/*
* Licensed to the Apache Software Foundation (ASF) under one
* 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
* under the License.
*/
package org.apache.empire.db;
// java
import org.apache.empire.commons.Attributes;
import org.apache.empire.commons.OptionEntry;
import org.apache.empire.commons.Options;
import org.apache.empire.commons.StringUtils;
import org.apache.empire.data.Column;
import org.apache.empire.data.ColumnExpr;
import org.apache.empire.data.DataType;
import org.apache.empire.db.expr.column.DBAliasExpr;
import org.apache.empire.db.expr.column.DBCalcExpr;
import org.apache.empire.db.expr.column.DBCaseExpr;
import org.apache.empire.db.expr.column.DBConcatExpr;
import org.apache.empire.db.expr.column.DBConvertExpr;
import org.apache.empire.db.expr.column.DBCountExpr;
import org.apache.empire.db.expr.column.DBDecodeExpr;
import org.apache.empire.db.expr.column.DBFuncExpr;
import org.apache.empire.db.expr.column.DBValueExpr;
import org.apache.empire.db.expr.compare.DBCompareColExpr;
import org.apache.empire.db.expr.compare.DBCompareExpr;
import org.apache.empire.db.expr.order.DBOrderByExpr;
import org.w3c.dom.Element;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
/**
* This class is the base class for all expressions that represent a single value.
* It provides a set of factory functions for SQL functions.
*/
public abstract class DBColumnExpr extends DBExpr
implements ColumnExpr
{
private final static long serialVersionUID = 1L;
// Predefined column expression attributes
public static final String DBCOLATTR_TITLE = "title";
public static final String DBCOLATTR_TYPE = "type";
// Properties
protected Attributes attributes = null;
protected Options options = null;
protected String beanPropertyName = null;
/**
* Returns the data type of this column expression.
* @see org.apache.empire.data.DataType
*
* @return the expressions data type
*/
public abstract DataType getDataType();
/**
* Returns the column name for this column expression.
* The name must contain only alphanumeric characters and the underscore.
* For SQL functions this name may be generated. However subsequent calls to this function
* for the same object instance must return the same string.
*
* @return the column name
*/
public abstract String getName();
/**
* Indicates wheter this function is an aggregate (sum, min, max, avg, ...) or not
* @return true if the column expression represents an aggregate
*/
public abstract boolean isAggregate();
/**
* Returns the underlying physical column which may be used for updates.
* For functions involving none or more than one physical column this function returns null.
* @return the column to be used for updates if any.
*/
public abstract DBColumn getUpdateColumn();
/**
* Add a description of this column with relevant metadata
* to the supplied parent XML Element.
*
* @param parent the parent element to which to append the column description
* @param flags currently not used
* @return the newly created child element
*/
public abstract Element addXml(Element parent, long flags);
/**
* Returns the value of a column attribute.
* Column attributes are used to provide metadata for a column.
*
* @param name the attribute name
* @return value of the attribute if it exists or null otherwise
*/
public synchronized Object getAttribute(String name)
{
if (attributes != null && attributes.contains(name))
return attributes.get(name);
// Otherwise ask expression
DBColumn column = getUpdateColumn();
if (column==null || column==this)
return null;
return column.getAttribute(name);
}
/**
* Sets the value of a column attribute.
*
* @param name the attribute name
* @param value the value of the attribute
*/
public synchronized void setAttribute(String name, Object value)
{
if (attributes== null)
attributes = new Attributes();
attributes.set(name, value);
}
/**
* Returns the list of options for this column
* containing all possible field values.
*
* @return the list of options
*/
public synchronized Options getOptions()
{
if (options != null)
return options;
// Otherwise ask expression
DBColumn column = getUpdateColumn();
if (column==null || column==this)
return null;
return column.getOptions();
}
/**
* Sets the options for this column indicating all valid values.
*
* @param options the list of options
*/
public synchronized void setOptions(Options options)
{
this.options = options;
}
/**
* Returns the title attribute.
*
* @return the column title
*/
public final String getTitle()
{
Object title = getAttribute(DBCOLATTR_TITLE);
return StringUtils.toString(title);
}
/**
* Sets the title attribute.
*
* @param title the column title
*/
public final void setTitle(String title)
{
setAttribute(DBCOLATTR_TITLE, title);
}
/**
* Returns the column control type.
* The control type is a client specific name for the type of input control
* that should be used to display and edit values for this column.
