/*
* $Header: /home/cvspublic/jakarta-commons/jxpath/src/java/org/apache/commons/jxpath/ri/axes/ChildContext.java,v 1.9 2002/05/14 23:08:26 dmitri Exp $
* $Revision: 1.9 $
* $Date: 2002/05/14 23:08:26 $
*
* ====================================================================
* 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
* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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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 org.apache.commons.jxpath.Pointer;
import org.apache.commons.jxpath.ri.EvalContext;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
/**
* EvalContext that can walk the "child::", "following-sibling::" and
* "preceding-sibling::" axes.
*
* @author Dmitri Plotnikov
* @version $Revision: 1.9 $ $Date: 2002/05/14 23:08:26 $
*/
public class ChildContext extends EvalContext {
private NodeTest nodeTest;
private boolean startFromParentLocation;
private boolean reverse;
private NodeIterator iterator;
public ChildContext(EvalContext parentContext, NodeTest nodeTest, boolean startFromParentLocation, boolean reverse){
super(parentContext);
this.nodeTest = nodeTest;
this.startFromParentLocation = startFromParentLocation;
this.reverse = reverse;
}
public NodePointer getCurrentNodePointer(){
if (position == 0){
if (!setPosition(1)){
return null;
}
}
if (iterator != null){
return iterator.getNodePointer();
}
else {
return null;
}
}
/**
* This method is called on the last context on the path when only
* one value is needed. Note that this will return the whole property,
* even if it is a collection. It will not extract the first element
* of the collection. For example, "books" will return the collection
* of books rather than the first book from that collection.
*/
public Pointer getSingleNodePointer(){
if (position == 0){
while(nextSet()){
prepare();
if (iterator == null){
return null;
}
// See if there is a property there, singular or collection
NodePointer pointer = iterator.getNodePointer();
if (pointer != null){
return pointer;
}
}
}
return getCurrentNodePointer();
}
public boolean nextNode(){
return setPosition(getCurrentPosition() + 1);
}
public void reset(){
super.reset();
iterator = null;
}
public boolean setPosition(int position){
int oldPosition = getCurrentPosition();
super.setPosition(position);
if (oldPosition == 0){
prepare();
}
if (iterator == null){
return false;
}
return iterator.setPosition(position);
}
/**
* Allocates a PropertyIterator.
*/
private void prepare(){
NodePointer parent = parentContext.getCurrentNodePointer();
if (parent == null){
return;
}
if (startFromParentLocation){
NodePointer pointer = parent.getParent();
while (pointer != null && !pointer.isNode()){
pointer = pointer.getParent();
}
iterator = pointer.childIterator(nodeTest, reverse, parent);
}
else {
iterator = parent.childIterator(nodeTest, reverse, null);
}
}
}