearchConstants#FIELD}: look for fields</li>
<li>{@link IJavaSearchConstants#METHOD}: look for methods</li>
<li>{@link IJavaSearchConstants#CONSTRUCTOR}: look for constructors</li>
<li>{@link IJavaSearchConstants#PACKAGE}: look for packages</li>
</ul>
* @param limitTo determines the nature of the expected matches
<ul>
*   <li>{@link IJavaSearchConstants#DECLARATIONS DECLARATIONS}: will search declarations matching
*       with the corresponding element. In case the element is a method, declarations of matching
*       methods in sub-types will also be found, allowing to find declarations of abstract methods, etc.<br>
*       Note that additional flags {@link IJavaSearchConstants#IGNORE_DECLARING_TYPE IGNORE_DECLARING_TYPE} and
*       {@link IJavaSearchConstants#IGNORE_RETURN_TYPE IGNORE_RETURN_TYPE} are ignored for string patterns.
*       This is due to the fact that client may omit to define them in string pattern to have same behavior.
*   </li>
*     <li>{@link IJavaSearchConstants#REFERENCES REFERENCES}: will search references to the given element.</li>
*     <li>{@link IJavaSearchConstants#ALL_OCCURRENCES ALL_OCCURRENCES}: will search for either declarations or
*        references as specified above.
*    </li>
*     <li>{@link IJavaSearchConstants#IMPLEMENTORS IMPLEMENTORS}: for types, will find all types
*        which directly implement/extend a given interface.
*        Note that types may be only classes or only interfaces if {@link IJavaSearchConstants#CLASS CLASS} or
*        {@link IJavaSearchConstants#INTERFACE INTERFACE} is respectively used instead of {@link IJavaSearchConstants#TYPE TYPE}.
*    </li>
*     <li>All other fine grain constants defined in the <b>limitTo</b> category
*        of the {@link IJavaSearchConstants} are also accepted nature:
*       <table border=0>
*           <tr>
*             <th align=left>Fine grain constant
*             <th align=left>Meaning
*           <tr>
*             <td>{@link IJavaSearchConstants#FIELD_DECLARATION_TYPE_REFERENCE FIELD_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a field declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a local variable declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#PARAMETER_DECLARATION_TYPE_REFERENCE PARAMETER_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a method parameter declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPERTYPE_TYPE_REFERENCE SUPERTYPE_TYPE_REFERENCE}
*             <td>Return only type references used as a super type or as a super interface.
*           <tr>
*             <td>{@link IJavaSearchConstants#THROWS_CLAUSE_TYPE_REFERENCE THROWS_CLAUSE_TYPE_REFERENCE}
*             <td>Return only type references used in a throws clause.
*           <tr>
*             <td>{@link IJavaSearchConstants#CAST_TYPE_REFERENCE CAST_TYPE_REFERENCE}
*             <td>Return only type references used in a cast expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#CATCH_TYPE_REFERENCE CATCH_TYPE_REFERENCE}
*             <td>Return only type references used in a catch header.
*           <tr>
*             <td>{@link IJavaSearchConstants#CLASS_INSTANCE_CREATION_TYPE_REFERENCE CLASS_INSTANCE_CREATION_TYPE_REFERENCE}
*             <td>Return only type references used in class instance creation.
*           <tr>
*             <td>{@link IJavaSearchConstants#RETURN_TYPE_REFERENCE RETURN_TYPE_REFERENCE}
*             <td>Return only type references used as a method return type.
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPORT_DECLARATION_TYPE_REFERENCE IMPORT_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used in an import declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#ANNOTATION_TYPE_REFERENCE ANNOTATION_TYPE_REFERENCE}
*             <td>Return only type references used as an annotation.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_ARGUMENT_TYPE_REFERENCE TYPE_ARGUMENT_TYPE_REFERENCE}
*             <td>Return only type references used as a type argument in a parameterized type or a parameterized method.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_VARIABLE_BOUND_TYPE_REFERENCE TYPE_VARIABLE_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a type variable bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#WILDCARD_BOUND_TYPE_REFERENCE WILDCARD_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a wildcard bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#INSTANCEOF_TYPE_REFERENCE INSTANCEOF_TYPE_REFERENCE}
*             <td>Return only type references used as a type of an <code>instanceof</code> expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPER_REFERENCE SUPER_REFERENCE}
*             <td>Return only super field accesses or super method invocations (e.g. using the <code>super</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#QUALIFIED_REFERENCE QUALIFIED_REFERENCE}
*             <td>Return only qualified field accesses or qualified method invocations.
*           <tr>
*             <td>{@link IJavaSearchConstants#THIS_REFERENCE THIS_REFERENCE}
*             <td>Return only primary field accesses or primary method invocations (e.g. using the <code>this</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPLICIT_THIS_REFERENCE IMPLICIT_THIS_REFERENCE}
*             <td>Return only field accesses or method invocations without any qualification.
*       </table>
*    </li>
</ul>
* @param matchRule one of the following match rules
*   <ul>
*     <li>{@link #R_EXACT_MATCH}</li>
*     <li>{@link #R_PREFIX_MATCH}</li>
*     <li>{@link #R_PATTERN_MATCH}</li>
*     <li>{@link #R_REGEXP_MATCH}</li>
*     <li>{@link #R_CAMELCASE_MATCH}</li>
*     <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}</li>
*   </ul>
*   , which may be also combined with one of the following flags:
*   <ul>
*     <li>{@link #R_CASE_SENSITIVE}</li>
*     <li>{@link #R_ERASURE_MATCH}</li>
*     <li>{@link #R_EQUIVALENT_MATCH}</li>
*   </ul>
*    For example,
*    <ul>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_CASE_SENSITIVE}: if an exact
*        and case sensitive match is requested,</li>
*      <li>{@link #R_PREFIX_MATCH} if a case insensitive prefix match is requested</li>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_ERASURE_MATCH}: if a case
*        insensitive and erasure match is requested.</li>
*    </ul>
*   <p>Note that {@link #R_ERASURE_MATCH} or {@link #R_EQUIVALENT_MATCH} has no effect
*   on non-generic types/methods search.</p>
*   <p>
*   Note also that the default behavior for generic types/methods search is to find exact matches.</p>
* @return a search pattern on the given string pattern, or <code>null</code> if the string pattern is ill-formed
*/
public static SearchPattern createPattern(String stringPattern, int searchFor, int limitTo, int matchRule) {
  if (stringPattern == null || stringPattern.length() == 0) return null;

  if ((matchRule = validateMatchRule(stringPattern, matchRule)) == -1) {
    return null;
  }

