/*
* 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.commons.jxpath;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* A simple implementation of {@link NodeSet} that behaves as a collection
* of pointers.
*
* @author Dmitri Plotnikov
* @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
*/
public class BasicNodeSet implements NodeSet {
private List pointers = new ArrayList();
private List readOnlyPointers;
private List nodes;
private List values;
/**
* Add a pointer to this NodeSet.
* @param pointer to add
*/
public void add(Pointer pointer) {
if (pointers.add(pointer)) {
clearCacheLists();
}
}
/**
* Add the specified NodeSet to this NodeSet.
* @param nodeSet to add
*/
public void add(NodeSet nodeSet) {
if (pointers.addAll(nodeSet.getPointers())) {
clearCacheLists();
}
}
/**
* Remove a pointer from this NodeSet.
* @param pointer to remove
*/
public void remove(Pointer pointer) {
if (pointers.remove(pointer)) {
clearCacheLists();
}
}
public synchronized List getPointers() {
if (readOnlyPointers == null) {
readOnlyPointers = Collections.unmodifiableList(pointers);
}
return readOnlyPointers;
}
public synchronized List getNodes() {
if (nodes == null) {
nodes = new ArrayList();
for (int i = 0; i < pointers.size(); i++) {
Pointer pointer = (Pointer) pointers.get(i);
nodes.add(pointer.getNode());
}
nodes = Collections.unmodifiableList(nodes);
}
return nodes;
}
public synchronized List getValues() {
if (values == null) {
values = new ArrayList();
for (int i = 0; i < pointers.size(); i++) {
Pointer pointer = (Pointer) pointers.get(i);
values.add(pointer.getValue());
}
values = Collections.unmodifiableList(values);
}
return values;
}
public String toString() {
return pointers.toString();
}
/**
* Clear cache list members.
*/
private synchronized void clearCacheLists() {
readOnlyPointers = null;
nodes = null;
values = null;
}
}
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