*
* @return the column control type
*/
public final String getControlType()
{
Object type = getAttribute(DBCOLATTR_TYPE);
return StringUtils.toString(type);
}
/**
* Sets the controlType attribute.
*
* @param controlType the column control type
*/
public final void setControlType(String controlType)
{
setAttribute(DBCOLATTR_TYPE, controlType);
}
/**
* Returns the source column.
* This is equivalent to the "Update Column"
* see getUpdateColumn()
*/
public final Column getSourceColumn()
{
return getUpdateColumn();
}
/**
* Gets the Java bean property name for this column
* i.e. ID = employeeId
* DATE_OF_BIRTH = dateOfBirth
*
* @return the name of the bean property used to get and set values
*/
public String getBeanPropertyName()
{
if (beanPropertyName==null)
{ // Compute bean property name
String name = getName();
if (name==null)
return null; // no name provided!
// compute name
name = name.toLowerCase();
String res = "";
int beg=0;
while (beg<name.length())
{
int end = name.indexOf('_', beg);
if (end<0)
end = name.length();
// assemble
if (end>beg)
{
if (beg==0)
{ // begin with all lower cases
res = name.substring(beg, end);
}
else
{ // add word where first letter is upper case
res += name.substring(beg, beg+1).toUpperCase();
if (end-beg>1)
{
res += name.substring(beg+1, end);
}
}
}
// next
beg = end + 1;
}
// Result
beanPropertyName = res;
}
return beanPropertyName;
}
/**
* Sets the Java bean property name for this column.
*
* @param propertyName
*/
public void setBeanPropertyName(String propertyName)
{
this.beanPropertyName = propertyName;
}
/**
* Creates a new DBConcatExpr object with the specified value.
*
* @param value an Object value
* @return the new DBConcatExpr object
*/
public DBColumnExpr append(Object value)
{
return new DBConcatExpr(this, value);
}
/**
* creates a new DBAliasExpr which renames the current expression to the supplied name.
* <P>
* @param alias the alias name
* @return the new DBAliasExpr object
*/
public DBColumnExpr as(String alias)
{
return new DBAliasExpr(this, alias);
}
/**
* creates a new DBAliasExpr which renames the current expression to the name of the supplied column.
* <P>
* @param column the column whose name serves as an alias for the current expression
* @return the new DBAliasExpr object
*/
public DBColumnExpr as(DBColumn column)
{
return new DBAliasExpr(this, column.getName());
}
/**
* Creates and returns a new comparison object for the given comparison operator and value.
*
* @param op the comparison operator
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr cmp(DBCmpType op, Object value)
{
return new DBCompareColExpr(this, op, value);
}
/**
* Creates and returns a new comparison object for the SQL "like" operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr like(Object value)
{
return cmp(DBCmpType.LIKE, value);
}
/**
* Creates and returns a new comparison object for the SQL "like" operator.
* By converting column value and comparison value to upper case
* the like is effectively case insensitive.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr likeUpper(String value)
{
DBValueExpr expr = new DBValueExpr(getDatabase(), value, DataType.TEXT);
return new DBCompareColExpr(this.upper(), DBCmpType.LIKE, expr.upper());
}
/**
* Creates and returns a new comparison object for the SQL "like" operator.
* By converting column value and comparison value to lower case
* the like is effectively case insensitive.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr likeLower(String value)
{
DBValueExpr expr = new DBValueExpr(getDatabase(), value, DataType.TEXT);
return new DBCompareColExpr(this.lower(), DBCmpType.LIKE, expr.lower());
}
/**
* Creates and returns a new comparison object for the SQL "like" operator.
*
* @param value the Object value
* @param escape the escape character
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr like(String value, char escape)
{
DBValueExpr textExpr = new DBValueExpr(getDatabase(), value, DataType.TEXT);
DBFuncExpr escapeExpr = new DBFuncExpr(textExpr, DBDatabaseDriver.SQL_FUNC_ESCAPE, new Object[] { String.valueOf(escape) }, getUpdateColumn(), false, DataType.TEXT );
return cmp(DBCmpType.LIKE, escapeExpr);
}
/**
* Creates and returns a new comparison object for the SQL "not like" operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr notLike(Object value)
{
return cmp(DBCmpType.NOTLIKE, value);
}
/**
* Creates and returns a new comparison object for the SQL "=" (equal) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr is(Object value)
{
return cmp(DBCmpType.EQUAL, value);
}
/**
* Creates and returns a new comparison object
* for the SQL "<>" (not equal) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isNot(Object value)
{
return cmp(DBCmpType.NOTEQUAL, value);
}
/**
* Creates and returns a new comparison object
* for the SQL "in" operator.