  // Ignore additional nature flags
  limitTo &= ~(IJavaSearchConstants.IGNORE_DECLARING_TYPE+IJavaSearchConstants.IGNORE_RETURN_TYPE);

  switch (searchFor) {
    case IJavaSearchConstants.CLASS:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.CLASS_SUFFIX);
    case IJavaSearchConstants.CLASS_AND_INTERFACE:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.CLASS_AND_INTERFACE_SUFFIX);
    case IJavaSearchConstants.CLASS_AND_ENUM:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.CLASS_AND_ENUM_SUFFIX);
    case IJavaSearchConstants.INTERFACE:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.INTERFACE_SUFFIX);
    case IJavaSearchConstants.INTERFACE_AND_ANNOTATION:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.INTERFACE_AND_ANNOTATION_SUFFIX);
    case IJavaSearchConstants.ENUM:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.ENUM_SUFFIX);
    case IJavaSearchConstants.ANNOTATION_TYPE:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.ANNOTATION_TYPE_SUFFIX);
    case IJavaSearchConstants.TYPE:
      return createTypePattern(stringPattern, limitTo, matchRule, IIndexConstants.TYPE_SUFFIX);
    case IJavaSearchConstants.METHOD:
      return createMethodOrConstructorPattern(stringPattern, limitTo, matchRule, false/*not a constructor*/);
    case IJavaSearchConstants.CONSTRUCTOR:
      return createMethodOrConstructorPattern(stringPattern, limitTo, matchRule, true/*constructor*/);
    case IJavaSearchConstants.FIELD:
      return createFieldPattern(stringPattern, limitTo, matchRule);
    case IJavaSearchConstants.PACKAGE:
      return createPackagePattern(stringPattern, limitTo, matchRule);
  }
  return null;
}

/**
* Returns a search pattern based on a given Java element.
* The pattern is used to trigger the appropriate search.
* <br>
* Note that for generic searches, the returned pattern consider {@link #R_ERASURE_MATCH} matches.
* If other kind of generic matches (i.e. {@link #R_EXACT_MATCH} or {@link #R_EQUIVALENT_MATCH})
* are expected, {@link #createPattern(IJavaElement, int, int)} method need to be used instead with
* the explicit match rule specified.
* <br>
* The pattern can be parameterized as follows:
*
* @param element the Java element the search pattern is based on
* @param limitTo determines the nature of the expected matches
<ul>
*   <li>{@link IJavaSearchConstants#DECLARATIONS DECLARATIONS}: will search declarations matching
*       with the corresponding element. In case the element is a method, declarations of matching
*       methods in sub-types will also be found, allowing to find declarations of abstract methods, etc.
*        Some additional flags may be specified while searching declaration:
*        <ul>
*          <li>{@link IJavaSearchConstants#IGNORE_DECLARING_TYPE IGNORE_DECLARING_TYPE}: declaring type will be ignored
*              during the search.<br>
*              For example using following test case:
*          <pre>
*                  class A { A method() { return null; } }
*                  class B extends A { B method() { return null; } }
*                  class C { A method() { return null; } }
*          </pre>
*              search for <code>method</code> declaration with this flag
*              will return 2 matches: in A and in C
*          </li>
*          <li>{@link IJavaSearchConstants#IGNORE_RETURN_TYPE IGNORE_RETURN_TYPE}: return type will be ignored
*              during the search.<br>
*              Using same example, search for <code>method</code> declaration with this flag
*              will return 2 matches: in A and in B.
*          </li>
*        </ul>
*        Note that these two flags may be combined and both declaring and return types can be ignored
*        during the search. Then, using same example, search for <code>method</code> declaration
*        with these 2 flags will return 3 matches: in A, in B  and in C
*   </li>
*     <li>{@link IJavaSearchConstants#REFERENCES REFERENCES}: will search references to the given element.</li>
*     <li>{@link IJavaSearchConstants#ALL_OCCURRENCES ALL_OCCURRENCES}: will search for either declarations or
*        references as specified above.
*    </li>
*     <li>All other fine grain constants defined in the <b>limitTo</b> category
*        of the {@link IJavaSearchConstants} are also accepted nature:
*       <table border=0>
*           <tr>
*             <th align=left>Fine grain constant
*             <th align=left>Meaning
*           <tr>
*             <td>{@link IJavaSearchConstants#FIELD_DECLARATION_TYPE_REFERENCE FIELD_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a field declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a local variable declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#PARAMETER_DECLARATION_TYPE_REFERENCE PARAMETER_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a method parameter declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPERTYPE_TYPE_REFERENCE SUPERTYPE_TYPE_REFERENCE}
*             <td>Return only type references used as a super type or as a super interface.
*           <tr>
*             <td>{@link IJavaSearchConstants#THROWS_CLAUSE_TYPE_REFERENCE THROWS_CLAUSE_TYPE_REFERENCE}
*             <td>Return only type references used in a throws clause.
*           <tr>
*             <td>{@link IJavaSearchConstants#CAST_TYPE_REFERENCE CAST_TYPE_REFERENCE}
*             <td>Return only type references used in a cast expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#CATCH_TYPE_REFERENCE CATCH_TYPE_REFERENCE}
*             <td>Return only type references used in a catch header.
*           <tr>
*             <td>{@link IJavaSearchConstants#CLASS_INSTANCE_CREATION_TYPE_REFERENCE CLASS_INSTANCE_CREATION_TYPE_REFERENCE}
*             <td>Return only type references used in class instance creation.
*           <tr>
*             <td>{@link IJavaSearchConstants#RETURN_TYPE_REFERENCE RETURN_TYPE_REFERENCE}
*             <td>Return only type references used as a method return type.
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPORT_DECLARATION_TYPE_REFERENCE IMPORT_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used in an import declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#ANNOTATION_TYPE_REFERENCE ANNOTATION_TYPE_REFERENCE}
*             <td>Return only type references used as an annotation.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_ARGUMENT_TYPE_REFERENCE TYPE_ARGUMENT_TYPE_REFERENCE}
*             <td>Return only type references used as a type argument in a parameterized type or a parameterized method.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_VARIABLE_BOUND_TYPE_REFERENCE TYPE_VARIABLE_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a type variable bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#WILDCARD_BOUND_TYPE_REFERENCE WILDCARD_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a wildcard bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#INSTANCEOF_TYPE_REFERENCE INSTANCEOF_TYPE_REFERENCE}
*             <td>Return only type references used as a type of an <code>instanceof</code> expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPER_REFERENCE SUPER_REFERENCE}
*             <td>Return only super field accesses or super method invocations (e.g. using the <code>super</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#QUALIFIED_REFERENCE QUALIFIED_REFERENCE}
*             <td>Return only qualified field accesses or qualified method invocations.
*           <tr>
*             <td>{@link IJavaSearchConstants#THIS_REFERENCE THIS_REFERENCE}
*             <td>Return only primary field accesses or primary method invocations (e.g. using the <code>this</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPLICIT_THIS_REFERENCE IMPLICIT_THIS_REFERENCE}
*             <td>Return only field accesses or method invocations without any qualification.
*       </table>
*    </li>
</ul>
* @return a search pattern for a Java element or <code>null</code> if the given element is ill-formed
*/
public static SearchPattern createPattern(IJavaElement element, int limitTo) {
  return createPattern(element, limitTo, R_EXACT_MATCH | R_CASE_SENSITIVE | R_ERASURE_MATCH);
}

