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* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
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package org.apache.cayenne.exp;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.exp.parser.ASTAdd;
import org.apache.cayenne.exp.parser.ASTAnd;
import org.apache.cayenne.exp.parser.ASTBetween;
import org.apache.cayenne.exp.parser.ASTDbPath;
import org.apache.cayenne.exp.parser.ASTDivide;
import org.apache.cayenne.exp.parser.ASTEqual;
import org.apache.cayenne.exp.parser.ASTFalse;
import org.apache.cayenne.exp.parser.ASTGreater;
import org.apache.cayenne.exp.parser.ASTGreaterOrEqual;
import org.apache.cayenne.exp.parser.ASTIn;
import org.apache.cayenne.exp.parser.ASTLess;
import org.apache.cayenne.exp.parser.ASTLessOrEqual;
import org.apache.cayenne.exp.parser.ASTLike;
import org.apache.cayenne.exp.parser.ASTLikeIgnoreCase;
import org.apache.cayenne.exp.parser.ASTList;
import org.apache.cayenne.exp.parser.ASTMultiply;
import org.apache.cayenne.exp.parser.ASTNegate;
import org.apache.cayenne.exp.parser.ASTNot;
import org.apache.cayenne.exp.parser.ASTNotBetween;
import org.apache.cayenne.exp.parser.ASTNotEqual;
import org.apache.cayenne.exp.parser.ASTNotIn;
import org.apache.cayenne.exp.parser.ASTNotLike;
import org.apache.cayenne.exp.parser.ASTNotLikeIgnoreCase;
import org.apache.cayenne.exp.parser.ASTObjPath;
import org.apache.cayenne.exp.parser.ASTOr;
import org.apache.cayenne.exp.parser.ASTPath;
import org.apache.cayenne.exp.parser.ASTSubtract;
import org.apache.cayenne.exp.parser.ASTTrue;
import org.apache.cayenne.exp.parser.SimpleNode;
import org.apache.cayenne.map.Entity;
/**
* Helper class to build expressions. Alternatively expressions can be built using
* {@link org.apache.cayenne.exp.Expression#fromString(String)} method.
*
*/
public class ExpressionFactory {
/**
* A "split" character, "|", that is understood by some of the ExpressionFactory
* methods that require splitting joins in the middle of the path.
*
* @since 3.0
*/
public static final char SPLIT_SEPARATOR = '|';
private static Class<?>[] typeLookup;
private static volatile int autoAliasId;
static {
// make sure all types are small integers, then we can use
// them as indexes in lookup array
int[] allTypes = new int[] {
Expression.AND, Expression.OR, Expression.NOT, Expression.EQUAL_TO,
Expression.NOT_EQUAL_TO, Expression.LESS_THAN, Expression.GREATER_THAN,
Expression.LESS_THAN_EQUAL_TO, Expression.GREATER_THAN_EQUAL_TO,
Expression.BETWEEN, Expression.IN, Expression.LIKE,
Expression.LIKE_IGNORE_CASE, Expression.ADD, Expression.SUBTRACT,
Expression.MULTIPLY, Expression.DIVIDE, Expression.NEGATIVE,
Expression.OBJ_PATH, Expression.DB_PATH, Expression.LIST,
Expression.NOT_BETWEEN, Expression.NOT_IN, Expression.NOT_LIKE,
Expression.NOT_LIKE_IGNORE_CASE, Expression.TRUE, Expression.FALSE
};
int max = 0;
int min = 0;
int allLen = allTypes.length;
for (int i = 0; i < allLen; i++) {
if (allTypes[i] > max)
max = allTypes[i];
else if (allTypes[i] < min)
min = allTypes[i];
}
// sanity check....