*
* @param value the int value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr in(Object value)
{
return cmp(DBCmpType.IN, listToArray(value));
}
/**
* Creates and returns a new comparison object
* for the SQL "not in" operator.
*
* @param value the int value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr notIn(Object value)
{
return cmp(DBCmpType.NOTIN, listToArray(value));
}
/**
* Creates and returns a new comparison object
* for the SQL "between" operator.
*
* @param minValue the minimum value
* @param maxValue the maximum value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isBetween(Object minValue, Object maxValue)
{
return cmp(DBCmpType.BETWEEN, new Object[] { minValue, maxValue });
}
/**
* Creates and returns a new comparison object
* for the SQL "not between" operator.
*
* @param minValue the minimum value
* @param maxValue the maximum value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isNotBetween(Object minValue, Object maxValue)
{
return cmp(DBCmpType.NOTBETWEEN, new Object[] { minValue, maxValue });
}
/**
* Creates and returns a new comparison object
* for the SQL ">" (greater than) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isGreaterThan(Object value)
{
return cmp(DBCmpType.GREATERTHAN, value);
}
/**
* Creates and returns a new comparison object
* for the SQL ">=" (greater or equal) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isMoreOrEqual(Object value)
{
return cmp(DBCmpType.MOREOREQUAL, value);
}
/**
* Creates and returns a new comparison object
* for the SQL "<=" (less or equal) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isLessOrEqual(Object value)
{
return cmp(DBCmpType.LESSOREQUAL, value);
}
/**
* Creates and returns a new comparison object
* for the SQL "<" (less than) operator.
*
* @param value the Object value
* @return the new DBCompareColExpr object
*/
public DBCompareColExpr isSmallerThan(Object value)
{
return cmp(DBCmpType.LESSTHAN, value);
}
// ------- calculations -------
/**
* Creates and returns a new calculation object
* for the SQL "*" (multiply) operator.
*
* @param value the multiply value
* @return the new DBCalcExpr object
*/
public DBCalcExpr multiplyWith(Object value)
{
return new DBCalcExpr(this, "*", value);
}
/**
* Creates and returns a new calculation object
* for the SQL "/" (divide) operator.
*
* @param value the divide value
* @return the new DBCalcExpr object
*/
public DBCalcExpr divideBy(Object value)
{
return new DBCalcExpr(this, "/", value);
}
/**
* Creates and returns a new calculation object
* for the SQL "+" (plus) operator.
*
* @param value the summate value
* @return the new DBCalcExpr object
*/
public DBCalcExpr plus(Object value)
{
return new DBCalcExpr(this, "+", value);
}
/**
* Creates and returns a new calculation object
* for the SQL "-" (minus) operator.
*
* @param value the subtract value
* @return the new DBCalcExpr object
*/
public DBCalcExpr minus(Object value)
{
return new DBCalcExpr(this, "-", value);
}
/**
* Creates and returns a new calculation object
* for either the SQL "+" (plus) or "-" (minus) operator
* depending on whether the supplied integer value is positive or negative.
*
* @param value the subtract value
* @return the new DBCalcExpr object
*/
public DBCalcExpr plus(int value)
{
return (value >= 0) ? new DBCalcExpr(this, "+", new Integer(value)) : new DBCalcExpr(this, "-", new Integer(-value));
}
/**
* Creates and returns a new calculation object
* for either the SQL "+" (plus) or "-" (minus) operator
* depending on whether the supplied integer value is negative or positive.
*
* @param value the subtract value
* @return the new DBCalcExpr object
*/
public DBCalcExpr minus(int value)
{
return (value >= 0) ? new DBCalcExpr(this, "-", new Integer(value)) : new DBCalcExpr(this, "+", new Integer(-value));
}
// ----------------------------------------------------------
// --------------------- DBFuncExpr -------------------------
// ----------------------------------------------------------
/**
* Creates a new DBFuncExpr from a given SQL-PRHASE and
* optional additional parameters.