/**
* Returns a search pattern based on a given Java element.
* The pattern is used to trigger the appropriate search, and can be parameterized as follows:
*
* @param element the Java element the search pattern is based on
* @param limitTo determines the nature of the expected matches
<ul>
*   <li>{@link IJavaSearchConstants#DECLARATIONS DECLARATIONS}: will search declarations matching
*       with the corresponding element. In case the element is a method, declarations of matching
*       methods in sub-types will also be found, allowing to find declarations of abstract methods, etc.
*        Some additional flags may be specified while searching declaration:
*        <ul>
*          <li>{@link IJavaSearchConstants#IGNORE_DECLARING_TYPE IGNORE_DECLARING_TYPE}: declaring type will be ignored
*              during the search.<br>
*              For example using following test case:
*          <pre>
*                  class A { A method() { return null; } }
*                  class B extends A { B method() { return null; } }
*                  class C { A method() { return null; } }
*          </pre>
*              search for <code>method</code> declaration with this flag
*              will return 2 matches: in A and in C
*          </li>
*          <li>{@link IJavaSearchConstants#IGNORE_RETURN_TYPE IGNORE_RETURN_TYPE}: return type will be ignored
*              during the search.<br>
*              Using same example, search for <code>method</code> declaration with this flag
*              will return 2 matches: in A and in B.
*          </li>
*        </ul>
*        Note that these two flags may be combined and both declaring and return types can be ignored
*        during the search. Then, using same example, search for <code>method</code> declaration
*        with these 2 flags will return 3 matches: in A, in B  and in C
*   </li>
*     <li>{@link IJavaSearchConstants#REFERENCES REFERENCES}: will search references to the given element.</li>
*     <li>{@link IJavaSearchConstants#ALL_OCCURRENCES ALL_OCCURRENCES}: will search for either declarations or
*        references as specified above.
*    </li>
*     <li>All other fine grain constants defined in the <b>limitTo</b> category
*        of the {@link IJavaSearchConstants} are also accepted nature:
*       <table border=0>
*           <tr>
*             <th align=left>Fine grain constant
*             <th align=left>Meaning
*           <tr>
*             <td>{@link IJavaSearchConstants#FIELD_DECLARATION_TYPE_REFERENCE FIELD_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a field declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE LOCAL_VARIABLE_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a local variable declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#PARAMETER_DECLARATION_TYPE_REFERENCE PARAMETER_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used as the type of a method parameter declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPERTYPE_TYPE_REFERENCE SUPERTYPE_TYPE_REFERENCE}
*             <td>Return only type references used as a super type or as a super interface.
*           <tr>
*             <td>{@link IJavaSearchConstants#THROWS_CLAUSE_TYPE_REFERENCE THROWS_CLAUSE_TYPE_REFERENCE}
*             <td>Return only type references used in a throws clause.
*           <tr>
*             <td>{@link IJavaSearchConstants#CAST_TYPE_REFERENCE CAST_TYPE_REFERENCE}
*             <td>Return only type references used in a cast expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#CATCH_TYPE_REFERENCE CATCH_TYPE_REFERENCE}
*             <td>Return only type references used in a catch header.
*           <tr>
*             <td>{@link IJavaSearchConstants#CLASS_INSTANCE_CREATION_TYPE_REFERENCE CLASS_INSTANCE_CREATION_TYPE_REFERENCE}
*             <td>Return only type references used in class instance creation.
*           <tr>
*             <td>{@link IJavaSearchConstants#RETURN_TYPE_REFERENCE RETURN_TYPE_REFERENCE}
*             <td>Return only type references used as a method return type.
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPORT_DECLARATION_TYPE_REFERENCE IMPORT_DECLARATION_TYPE_REFERENCE}
*             <td>Return only type references used in an import declaration.
*           <tr>
*             <td>{@link IJavaSearchConstants#ANNOTATION_TYPE_REFERENCE ANNOTATION_TYPE_REFERENCE}
*             <td>Return only type references used as an annotation.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_ARGUMENT_TYPE_REFERENCE TYPE_ARGUMENT_TYPE_REFERENCE}
*             <td>Return only type references used as a type argument in a parameterized type or a parameterized method.
*           <tr>
*             <td>{@link IJavaSearchConstants#TYPE_VARIABLE_BOUND_TYPE_REFERENCE TYPE_VARIABLE_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a type variable bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#WILDCARD_BOUND_TYPE_REFERENCE WILDCARD_BOUND_TYPE_REFERENCE}
*             <td>Return only type references used as a wildcard bound.
*           <tr>
*             <td>{@link IJavaSearchConstants#INSTANCEOF_TYPE_REFERENCE INSTANCEOF_TYPE_REFERENCE}
*             <td>Return only type references used as a type of an <code>instanceof</code> expression.
*           <tr>
*             <td>{@link IJavaSearchConstants#SUPER_REFERENCE SUPER_REFERENCE}
*             <td>Return only super field accesses or super method invocations (e.g. using the <code>super</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#QUALIFIED_REFERENCE QUALIFIED_REFERENCE}
*             <td>Return only qualified field accesses or qualified method invocations.
*           <tr>
*             <td>{@link IJavaSearchConstants#THIS_REFERENCE THIS_REFERENCE}
*             <td>Return only primary field accesses or primary method invocations (e.g. using the <code>this</code> qualifier).
*           <tr>
*             <td>{@link IJavaSearchConstants#IMPLICIT_THIS_REFERENCE IMPLICIT_THIS_REFERENCE}
*             <td>Return only field accesses or method invocations without any qualification.
*       </table>
*   </li>
</ul>
* @param matchRule one of the following match rules:
*   <ul>
*     <li>{@link #R_EXACT_MATCH}</li>
*     <li>{@link #R_PREFIX_MATCH}</li>
*     <li>{@link #R_PATTERN_MATCH}</li>
*     <li>{@link #R_REGEXP_MATCH}</li>
*     <li>{@link #R_CAMELCASE_MATCH}</li>
*     <li>{@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}</li>
*   </ul>
*   , which may be also combined with one of the following flags:
*   <ul>
*     <li>{@link #R_CASE_SENSITIVE}</li>
*     <li>{@link #R_ERASURE_MATCH}</li>
*     <li>{@link #R_EQUIVALENT_MATCH}</li>
*   </ul>
*    For example,
*    <ul>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_CASE_SENSITIVE}: if an exact
*        and case sensitive match is requested,</li>
*      <li>{@link #R_PREFIX_MATCH} if a case insensitive prefix match is requested</li>
*      <li>{@link #R_EXACT_MATCH} | {@link #R_ERASURE_MATCH}: if a case
*        insensitive and erasure match is requested.</li>
*    </ul>
*   Note that {@link #R_ERASURE_MATCH} or {@link #R_EQUIVALENT_MATCH} has no effect
*   on non-generic types/methods search.
*   <p>
*   Note also that default behavior for generic types/methods search is to find exact matches.
* @return a search pattern for a Java element or <code>null</code> if the given element is ill-formed
* @since 3.1
*/
public static SearchPattern createPattern(IJavaElement element, int limitTo, int matchRule) {
  SearchPattern searchPattern = null;
  int lastDot;
  boolean ignoreDeclaringType = false;
  boolean ignoreReturnType = false;
  int maskedLimitTo = limitTo & ~(IJavaSearchConstants.IGNORE_DECLARING_TYPE+IJavaSearchConstants.IGNORE_RETURN_TYPE);
  if (maskedLimitTo == IJavaSearchConstants.DECLARATIONS || maskedLimitTo == IJavaSearchConstants.ALL_OCCURRENCES) {
    ignoreDeclaringType = (limitTo & IJavaSearchConstants.IGNORE_DECLARING_TYPE) != 0;
    ignoreReturnType = (limitTo & IJavaSearchConstants.IGNORE_RETURN_TYPE) != 0;
  }
  if ((matchRule = validateMatchRule(null, matchRule)) == -1) {
    return null;
  }
  char[] declaringSimpleName = null;
  char[] declaringQualification = null;
  switch (element.getElementType()) {
    case IJavaElement.FIELD :
      IField field = (IField) element;
      if (!ignoreDeclaringType) {
        IType declaringClass = field.getDeclaringType();
        declaringSimpleName = declaringClass.getElementName().toCharArray();
        declaringQualification = declaringClass.getPackageFragment().getElementName().toCharArray();
        char[][] enclosingNames = enclosingTypeNames(declaringClass);
        if (enclosingNames.length > 0) {
          declaringQualification = CharOperation.concat(declaringQualification, CharOperation.concatWith(enclosingNames, '.'), '.');
        }
      }
      char[] name = field.getElementName().toCharArray();
      char[] typeSimpleName = null;
      char[] typeQualification = null;
      String typeSignature = null;
      if (!ignoreReturnType) {
        try {
          typeSignature = field.getTypeSignature();
          char[] signature = typeSignature.toCharArray();
          char[] typeErasure = Signature.toCharArray(Signature.getTypeErasure(signature));
          CharOperation.replace(typeErasure, '$', '.');
          if ((lastDot = CharOperation.lastIndexOf('.', typeErasure)) == -1) {
            typeSimpleName = typeErasure;
          } else {
            typeSimpleName = CharOperation.subarray(typeErasure, lastDot + 1, typeErasure.length);
            typeQualification = CharOperation.subarray(typeErasure, 0, lastDot);
            if (!field.isBinary()) {
              // prefix with a '*' as the full qualification could be bigger (because of an import)
              typeQualification = CharOperation.concat(IIndexConstants.ONE_STAR, typeQualification);
            }
          }
        } catch (JavaModelException e) {
          return null;
        }
      }
      // Create field pattern
      searchPattern =
        new FieldPattern(
          name,
          declaringQualification,
          declaringSimpleName,
          typeQualification,
          typeSimpleName,
          typeSignature,
          limitTo,
          matchRule);
      break;
    case IJavaElement.IMPORT_DECLARATION :
      String elementName = element.getElementName();
      lastDot = elementName.lastIndexOf('.');
      if (lastDot == -1) return null; // invalid import declaration
      IImportDeclaration importDecl = (IImportDeclaration)element;
      if (importDecl.isOnDemand()) {
        searchPattern = createPackagePattern(elementName.substring(0, lastDot), maskedLimitTo, matchRule);
      } else {
        searchPattern =
          createTypePattern(
            elementName.substring(lastDot+1).toCharArray(),
            elementName.substring(0, lastDot).toCharArray(),
            null,
            null,
            null,
            maskedLimitTo,
            matchRule);
      }
      break;
    case IJavaElement.LOCAL_VARIABLE :
      LocalVariable localVar = (LocalVariable) element;
      searchPattern = new LocalVariablePattern(localVar, limitTo, matchRule);
      break;
    case IJavaElement.TYPE_PARAMETER:
      ITypeParameter typeParam = (ITypeParameter) element;
      boolean findParamDeclarations = true;
      boolean findParamReferences = true;
      switch (maskedLimitTo) {
        case IJavaSearchConstants.DECLARATIONS :
          findParamReferences = false;
          break;
        case IJavaSearchConstants.REFERENCES :
          findParamDeclarations = false;
          break;
      }
      searchPattern =
        new TypeParameterPattern(
          findParamDeclarations,
          findParamReferences,
          typeParam,
          matchRule);
      break;
    case IJavaElement.METHOD :
      IMethod method = (IMethod) element;
      boolean isConstructor;
      try {
        isConstructor = method.isConstructor();
      } catch (JavaModelException e) {
        return null;
      }
      IType declaringClass = method.getDeclaringType();
      if (ignoreDeclaringType) {
        if (isConstructor) declaringSimpleName = declaringClass.getElementName().toCharArray();
      } else {
        declaringSimpleName = declaringClass.getElementName().toCharArray();
        declaringQualification = declaringClass.getPackageFragment().getElementName().toCharArray();
        char[][] enclosingNames = enclosingTypeNames(declaringClass);
        if (enclosingNames.length > 0) {
          declaringQualification = CharOperation.concat(declaringQualification, CharOperation.concatWith(enclosingNames, '.'), '.');
        }
      }
      char[] selector = method.getElementName().toCharArray();
      char[] returnSimpleName = null;
      char[] returnQualification = null;
      String returnSignature = null;
      if (!ignoreReturnType) {
        try {
          returnSignature = method.getReturnType();
          char[] signature = returnSignature.toCharArray();
          char[] returnErasure = Signature.toCharArray(Signature.getTypeErasure(signature));
          CharOperation.replace(returnErasure, '$', '.');
          if ((lastDot = CharOperation.lastIndexOf('.', returnErasure)) == -1) {
            returnSimpleName = returnErasure;
          } else {
            returnSimpleName = CharOperation.subarray(returnErasure, lastDot + 1, returnErasure.length);
            returnQualification = CharOperation.subarray(returnErasure, 0, lastDot);
            if (!method.isBinary()) {
              // prefix with a '*' as the full qualification could be bigger (because of an import)
              CharOperation.concat(IIndexConstants.ONE_STAR, returnQualification);
            }
          }
        } catch (JavaModelException e) {
          return null;
        }
      }
      String[] parameterTypes = method.getParameterTypes();
      int paramCount = parameterTypes.length;
      char[][] parameterSimpleNames = new char[paramCount][];
      char[][] parameterQualifications = new char[paramCount][];
      String[] parameterSignatures = new String[paramCount];
      for (int i = 0; i < paramCount; i++) {
        parameterSignatures[i] = parameterTypes[i];
        char[] signature = parameterSignatures[i].toCharArray();
        char[] paramErasure = Signature.toCharArray(Signature.getTypeErasure(signature));
        CharOperation.replace(paramErasure, '$', '.');
        if ((lastDot = CharOperation.lastIndexOf('.', paramErasure)) == -1) {
          parameterSimpleNames[i] = paramErasure;
          parameterQualifications[i] = null;
        } else {
          parameterSimpleNames[i] = CharOperation.subarray(paramErasure, lastDot + 1, paramErasure.length);
          parameterQualifications[i] = CharOperation.subarray(paramErasure, 0, lastDot);
          if (!method.isBinary()) {
            // prefix with a '*' as the full qualification could be bigger (because of an import)
            CharOperation.concat(IIndexConstants.ONE_STAR, parameterQualifications[i]);
          }
        }
      }

