| /* |
| * 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 $Revision$ $Date$ |
| */ |
| 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; |
| } |
| |
| } |