org.apache.slide.search.basic.expression
Class MergeExpression

java.lang.Object
  org.apache.slide.search.basic.expression.BasicExpression
      org.apache.slide.search.basic.expression.GenericBasicExpression
          org.apache.slide.search.basic.expression.MergeExpression

All Implemented Interfaces:

IBasicExpression

Direct Known Subclasses:

AndExpression, OrExpression

public abstract class MergeExpression

extends GenericBasicExpression

Abstract base class for merge expressions (AND, OR).

Version:

$Revision: 1.2.2.1 $

Author:

Martin Wallmer

Field Summary

protected BasicExpressionFactory	expressionFactory
protected java.util.Collection	expressionsToMerge all nested expressions

Fields inherited from class org.apache.slide.search.basic.expression.BasicExpression

expressionElement, resultSet

Constructor Summary

(package private)

MergeExpression(org.jdom.Element e, java.util.Collection expressionsToMerge) Creates a merge expression according to Element e

Method Summary

IBasicResultSet	execute() Executes the expression.
java.util.Collection	getExpressionsToMerge() Returns the expressions to merge.
static java.lang.String	getMustHaveMergeExpressionsMessage(java.lang.String operationName) Returns the message of the InvalidQueryException that is thrown by the constructor the expressionsToMerge set is empty.
protected abstract void	merge(IBasicResultSet set) Merges the given set into the result Set of this expression.
protected java.lang.String	toString(java.lang.String op) String representation for debugging purposes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

expressionsToMerge

protected java.util.Collection expressionsToMerge

all nested expressions

expressionFactory

protected BasicExpressionFactory expressionFactory

Constructor Detail

MergeExpression

MergeExpression(org.jdom.Element e,
                java.util.Collection expressionsToMerge)
          throws InvalidQueryException

Creates a merge expression according to Element e

Parameters:

e - jdom element, that describes the expression

expressionsToMerge - a Collection of IBasicExpressions to merge.

Method Detail

getExpressionsToMerge

public java.util.Collection getExpressionsToMerge()

Returns the expressions to merge.

Returns:

the expressions to merge.

execute

public IBasicResultSet execute()
                        throws SearchException

Executes the expression.

Returns:

a Set of RequestedResource objects

Throws:

SearchException

merge

protected abstract void merge(IBasicResultSet set)

Merges the given set into the result Set of this expression.

Parameters:

set - the Set to merge.

toString

protected java.lang.String toString(java.lang.String op)

String representation for debugging purposes.

Returns:

this expression as String

getMustHaveMergeExpressionsMessage

public static java.lang.String getMustHaveMergeExpressionsMessage(java.lang.String operationName)

Returns the message of the InvalidQueryException that is thrown by the constructor the expressionsToMerge set is empty.

Parameters:

operationName - the name of the operation (e.g. and)

Returns:

the message of the InvalidQueryException.