      // Create method/constructor pattern
      if (isConstructor) {
        searchPattern =
          new ConstructorPattern(
            declaringSimpleName,
            declaringQualification,
            parameterQualifications,
            parameterSimpleNames,
            parameterSignatures,
            method,
            limitTo,
            matchRule);
      } else {
        searchPattern =
          new MethodPattern(
            selector,
            declaringQualification,
            declaringSimpleName,
            returnQualification,
            returnSimpleName,
            returnSignature,
            parameterQualifications,
            parameterSimpleNames,
            parameterSignatures,
            method,
            limitTo,
            matchRule);
      }
      break;
    case IJavaElement.TYPE :
      IType type = (IType)element;
      searchPattern =   createTypePattern(
            type.getElementName().toCharArray(),
            type.getPackageFragment().getElementName().toCharArray(),
            ignoreDeclaringType ? null : enclosingTypeNames(type),
            null,
            type,
            maskedLimitTo,
            matchRule);
      break;
    case IJavaElement.PACKAGE_DECLARATION :
    case IJavaElement.PACKAGE_FRAGMENT :
      searchPattern = createPackagePattern(element.getElementName(), maskedLimitTo, matchRule);
      break;
  }
  if (searchPattern != null)
    MatchLocator.setFocus(searchPattern, element);
  return searchPattern;
}

