/*
* $Header: /home/cvspublic/jakarta-commons/jxpath/src/java/org/apache/commons/jxpath/ri/axes/UnionContext.java,v 1.7 2002/05/29 00:41:32 dmitri Exp $
* $Revision: 1.7 $
* $Date: 2002/05/29 00:41:32 $
*
* ====================================================================
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999-2001 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
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*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 2001, Plotnix, Inc,
* <http://www.plotnix.com/>.
* For more information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.commons.jxpath.ri.axes;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.model.NodePointer;
/**
* EvalContext that represents a union between other contexts - result
* of a union operation like (a | b)
*
* @author Dmitri Plotnikov
* @version $Revision: 1.7 $ $Date: 2002/05/29 00:41:32 $
*/
public class UnionContext extends EvalContext {
private boolean startedSet = false;
private EvalContext contexts[];
private List list;
public UnionContext(EvalContext parentContext, EvalContext contexts[]){
super(parentContext);
this.contexts = contexts;
}
public int getDocumentOrder(){
if (contexts.length > 1){
return 1;
}
return super.getDocumentOrder();
}
public NodePointer getCurrentNodePointer(){
if (position == 0){
if (!setPosition(1)){
return null;
}
}
return (NodePointer)list.get(position - 1);
}
public boolean setPosition(int position){
super.setPosition(position);
if (list == null){
prepareList();
}
return position >= 1 && position <= list.size();
}
public boolean nextSet(){
if (startedSet){
return false;
}
startedSet = true;
return true;
}
public boolean nextNode(){
return setPosition(position + 1);
}
private void prepareList(){
list = new ArrayList();
HashSet set = new HashSet();
for (int i = 0; i < contexts.length; i++){
EvalContext ctx = (EvalContext)contexts[i];
while (ctx.nextSet()){
while (ctx.nextNode()){
NodePointer ptr = ctx.getCurrentNodePointer();
if (!set.contains(ptr)){
ptr = (NodePointer)ptr.clone();
list.add(ptr);
set.add(ptr);
}
}
}
}
}
}