if (max > 500)
throw new RuntimeException("Types values are too big: " + max);
if (min < 0)
throw new RuntimeException("Types values are too small: " + min);
// now we know that if types are used as indexes,
// they will fit in array "max + 1" long (though gaps are possible)
typeLookup = new Class[max + 1];
typeLookup[Expression.AND] = ASTAnd.class;
typeLookup[Expression.OR] = ASTOr.class;
typeLookup[Expression.BETWEEN] = ASTBetween.class;
typeLookup[Expression.NOT_BETWEEN] = ASTNotBetween.class;
// binary types
typeLookup[Expression.EQUAL_TO] = ASTEqual.class;
typeLookup[Expression.NOT_EQUAL_TO] = ASTNotEqual.class;
typeLookup[Expression.LESS_THAN] = ASTLess.class;
typeLookup[Expression.GREATER_THAN] = ASTGreater.class;
typeLookup[Expression.LESS_THAN_EQUAL_TO] = ASTLessOrEqual.class;
typeLookup[Expression.GREATER_THAN_EQUAL_TO] = ASTGreaterOrEqual.class;
typeLookup[Expression.IN] = ASTIn.class;
typeLookup[Expression.NOT_IN] = ASTNotIn.class;
typeLookup[Expression.LIKE] = ASTLike.class;
typeLookup[Expression.LIKE_IGNORE_CASE] = ASTLikeIgnoreCase.class;
typeLookup[Expression.NOT_LIKE] = ASTNotLike.class;
typeLookup[Expression.NOT_LIKE_IGNORE_CASE] = ASTNotLikeIgnoreCase.class;
typeLookup[Expression.ADD] = ASTAdd.class;
typeLookup[Expression.SUBTRACT] = ASTSubtract.class;
typeLookup[Expression.MULTIPLY] = ASTMultiply.class;
typeLookup[Expression.DIVIDE] = ASTDivide.class;
typeLookup[Expression.NOT] = ASTNot.class;
typeLookup[Expression.NEGATIVE] = ASTNegate.class;
typeLookup[Expression.OBJ_PATH] = ASTObjPath.class;
typeLookup[Expression.DB_PATH] = ASTDbPath.class;
typeLookup[Expression.LIST] = ASTList.class;
typeLookup[Expression.TRUE] = ASTTrue.class;
typeLookup[Expression.FALSE] = ASTFalse.class;
}
/**
* Creates a new expression for the type requested. If type is unknown,
* ExpressionException is thrown.
*/
public static Expression expressionOfType(int type) {
if (type < 0 || type >= typeLookup.length) {
throw new ExpressionException("Bad expression type: " + type);
}
if (typeLookup[type] == null) {
throw new ExpressionException("Bad expression type: " + type);
}
// expected this
if (SimpleNode.class.isAssignableFrom(typeLookup[type])) {
try {
return (Expression) typeLookup[type].newInstance();
}
catch (Exception ex) {
throw new ExpressionException("Error creating expression", ex);
}
}
throw new ExpressionException("Bad expression type: " + type);
}
/**
* Applies a few default rules for adding operands to expressions. In particular wraps
* all lists into LIST expressions. Applied only in path expressions.
*/
protected static Object wrapPathOperand(Object op) {
if (op instanceof Collection) {
return new ASTList((Collection<?>) op);
}
else if (op instanceof Object[]) {
return new ASTList((Object[]) op);
}
else {
return op;
}
}
/**
* Creates an expression that matches any of the key-values pairs in <code>map</code>.
* <p>
* For each pair <code>pairType</code> operator is used to build a binary
* expression. Key is considered to be a DB_PATH expression. OR is used to join pair
* binary expressions.
*/
public static Expression matchAnyDbExp(Map<String, ?> map, int pairType) {
List<Expression> pairs = new ArrayList<Expression>(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
Expression exp = expressionOfType(pairType);
exp.setOperand(0, new ASTDbPath(entry.getKey()));
exp.setOperand(1, wrapPathOperand(entry.getValue()));
pairs.add(exp);
}
return joinExp(Expression.OR, pairs);
}
/**
* Creates an expression that matches all key-values pairs in <code>map</code>.
* <p>
* For each pair <code>pairType</code> operator is used to build a binary
* expression. Key is considered to be a DB_PATH expression. AND is used to join pair
* binary expressions.
*/
public static Expression matchAllDbExp(Map<String, ?> map, int pairType) {
List<Expression> pairs = new ArrayList<Expression>(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
Expression exp = expressionOfType(pairType);
exp.setOperand(0, new ASTDbPath(entry.getKey()));
exp.setOperand(1, wrapPathOperand(entry.getValue()));
pairs.add(exp);
}
return joinExp(Expression.AND, pairs);
}
/**
* Creates an expression that matches any of the key-values pairs in the
* <code>map</code>.
* <p>
* For each pair <code>pairType</code> operator is used to build a binary
* expression. Key is considered to be a OBJ_PATH expression. OR is used to join pair
* binary expressions.
*/
public static Expression matchAnyExp(Map<String, ?> map, int pairType) {
List<Expression> pairs = new ArrayList<Expression>(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
Expression exp = expressionOfType(pairType);
exp.setOperand(0, new ASTObjPath(entry.getKey()));
exp.setOperand(1, wrapPathOperand(entry.getValue()));
pairs.add(exp);
}
return joinExp(Expression.OR, pairs);
}
/**
* Creates an expression to match a collection of values against a single path
* expression.