private static SearchPattern createTypePattern(char[] simpleName, char[] packageName, char[][] enclosingTypeNames, String typeSignature, IType type, int limitTo, int matchRule) {
  switch (limitTo) {
    case IJavaSearchConstants.DECLARATIONS :
      return new TypeDeclarationPattern(
        packageName,
        enclosingTypeNames,
        simpleName,
        IIndexConstants.TYPE_SUFFIX,
        matchRule);
    case IJavaSearchConstants.REFERENCES :
      if (type != null) {
        return new TypeReferencePattern(
          CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
          simpleName,
          type,
          matchRule);
      }
      return new TypeReferencePattern(
        CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
        simpleName,
        typeSignature,
        matchRule);
    case IJavaSearchConstants.IMPLEMENTORS :
      return new SuperTypeReferencePattern(
        CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
        simpleName,
        SuperTypeReferencePattern.ONLY_SUPER_INTERFACES,
        matchRule);
    case IJavaSearchConstants.ALL_OCCURRENCES :
      return new OrPattern(
        new TypeDeclarationPattern(
          packageName,
          enclosingTypeNames,
          simpleName,
          IIndexConstants.TYPE_SUFFIX,
          matchRule),
        (type != null)
          ? new TypeReferencePattern(
            CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
            simpleName,
            type,
            matchRule)
          : new TypeReferencePattern(
            CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
            simpleName,
            typeSignature,
            matchRule)
      );
    default:
      if (type != null) {
        return new TypeReferencePattern(
          CharOperation.concatWith(packageName, enclosingTypeNames, '.'),
          simpleName,
          type,
          limitTo,
          matchRule);
      }
  }
  return null;
}

private static SearchPattern createTypePattern(String patternString, int limitTo, int matchRule, char indexSuffix) {