*
* @param phrase the id of the SQL-phrase
* @param params the params to replace in the template
* @param isAggregate indicates whether the Function creates an aggregate
* @param dataType the resulting data Type
* @return the new DBCalcExpr object
*/
protected DBColumnExpr getExprFromPhrase(int phrase, Object[] params, DBColumn updateColumn, boolean isAggregate, DataType dataType)
{
return new DBFuncExpr(this, phrase, params, updateColumn, isAggregate, dataType);
}
protected DBColumnExpr getExprFromPhrase(int phrase, Object[] params, DBColumn updateColumn, boolean isAggregate)
{
return getExprFromPhrase(phrase, params, updateColumn, isAggregate, getDataType());
}
/**
* Creates and returns a function object which
* encloses the current expression in parenthesis.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr parenthesis()
{
return new DBFuncExpr(this, "(?)", null, getUpdateColumn(), false, getDataType());
}
/**
* Creates a sql-expression for the nvl() or coalesce() function.
*
* @param nullValue the Object value
* @return the new DBFuncExpr object
*/
public DBColumnExpr coalesce(Object nullValue)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_COALESCE, new Object[] { nullValue }, getUpdateColumn(), false);
}
/**
* Creates a sql-expression for the nvl() or coalesce() function.
*
* @param nullValue the int value
* @return the new DBFuncExpr object
*
* @deprecated Outdated oracle syntax - use coalesce instead
*/
@Deprecated
public DBColumnExpr nvl(Object nullValue)
{
return coalesce(nullValue);
}
/**
* Creates and returns a sql-expression for the substring(...) function.
*
* @param pos the position number of the string
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(DBExpr pos)
{ // Get Expression
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_SUBSTRING, new Object[] { pos }, getUpdateColumn(), false);
}
/**
* Overloaded. @see substring(DBExpr pos)
*
* @param pos the position number of the string
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(int pos)
{
return substring(new DBValueExpr(getDatabase(), pos, DataType.INTEGER));
}
/**
* Creates and returns a sql-expression for the substring(...) function.
*
* @param pos the position number of the string
* @param count the length of the substring
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(DBExpr pos, DBExpr count)
{ // Get Expression
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_SUBSTRINGEX, new Object[] { pos, count }, getUpdateColumn(), false);
}
/**
* Overloaded. @see substring(DBExpr pos, DBExpr count)
*
* @param pos the position number of the string
* @param count the length of the substring
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(DBExpr pos, int count)
{
return substring(pos, new DBValueExpr(getDatabase(), count, DataType.INTEGER));
}
/**
* Overloaded. @see substring(DBExpr pos, DBExpr count)
*
* @param pos the position number of the string
* @param count the length of the substring
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(int pos, DBExpr count)
{
return substring(new DBValueExpr(getDatabase(), pos, DataType.INTEGER), count);
}
/**
* Overloaded. @see substring(DBExpr pos, DBExpr count)
*
* @param pos the position number of the string
* @param count the length of the substring
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr substring(int pos, int count)
{
return substring(new DBValueExpr(getDatabase(), pos, DataType.INTEGER),
new DBValueExpr(getDatabase(), count, DataType.INTEGER));
}
/**
* Creates and returns a sql-expression for the replace(...) function.
*
* @param match string to replace
* @param replace string with replacement
* @return the new DBFuncExpr object
*/
public DBColumnExpr replace(Object match, Object replace)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_REPLACE, new Object[] { match, replace }, getUpdateColumn(), false);
}
/**
* Creates and returns a sql-expression for the reverse(...) function.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr reverse()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_REVERSE, null, getUpdateColumn(), false);
}
/**
* Creates and returns a sql-expression for the trim() function.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr trim()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_TRIM, null, getUpdateColumn(), false);
}
/**
* Creates and returns a sql-expression for the ltrim() function.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr trimLeft()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_LTRIM, null, getUpdateColumn(), false);
}
/**
* Creates and returns a sql-expression for the rtrim() function.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr trimRight()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_RTRIM, null, getUpdateColumn(), false);
}
/**
* Creates and returns a function object which
* converts the current expression to upper case.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr upper()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_UPPER, null, getUpdateColumn(), false);
}
/**
* Creates and returns a function object which
* converts the current expression to lower case.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr lower()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_LOWER, null, getUpdateColumn(), false);
}
/**
* Creates and returns a sql-expression that returns the string length of this expression.
* @return the new DBFuncExpr object
*/
public DBColumnExpr length()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_LENGTH, null, getUpdateColumn(), false, DataType.INTEGER);
}
/**
* Creates and returns a sql-expression that returns the position of a string in the current column expression.