* <h3>Splits</h3>
* <p>
* Note that "path" argument here can use a split character (a pipe symbol - '|')
* instead of dot to indicate that relationship following a path should be split into
* a separate set of joins. There can only be one split at most. Split must always
* precede a relationship. E.g. "|exhibits.paintings", "exhibits|paintings", etc.
*
* @param path
* @param values
* @since 3.0
*/
@SuppressWarnings("unchecked")
public static Expression matchAllExp(String path, Collection values) {
if (values == null) {
throw new NullPointerException("Null values collection");
}
if (values.size() == 0) {
return new ASTTrue();
}
return matchAllExp(path, values.toArray());
}
/**
* @since 3.0
*/
public static Expression matchAllExp(String path, Object... values) {
if (values == null) {
throw new NullPointerException("Null values collection");
}
if (values.length == 0) {
return new ASTTrue();
}
int split = path.indexOf(SPLIT_SEPARATOR);
List<Expression> matches = new ArrayList<Expression>(values.length);
if (split >= 0 && split < path.length() - 1) {
int splitEnd = path.indexOf(Entity.PATH_SEPARATOR, split + 1);
String beforeSplit = split > 0 ? path.substring(0, split) + "." : "";
String afterSplit = splitEnd > 0 ? "." + path.substring(splitEnd + 1) : "";
String aliasBase = "split" + autoAliasId++ + "_";
String splitChunk = splitEnd > 0 ? path.substring(split + 1, splitEnd) : path
.substring(split + 1);
// fix the path - replace split with dot if it's in the middle, or strip it if
// it's in the beginning
path = split == 0 ? path.substring(1) : path.replace(SPLIT_SEPARATOR, '.');
int i = 0;
for (Object value : values) {
String alias = aliasBase + i;
String aliasedPath = beforeSplit + alias + afterSplit;
i++;
ASTPath pathExp = new ASTObjPath(aliasedPath);
pathExp.setPathAliases(Collections.singletonMap(alias, splitChunk));
matches.add(new ASTEqual(pathExp, value));
}
}
else {
for (Object value : values) {
matches.add(new ASTEqual(new ASTObjPath(path), value));
}
}
return joinExp(Expression.AND, matches);
}
/**
* Creates an expression that matches all key-values pairs in <code>map</code>.
* <p>
* For each pair <code>pairType</code> operator is used to build a binary
* expression. Key is considered to be a OBJ_PATH expression. AND is used to join pair
* binary expressions.
*/
public static Expression matchAllExp(Map<String, ?> map, int pairType) {
List<Expression> pairs = new ArrayList<Expression>(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
Expression exp = expressionOfType(pairType);
exp.setOperand(0, new ASTObjPath(entry.getKey()));
exp.setOperand(1, wrapPathOperand(entry.getValue()));
pairs.add(exp);
}
return joinExp(Expression.AND, pairs);
}
/**
* A convenience method to create an DB_PATH "equal to" expression.
*/
public static Expression matchDbExp(String pathSpec, Object value) {
return new ASTEqual(new ASTDbPath(pathSpec), value);
}
/**
* A convenience method to create an DB_PATH "not equal to" expression.
*/
public static Expression noMatchDbExp(String pathSpec, Object value) {
return new ASTNotEqual(new ASTDbPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "equal to" expression.
*/
public static Expression matchExp(String pathSpec, Object value) {
return new ASTEqual(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "not equal to" expression.
*/
public static Expression noMatchExp(String pathSpec, Object value) {
return new ASTNotEqual(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "less than" expression.
*/
public static Expression lessExp(String pathSpec, Object value) {
return new ASTLess(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an DB_PATH "less than" expression.
*
* @since 3.0
*/
public static Expression lessDbExp(String pathSpec, Object value) {
return new ASTLess(new ASTDbPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "less than or equal to" expression.
*/
public static Expression lessOrEqualExp(String pathSpec, Object value) {
return new ASTLessOrEqual(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an DB_PATH "less than or equal to" expression.
*
* @since 3.0
*/
public static Expression lessOrEqualDbExp(String pathSpec, Object value) {
return new ASTLessOrEqual(new ASTDbPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "greater than" expression.
*/
public static Expression greaterExp(String pathSpec, Object value) {
return new ASTGreater(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an DB_PATH "greater than" expression.
*
* @since 3.0
*/
public static Expression greaterDbExp(String pathSpec, Object value) {
return new ASTGreater(new ASTDbPath(pathSpec), value);
}
/**
* A convenience method to create an OBJ_PATH "greater than or equal to" expression.