  Scanner scanner = new Scanner(false /*comment*/, true /*whitespace*/, false /*nls*/, ClassFileConstants.JDK1_3/*sourceLevel*/, null /*taskTags*/, null/*taskPriorities*/, true/*taskCaseSensitive*/);
  scanner.setSource(patternString.toCharArray());
  String type = null;
  int token;
  try {
    token = scanner.getNextToken();
  } catch (InvalidInputException e) {
    return null;
  }
  int argCount = 0;
  while (token != TerminalTokens.TokenNameEOF) {
    if (argCount == 0) {
      switch (token) {
        case TerminalTokens.TokenNameWHITESPACE:
          break;
        case TerminalTokens.TokenNameLESS:
          argCount++;
          // $FALL-THROUGH$ - fall through default case to add token to type
        default: // all other tokens are considered identifiers (see bug 21763 Problem in Java search [search])
          if (type == null)
            type = scanner.getCurrentTokenString();
          else
            type += scanner.getCurrentTokenString();
      }
    } else {
      switch (token) {
        case TerminalTokens.TokenNameGREATER:
        case TerminalTokens.TokenNameRIGHT_SHIFT:
        case TerminalTokens.TokenNameUNSIGNED_RIGHT_SHIFT:
          argCount--;
          break;
        case TerminalTokens.TokenNameLESS:
          argCount++;
          break;
      }
      if (type == null) return null; // invalid syntax
      type += scanner.getCurrentTokenString();
    }
    try {
      token = scanner.getNextToken();
    } catch (InvalidInputException e) {
      return null;
    }
  }
  if (type == null) return null;
  String typeSignature = null;
  char[] qualificationChars = null, typeChars = null;

  // get type part and signature
  char[] typePart = null;
  try {
    typeSignature = Signature.createTypeSignature(type, false);
    if (typeSignature.indexOf(Signature.C_GENERIC_START) < 0) {
      typePart = type.toCharArray();
    } else {
      typePart = Signature.toCharArray(Signature.getTypeErasure(typeSignature.toCharArray()));
    }
  }
  catch (IllegalArgumentException iae) {
    // string is not a valid type syntax
    return null;
  }

  // get qualification name
  int lastDotPosition = CharOperation.lastIndexOf('.', typePart);
  if (lastDotPosition >= 0) {
    qualificationChars = CharOperation.subarray(typePart, 0, lastDotPosition);
    if (qualificationChars.length == 1 && qualificationChars[0] == '*')
      qualificationChars = null;
    typeChars = CharOperation.subarray(typePart, lastDotPosition+1, typePart.length);
  } else {
    typeChars = typePart;
  }
  if (typeChars.length == 1 && typeChars[0] == '*') {
    typeChars = null;
  }
  switch (limitTo) {
    case IJavaSearchConstants.DECLARATIONS : // cannot search for explicit member types
      return new QualifiedTypeDeclarationPattern(qualificationChars, typeChars, indexSuffix, matchRule);
    case IJavaSearchConstants.REFERENCES :
      return new TypeReferencePattern(qualificationChars, typeChars, typeSignature, indexSuffix, matchRule);
    case IJavaSearchConstants.IMPLEMENTORS :
      return new SuperTypeReferencePattern(qualificationChars, typeChars, SuperTypeReferencePattern.ONLY_SUPER_INTERFACES, indexSuffix, matchRule);
    case IJavaSearchConstants.ALL_OCCURRENCES :
      return new OrPattern(
        new QualifiedTypeDeclarationPattern(qualificationChars, typeChars, indexSuffix, matchRule),// cannot search for explicit member types
        new TypeReferencePattern(qualificationChars, typeChars, typeSignature, indexSuffix, matchRule));
    default:
      return new TypeReferencePattern(qualificationChars, typeChars, typeSignature, limitTo, indexSuffix, matchRule);
  }
}
/**
* Returns the enclosing type names of the given type.
*/
private static char[][] enclosingTypeNames(IType type) {
  IJavaElement parent = type.getParent();
  switch (parent.getElementType()) {
    case IJavaElement.CLASS_FILE:
      // For a binary type, the parent is not the enclosing type, but the declaring type is.
      // (see bug 20532  Declaration of member binary type not found)
      IType declaringType = type.getDeclaringType();
      if (declaringType == null) return CharOperation.NO_CHAR_CHAR;
      return CharOperation.arrayConcat(
        enclosingTypeNames(declaringType),
        declaringType.getElementName().toCharArray());
    case IJavaElement.COMPILATION_UNIT:
      return CharOperation.NO_CHAR_CHAR;
    case IJavaElement.FIELD:
    case IJavaElement.INITIALIZER:
    case IJavaElement.METHOD:
      IType declaringClass = ((IMember) parent).getDeclaringType();
      return CharOperation.arrayConcat(
        enclosingTypeNames(declaringClass),
        new char[][] {declaringClass.getElementName().toCharArray(), IIndexConstants.ONE_STAR});
    case IJavaElement.TYPE:
      return CharOperation.arrayConcat(
        enclosingTypeNames((IType)parent),
        parent.getElementName().toCharArray());
    default:
      return null;
  }
}

/**
* Decode the given index key in this pattern. The decoded index key is used by
* {@link #matchesDecodedKey(SearchPattern)} to find out if the corresponding index entry
* should be considered.
* <p>
* This method should be re-implemented in subclasses that need to decode an index key.
* </p>
*
* @param key the given index key
*/
public void decodeIndexKey(char[] key) {
  // called from findIndexMatches(), override as necessary
}
/**
* Query a given index for matching entries. Assumes the sender has opened the index and will close when finished.
*
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public void findIndexMatches(Index index, IndexQueryRequestor requestor, SearchParticipant participant, IJavaSearchScope scope, IProgressMonitor monitor) throws IOException {
  if (monitor != null && monitor.isCanceled()) throw new OperationCanceledException();
  try {
    index.startQuery();
    SearchPattern pattern = currentPattern();
    EntryResult[] entries = pattern.queryIn(index);
    if (entries == null) return;