*
* @param str the string to find the position of
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr indexOf(Object str)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_STRINDEX, new Object[] { str }, getUpdateColumn(), false, DataType.INTEGER);
}
/**
* Creates and returns a sql-expression that returns the position of a string in the current column expression.
*
* @param str the string to find the position of
* @param fromPos the start position for the search
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr indexOf(Object str, DBExpr fromPos)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_STRINDEXFROM, new Object[] { str, fromPos }, getUpdateColumn(), false, DataType.INTEGER);
}
/**
* Overloaded. @see indexOf(Object str, DBExpr fromPos)
*
* @param str the string to find the position of
* @param fromPos the start position for the search
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr indexOf(Object str, int fromPos)
{
return indexOf(str, new DBValueExpr(getDatabase(), fromPos, DataType.INTEGER));
}
/**
* Creates and returns a sql-expression for the absolute abs() function.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr abs()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_ABS, null, getUpdateColumn(), false);
}
/**
* Creates and returns an function object that
* rounds a number espression with the given decimals.
*
* @param decimals the number of decimal to which to truncate the current value
* @return the new DBFuncExpr object
*/
public DBColumnExpr round(int decimals)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_ROUND, new Object[] { new Integer(decimals) }, getUpdateColumn(), false);
}
/**
* Creates and returns an function object that
* truncates a number espression with the given decimals.
*
* @param decimals the number of decimal to which to truncate the current value
* @return the new DBFuncExpr object
*/
public DBColumnExpr trunc(int decimals)
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_TRUNC, new Object[] { new Integer(decimals) }, getUpdateColumn(), false);
}
/**
* Creates and returns an function object that
* calculates the year of a date value.
*
* @return the new DBColumnExpr object
*/
public DBColumnExpr year()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_YEAR, null, null, false);
}
/**
* Creates and returns an function object that
* calculates the month of a date value.
*
* @return the new DBColumnExpr object
*/
public DBColumnExpr month()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_MONTH, null, null, false);
}
/**
* Creates and returns an function object that
* calculates the day of a date value.
*
* @return the new DBColumnExpr object
*/
public DBColumnExpr day()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_DAY, null, null, false);
}
/**
* Creates and returns an aggregation function object
* which calculates the sum for the current expression over a group of rows.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr sum()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_SUM, null, null, true);
}
/**
* Creates and returns an aggregation function object
* which returns the minimum value for the current expression over a group of rows.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr min()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_MIN, null, null, true);
}
/**
* Creates and returns an aggregation function object
* which returns the maximum value for the current expression over a group of rows.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr max()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_MAX, null, null, true);
}
/**
* Creates and returns an aggregation function object
* which returns the average value for the current expression over a group of rows.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr avg()
{
return getExprFromPhrase(DBDatabaseDriver.SQL_FUNC_AVG, null, null, true);
}
/**
* Creates and returns an expression for the SQL "count()" function
* which returns the number of rows in the result set.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr count()
{
return new DBCountExpr(this, false);
}
/**
* Creates and returns an expression for the SQL "count()" function
* which returns the number of unique values in the result set.
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr countDistinct()
{
return new DBCountExpr(this, true);
}
/**
* Detects the DataType of a given value.