*/
public static Expression greaterOrEqualExp(String pathSpec, Object value) {
return new ASTGreaterOrEqual(new ASTObjPath(pathSpec), value);
}
/**
* A convenience method to create an DB_PATH "greater than or equal to" expression.
*
* @since 3.0
*/
public static Expression greaterOrEqualDbExp(String pathSpec, Object value) {
return new ASTGreaterOrEqual(new ASTDbPath(pathSpec), value);
}
/**
* A convenience shortcut for building IN expression. Return ASTFalse for empty
* collection.
*/
public static Expression inExp(String pathSpec, Object... values) {
if (values.length == 0) {
return new ASTFalse();
}
return new ASTIn(new ASTObjPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building IN DB expression. Return ASTFalse for empty
* collection.
*/
public static Expression inDbExp(String pathSpec, Object... values) {
if (values.length == 0) {
return new ASTFalse();
}
return new ASTIn(new ASTDbPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building IN expression. Return ASTFalse for empty
* collection.
*/
public static Expression inExp(String pathSpec, Collection<?> values) {
if (values.isEmpty()) {
return new ASTFalse();
}
return new ASTIn(new ASTObjPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building IN DB expression. Return ASTFalse for empty
* collection.
*/
public static Expression inDbExp(String pathSpec, Collection<?> values) {
if (values.isEmpty()) {
return new ASTFalse();
}
return new ASTIn(new ASTDbPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building NOT_IN expression. Return ASTTrue for empty
* collection.
*/
public static Expression notInExp(String pathSpec, Collection<?> values) {
if (values.isEmpty()) {
return new ASTTrue();
}
return new ASTNotIn(new ASTObjPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building NOT_IN expression. Return ASTTrue for empty
* collection.
*
* @since 3.0
*/
public static Expression notInDbExp(String pathSpec, Collection<?> values) {
if (values.isEmpty()) {
return new ASTTrue();
}
return new ASTNotIn(new ASTDbPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building NOT_IN expression. Return ASTTrue for empty
* collection.
*
* @since 1.0.6
*/
public static Expression notInExp(String pathSpec, Object... values) {
if (values.length == 0) {
return new ASTTrue();
}
return new ASTNotIn(new ASTObjPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building NOT_IN expression. Return ASTTrue for empty
* collection.
*
* @since 3.0
*/
public static Expression notInDbExp(String pathSpec, Object... values) {
if (values.length == 0) {
return new ASTTrue();
}
return new ASTNotIn(new ASTDbPath(pathSpec), new ASTList(values));
}
/**
* A convenience shortcut for building BETWEEN expressions.
*/
public static Expression betweenExp(String pathSpec, Object value1, Object value2) {
return new ASTBetween(new ASTObjPath(pathSpec), value1, value2);
}
/**
* A convenience shortcut for building BETWEEN expressions.
*
* @since 3.0
*/
public static Expression betweenDbExp(String pathSpec, Object value1, Object value2) {
return new ASTBetween(new ASTDbPath(pathSpec), value1, value2);
}
/**
* A convenience shortcut for building NOT_BETWEEN expressions.
*/
public static Expression notBetweenExp(String pathSpec, Object value1, Object value2) {
return new ASTNotBetween(new ASTObjPath(pathSpec), value1, value2);
}
/**
* A convenience shortcut for building NOT_BETWEEN expressions.
*
* @since 3.0
*/
public static Expression notBetweenDbExp(String pathSpec, Object value1, Object value2) {
return new ASTNotBetween(new ASTDbPath(pathSpec), value1, value2);
}
/**
* A convenience shortcut for building LIKE expression.
*/
public static Expression likeExp(String pathSpec, Object value) {
return new ASTLike(new ASTObjPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building LIKE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression likeExp(String pathSpec, Object value, char escapeChar) {
return new ASTLike(new ASTObjPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building LIKE DB_PATH expression.
*
* @since 3.0
*/
public static Expression likeDbExp(String pathSpec, Object value) {
return new ASTLike(new ASTDbPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building LIKE DB_PATH expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression likeDbExp(String pathSpec, Object value, char escapeChar) {
return new ASTLike(new ASTDbPath(pathSpec), value,escapeChar);
}
/**
* A convenience shortcut for building NOT_LIKE expression.
*/
public static Expression notLikeExp(String pathSpec, Object value) {
return new ASTNotLike(new ASTObjPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building NOT_LIKE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression notLikeExp(String pathSpec, Object value, char escapeChar) {
return new ASTNotLike(new ASTObjPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building NOT_LIKE expression.