    SearchPattern decodedResult = pattern.getBlankPattern();
    String containerPath = index.containerPath;
    char separator = index.separator;
    for (int i = 0, l = entries.length; i < l; i++) {
      if (monitor != null && monitor.isCanceled()) throw new OperationCanceledException();

      EntryResult entry = entries[i];
      decodedResult.decodeIndexKey(entry.getWord());
      if (pattern.matchesDecodedKey(decodedResult)) {
        // TODO (kent) some clients may not need the document names
        String[] names = entry.getDocumentNames(index);
        for (int j = 0, n = names.length; j < n; j++)
          acceptMatch(names[j], containerPath, separator, decodedResult, requestor, participant, scope, monitor);
      }
    }
  } finally {
    index.stopQuery();
  }
}
/**
* Returns a blank pattern that can be used as a record to decode an index key.
* <p>
* Implementors of this method should return a new search pattern that is going to be used
* to decode index keys.
* </p>
*
* @return a new blank pattern
* @see #decodeIndexKey(char[])
*/
public abstract SearchPattern getBlankPattern();
/**
* Returns a key to find in relevant index categories, if null then all index entries are matched.
* The key will be matched according to some match rule. These potential matches
* will be further narrowed by the match locator, but precise match locating can be expensive,
* and index query should be as accurate as possible so as to eliminate obvious false hits.
* <p>
* This method should be re-implemented in subclasses that need to narrow down the
* index query.
* </p>
*
* @return an index key from this pattern, or <code>null</code> if all index entries are matched.
*/
public char[] getIndexKey() {
  return null; // called from queryIn(), override as necessary
}
/**
* Returns an array of index categories to consider for this index query.
* These potential matches will be further narrowed by the match locator, but precise
* match locating can be expensive, and index query should be as accurate as possible
* so as to eliminate obvious false hits.
* <p>
* This method should be re-implemented in subclasses that need to narrow down the
* index query.
* </p>
*
* @return an array of index categories
*/
public char[][] getIndexCategories() {
  return CharOperation.NO_CHAR_CHAR; // called from queryIn(), override as necessary
}
/**
* Returns the rule to apply for matching index keys. Can be exact match, prefix match, pattern match or regexp match.
* Rule can also be combined with a case sensitivity flag.
*
* @return one of R_EXACT_MATCH, R_PREFIX_MATCH, R_PATTERN_MATCH, R_REGEXP_MATCH combined with R_CASE_SENSITIVE,
*   e.g. R_EXACT_MATCH | R_CASE_SENSITIVE if an exact and case sensitive match is requested,
*   or R_PREFIX_MATCH if a prefix non case sensitive match is requested.
*/
public final int getMatchRule() {
  return this.matchRule;
}
/**
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public boolean isPolymorphicSearch() {
  return false;
}
/**
* Returns whether this pattern matches the given pattern (representing a decoded index key).
* <p>
* This method should be re-implemented in subclasses that need to narrow down the
* index query.
* </p>
*
* @param decodedPattern a pattern representing a decoded index key
* @return whether this pattern matches the given pattern
*/
public boolean matchesDecodedKey(SearchPattern decodedPattern) {
  return true; // called from findIndexMatches(), override as necessary if index key is encoded
}

/**
* Returns whether the given name matches the given pattern.
* <p>
* This method should be re-implemented in subclasses that need to define how
* a name matches a pattern.
* </p>
*
* @param pattern the given pattern, or <code>null</code> to represent "*"
* @param name the given name
* @return whether the given name matches the given pattern
*/
public boolean matchesName(char[] pattern, char[] name) {
  if (pattern == null) return true; // null is as if it was "*"
  if (name != null) {
    boolean isCaseSensitive = (this.matchRule & R_CASE_SENSITIVE) != 0;
    int matchMode = this.matchRule & MODE_MASK;
    boolean emptyPattern = pattern.length == 0;
    if (emptyPattern && (this.matchRule & R_PREFIX_MATCH) != 0) return true;
    boolean sameLength = pattern.length == name.length;
    boolean canBePrefix = name.length >= pattern.length;
    boolean matchFirstChar = !isCaseSensitive || emptyPattern || (name.length > 0 &&  pattern[0] == name[0]);
    switch (matchMode) {
      case R_EXACT_MATCH :
        if (sameLength && matchFirstChar) {
          return CharOperation.equals(pattern, name, isCaseSensitive);
        }
        break;

      case R_PREFIX_MATCH :
        if (canBePrefix && matchFirstChar) {
          return CharOperation.prefixEquals(pattern, name, isCaseSensitive);
        }
        break;

      case R_PATTERN_MATCH :
        if (!isCaseSensitive)
          pattern = CharOperation.toLowerCase(pattern);
        return CharOperation.match(pattern, name, isCaseSensitive);

      case SearchPattern.R_CAMELCASE_MATCH:
        if (matchFirstChar && CharOperation.camelCaseMatch(pattern, name, false)) {
          return true;
        }
        // only test case insensitive as CamelCase already verified prefix case sensitive
        if (!isCaseSensitive && matchFirstChar && CharOperation.prefixEquals(pattern, name, false)) {
          return true;
        }
        break;

      case SearchPattern.R_CAMELCASE_SAME_PART_COUNT_MATCH:
        return matchFirstChar && CharOperation.camelCaseMatch(pattern, name, true);

      case R_REGEXP_MATCH :
        // TODO implement regular expression match
        return true;
    }
  }
  return false;
}

