cachednodelistiterator.java

java1.6众多例子参考

/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed 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.
 */
/*
 * $Id: CachedNodeListIterator.java,v 1.2.4.1 2005/09/06 05:57:47 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;
import com.sun.org.apache.xalan.internal.xsltc.util.IntegerArray;

/**
 * CachedNodeListIterator is used for select expressions in a 
 * variable or parameter. This iterator caches all nodes in an 
 * IntegerArray. Its cloneIterator() method is overridden to 
 * return an object of ClonedNodeListIterator.
 */
public final class CachedNodeListIterator extends DTMAxisIteratorBase {

    /**
     * Source for this iterator.
     */
    private DTMAxisIterator _source;
    private IntegerArray _nodes = new IntegerArray();
    private int _numCachedNodes = 0;
    private int _index = 0;
    private boolean _isEnded = false;

    public CachedNodeListIterator(DTMAxisIterator source) {
	_source = source;
    }

    public void setRestartable(boolean isRestartable) {
	//_isRestartable = isRestartable;
	//_source.setRestartable(isRestartable);
    }

    public DTMAxisIterator setStartNode(int node) {
	if (_isRestartable) {
	    _startNode = node;
	    _source.setStartNode(node);
	    resetPosition();
	    
	    _isRestartable = false;
	}
	return this;
    }

    public int next() {
        return getNode(_index++);
    }
    
    public int getPosition() {
    	return _index == 0 ? 1 : _index;
    }
    
    public int getNodeByPosition(int pos) {
    	return getNode(pos);
    }
        
    public int getNode(int index) {
        if (index < _numCachedNodes) {
            return _nodes.at(index);
        }
        else if (!_isEnded){
            int node = _source.next();
            if (node != END) {
            	_nodes.add(node);
            	_numCachedNodes++;
            }
            else {
            	_isEnded = true;
            }
            return node;
        }
        else
            return END;
    }

    public DTMAxisIterator cloneIterator() {
	ClonedNodeListIterator clone = new ClonedNodeListIterator(this);
	return clone;
    }

    public DTMAxisIterator reset() {
    	_index = 0;
    	return this;
    }
    
    public void setMark() {
	_source.setMark();
    }

    public void gotoMark() {
	_source.gotoMark();
    }
}