* @param value the value to detect
* @return the DataType enum for the value
*/
protected DataType detectDataType(Object value)
{
if (value instanceof DBColumnExpr)
return ((DBColumnExpr)value).getDataType();
if (value instanceof String)
return DataType.TEXT;
if ((value instanceof Integer) || (value instanceof Long))
return DataType.INTEGER;
if (value instanceof Number)
return DataType.DECIMAL;
if (value instanceof Boolean)
return DataType.BOOL;
if (value instanceof Date)
return DataType.DATETIME;
if (value instanceof Character)
return DataType.CHAR;
if (value instanceof byte[])
return DataType.BLOB;
return DataType.UNKNOWN;
}
/**
* Creates and returns a sql-expression that compares the current column expression with
* a list of values and returns the corresponding alternative value.<BR>
*
* @param valueMap a list of key values pairs used for decoding
* @param otherwise the value to take if no key matches the given expression
* @return a DBDecodeExpr object
*/
public DBColumnExpr decode(Map<?,?> valueMap, Object otherwise)
{
// Detect data type
DataType dataType = DataType.UNKNOWN;
if (otherwise!=null)
{
dataType = detectDataType(otherwise);
}
if (dataType==DataType.UNKNOWN)
{
for (Object v : valueMap.values())
{
dataType = detectDataType(v);
if (dataType!=DataType.UNKNOWN)
break;
}
}
// Create the decode function
return new DBDecodeExpr(this, valueMap, otherwise, dataType);
}
public final DBColumnExpr decode(Object key1, Object value1, Object otherwise)
{
Map<Object, Object> list = new HashMap<Object, Object>();
list.put(key1, value1);
return decode(list, otherwise);
}
public final DBColumnExpr decode(Object key1, Object value1, Object key2, Object value2, Object otherwise)
{
Map<Object, Object> list = new HashMap<Object, Object>();
list.put(key1, value1);
list.put(key2, value2);
return decode(list, otherwise);
}
public final DBColumnExpr decode(Object key1, Object value1, Object key2, Object value2, Object key3, Object value3,
Object otherwise)
{
Map<Object, Object> list = new HashMap<Object, Object>();
list.put(key1, value1);
list.put(key2, value2);
list.put(key3, value3);
return decode(list, otherwise);
}
public final DBColumnExpr decode(Options options, Object otherwise)
{
int size = options.size() + (otherwise!=null ? 1 : 0);
Map<Object, Object> list = new HashMap<Object, Object>(size);
for (OptionEntry e : options)
list.put(e.getValue(), e.getText());
return decode(list, otherwise);
}
public final DBColumnExpr decode(Options options)
{
return decode(options, null);
}
/**
* Creates and returns a sql-expression for the SQL case-phrase.<BR/>
* The result will be in the form:<BR/>
* "case when [compExpr] then [this] else [otherwise] end"
*
* @param compExpr the condition for which the current column expression is returned
* @param otherwise the value that is returned if the condition is false
* @return a DBCaseExpr representing the SQL case phrase.
*/
public final DBCaseExpr when(DBCompareExpr compExpr, Object otherwise)
{
DBColumnExpr elseExpr = null;
if (otherwise instanceof DBColumnExpr)
{ // A column Expression
elseExpr = (DBColumnExpr)otherwise;
}
else if (otherwise != null)
{ // A constant value
elseExpr = new DBValueExpr(getDatabase(), otherwise, getDataType());
}
// Create DBCaseExpr
return new DBCaseExpr(compExpr, this, elseExpr);
}
// ----------------------------------------------------------
// --------------------- Conversion -------------------------
// ----------------------------------------------------------
/**
* Creates a new DBFuncExpr object (to_char SQL statement)
* with the parameters prefix = "to_char(" and postfix = ")"
*
* @return the new DBFuncExpr object
*/
public DBColumnExpr toChar()
{
return convertTo(DataType.TEXT);
}
/**
* Creates a new DBFuncExpr object (to_char SQL statement)
* with the parameters prefix = "to_char(" and postfix = ", *
* '"+format+"')"
*
* @param format the string value
* @return the new DBFuncExpr object
*/
public DBColumnExpr toChar(String format)
{
return convertTo(DataType.TEXT, format);
}
/**
* Creates a new DBFuncExpr object that will convert
* the current column to the destination data type specified.
*
* @param dataType the destination data type
* @param format optional destination format (usually a string)
* @return the new DBFuncExpr object
*/
public DBColumnExpr convertTo(DataType dataType, Object format)
{
return new DBConvertExpr(this, dataType, format);
}
/**
* Creates and returns a new DBFuncExpr object that will
* convert the current column to the destination data type specified.
*
* @param dataType Data type to which to convert the current expression to.
* @return the new DBFuncExpr object
*/
public final DBColumnExpr convertTo(DataType dataType)
{
return convertTo(dataType, null);
}
/**
* creates a new DBOrderByExpr for ascending order
* <P>
* @return the new DBOrderByExpr object for ascending order
*/
public DBOrderByExpr asc()
{
return new DBOrderByExpr(this, false);
}
/**
* creates a new DBOrderByExpr for descending order
* <P>
* @return the new DBOrderByExpr object for descending order
*/
public DBOrderByExpr desc()
{
return new DBOrderByExpr(this, true);
}
// get object Array from List
private Object listToArray(Object value)
{ // Check whether value is a list
/*
if (value != null && value instanceof java.util.List)
{ // Convert List to array
return ((List)value).toArray();
}
*/
return value;
}
}