/**
* Validate compatibility between given string pattern and match rule.
*<br>
* In certain circumstances described in the table below, the returned match rule is
* modified in order to provide a more efficient search pattern:
* <ol>
*   <li>when the {@link #R_REGEXP_MATCH} flag is set, then <b>the pattern is
*     rejected</b> as this kind of match is not supported yet and <code>-1</code>
*     is returned).
*   </li>
*   <li>when the string pattern has <u>no</u> pattern characters (e.g. '*' or '?')
*     and the pattern match flag is set (i.e. the match rule has the {@link #R_PATTERN_MATCH}
*     flag), then <b>the pattern match flag is reset</b>.<br>
*     Reversely, when the string pattern has pattern characters and the pattern
*     match flag is <u>not</u> set, then <b>the pattern match flag is set</b>.
*   </li>
*   <li>when the {@link #R_PATTERN_MATCH} flag is set then, <b>other
*     {@link #R_PREFIX_MATCH}, {@link #R_CAMELCASE_MATCH} or
*     {@link #R_CAMELCASE_SAME_PART_COUNT_MATCH} flags are reset</b>
*     if they are tentatively combined.
*   </li>
*   <li>when the {@link #R_CAMELCASE_MATCH} flag is set, then <b>other
*     {@link #R_PREFIX_MATCH} or {@link #R_CAMELCASE_SAME_PART_COUNT_MATCH}
*     flags are reset</b> if they are tentatively combined.<br>
*     Reversely, if the string pattern cannot be a camel case pattern (i.e. contains
*     invalid Java identifier characters or does not have at least two uppercase
*     characters - one for method camel case patterns), then <b>the CamelCase
*     match flag is replaced with a prefix match flag</b>.
*   </li>
*   <li>when the {@link #R_CAMELCASE_SAME_PART_COUNT_MATCH} flag is set,
*     then <b>({@link #R_PREFIX_MATCH} flag is reset</b> if it's tentatively
*     combined.<br>
*     Reversely, if the string pattern cannot be a camel case pattern (i.e. contains
*     invalid Java identifier characters or does not have at least two uppercase
*     characters - one for method camel case patterns), then <b>the CamelCase
*     part count match flag is reset</b>.
*   </li>
* </ol>
* <i>Note: the rules are validated in the documented order. For example, it means
*   that as soon as the string pattern contains one pattern character, the pattern
*   match flag will be set and all other match flags reset: validation of rule 2)
*   followed by rule 3)...</i>
*<p>
*
* @param stringPattern The string pattern
* @param matchRule The match rule
* @return Optimized valid match rule or -1 if an incompatibility was detected.
* @since 3.2
*/
public static int validateMatchRule(String stringPattern, int matchRule) {

  // Verify Regexp match rule
  if ((matchRule & R_REGEXP_MATCH) != 0) {
    if ((matchRule & R_PATTERN_MATCH) != 0 || (matchRule & R_PREFIX_MATCH) != 0 ||
      (matchRule & R_CAMELCASE_MATCH) != 0 || (matchRule & R_CAMELCASE_SAME_PART_COUNT_MATCH) != 0) {
      // regexp is not supported yet
      return -1;
    }
  }

  // Verify Pattern match rule
  if (stringPattern != null) {
    int starIndex = stringPattern.indexOf('*');
    int questionIndex = stringPattern.indexOf('?');
    if (starIndex < 0 && questionIndex < 0) {
      // reset pattern match flag if any
      matchRule &= ~R_PATTERN_MATCH;
    } else {
      // force Pattern rule
      matchRule |= R_PATTERN_MATCH;
    }
  }
  if ((matchRule & R_PATTERN_MATCH) != 0) {
    // reset other incompatible flags
    matchRule &= ~R_CAMELCASE_MATCH;
    matchRule &= ~R_CAMELCASE_SAME_PART_COUNT_MATCH;
    matchRule &= ~R_PREFIX_MATCH;
    return matchRule;
  }

  // Verify Camel Case
  if ((matchRule & R_CAMELCASE_MATCH) != 0) {
    // reset other incompatible flags
    matchRule &= ~R_CAMELCASE_SAME_PART_COUNT_MATCH;
    matchRule &= ~R_PREFIX_MATCH;
    // validate camel case rule and modify it if not valid
    boolean validCamelCase = validateCamelCasePattern(stringPattern);
    if (!validCamelCase) {
      matchRule &= ~R_CAMELCASE_MATCH;
      matchRule |= R_PREFIX_MATCH;
    }
    return matchRule;
  }

  // Verify Camel Case with same count of parts
  if ((matchRule & R_CAMELCASE_SAME_PART_COUNT_MATCH) != 0) {
    // reset other incompatible flags
    matchRule &= ~R_PREFIX_MATCH;
    // validate camel case rule and modify it if not valid
    boolean validCamelCase = validateCamelCasePattern(stringPattern);
    if (!validCamelCase) {
      matchRule &= ~R_CAMELCASE_SAME_PART_COUNT_MATCH;
    }
    return matchRule;
  }

  // Return the validated match rule (modified if necessary)
  return matchRule;
}

/*
* Validate pattern for a camel case match rule
* @return
*/
private static boolean validateCamelCasePattern(String stringPattern) {
  if (stringPattern == null) return true;
  // verify sting pattern validity
  int length = stringPattern.length();
  boolean validCamelCase = true;
  boolean lowerCamelCase = false;
  int uppercase = 0;
  for (int i=0; i<length && validCamelCase; i++) {
    char ch = stringPattern.charAt(i);
    validCamelCase = i==0 ? ScannerHelper.isJavaIdentifierStart(ch) : ScannerHelper.isJavaIdentifierPart(ch);
    // at least one uppercase character is need in CamelCase pattern
    // (see bug https://bugs.eclipse.org/bugs/show_bug.cgi?id=136313)
    if (ScannerHelper.isUpperCase(ch)) uppercase++;
    if (i==0) lowerCamelCase = uppercase == 0;
  }
  if (validCamelCase) {
    validCamelCase = lowerCamelCase ? uppercase > 0 : uppercase > 1 ;
  }
  return validCamelCase;
}

/**
* @noreference This method is not intended to be referenced by clients.
* @nooverride This method is not intended to be re-implemented or extended by clients.
*/
public EntryResult[] queryIn(Index index) throws IOException {
  return index.query(getIndexCategories(), getIndexKey(), getMatchRule());
}

/**
* @see java.lang.Object#toString()
*/
public String toString() {
  return "SearchPattern"; //$NON-NLS-1$
}
}
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