*
* @since 3.0
*/
public static Expression notLikeDbExp(String pathSpec, Object value) {
return new ASTNotLike(new ASTDbPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building NOT_LIKE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression notLikeDbExp(String pathSpec, Object value, char escapeChar) {
return new ASTNotLike(new ASTDbPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building LIKE_IGNORE_CASE expression.
*/
public static Expression likeIgnoreCaseExp(String pathSpec, Object value) {
return new ASTLikeIgnoreCase(new ASTObjPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building LIKE_IGNORE_CASE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression likeIgnoreCaseExp(String pathSpec, Object value, char escapeChar) {
return new ASTLikeIgnoreCase(new ASTObjPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building LIKE_IGNORE_CASE expression.
*
* @since 3.0
*/
public static Expression likeIgnoreCaseDbExp(String pathSpec, Object value) {
return new ASTLikeIgnoreCase(new ASTDbPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building LIKE_IGNORE_CASE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression likeIgnoreCaseDbExp(String pathSpec, Object value, char escapeChar) {
return new ASTLikeIgnoreCase(new ASTDbPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building NOT_LIKE_IGNORE_CASE expression.
*/
public static Expression notLikeIgnoreCaseExp(String pathSpec, Object value) {
return new ASTNotLikeIgnoreCase(new ASTObjPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building NOT_LIKE_IGNORE_CASE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression notLikeIgnoreCaseExp(String pathSpec, Object value, char escapeChar) {
return new ASTNotLikeIgnoreCase(new ASTObjPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for building NOT_LIKE_IGNORE_CASE expression.
*
* @since 3.0
*/
public static Expression notLikeIgnoreCaseDbExp(String pathSpec, Object value) {
return new ASTNotLikeIgnoreCase(new ASTDbPath(pathSpec), value);
}
/**
* <p>A convenience shortcut for building NOT_LIKE_IGNORE_CASE expression.</p>
*
* <p>The escape character allows for escaping meta-characters
* in the LIKE clause. Note that the escape character cannot
* be '?'. To specify no escape character, supply 0 as the
* escape character.</p>
*
* @since 3.0.1
*/
public static Expression notLikeIgnoreCaseDbExp(String pathSpec, Object value, char escapeChar) {
return new ASTNotLikeIgnoreCase(new ASTDbPath(pathSpec), value, escapeChar);
}
/**
* A convenience shortcut for boolean true expression.
*
* @since 3.0
*/
public static Expression expTrue() {
return new ASTTrue();
}
/**
* A convenience shortcut for boolean false expression.
*
* @since 3.0
*/
public static Expression expFalse() {
return new ASTFalse();
}
/**
* Joins all <code>expressions</code> in a single expression. <code>type</code> is
* used as an expression type for expressions joining each one of the items on the
* list. <code>type</code> must be binary expression type.
* <p>
* For example, if type is Expression.AND, resulting expression would match all
* expressions in the list. If type is Expression.OR, resulting expression would match
* any of the expressions.
* </p>
*/
public static Expression joinExp(int type, List<Expression> expressions) {
int len = expressions.size();
if (len == 0)
return null;
Expression currentExp = expressions.get(0);
if (len == 1) {
return currentExp;
}
Expression exp = expressionOfType(type);
for (int i = 0; i < len; i++) {
exp.setOperand(i, expressions.get(i));
}
return exp;
}
/**
* Creates an expression that matches the primary key of object in
* <code>ObjectId</code>'s <code>IdSnapshot</code> for the argument
* <code>object</code>.
*/
public static Expression matchExp(Persistent object) {
return matchAllDbExp(object.getObjectId().getIdSnapshot(), Expression.EQUAL_TO);
}
/**
* Creates an expression that matches any of the objects contained in the list
* <code>objects</code>
*/
public static Expression matchAnyExp(List<? extends Persistent> objects) {
if (objects == null || objects.size() == 0) {
return expFalse();
}
return matchAnyExp(objects.toArray(new Persistent[objects.size()]));
}
/**
* Creates an expression that matches any of the objects contained in the
* <code>objects</code> array
*/
public static Expression matchAnyExp(Persistent... objects) {
if (objects == null || objects.length == 0) {
return expFalse();
}
List<Expression> pairs = new ArrayList<Expression>(objects.length);
for (Persistent object : objects) {
pairs.add(matchExp(object));
}
return joinExp(Expression.OR, pairs);
}
}