| /* |
| * 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.tools.ant.util; |
| |
| import java.util.Stack; |
| |
| /** |
| * Identity Stack. |
| * @since Ant 1.7 |
| */ |
| public class IdentityStack extends Stack { |
| |
| private static final long serialVersionUID = -5555522620060077046L; |
| |
| /** |
| * Get an IdentityStack containing the contents of the specified Stack. |
| * @param s the Stack to copy; ignored if null. |
| * @return an IdentityStack instance. |
| */ |
| public static IdentityStack getInstance(Stack s) { |
| if (s instanceof IdentityStack) { |
| return (IdentityStack) s; |
| } |
| IdentityStack result = new IdentityStack(); |
| if (s != null) { |
| result.addAll(s); |
| } |
| return result; |
| } |
| |
| /** |
| * Default constructor. |
| */ |
| public IdentityStack() { |
| } |
| |
| /** |
| * Construct a new IdentityStack with the specified Object |
| * as the bottom element. |
| * @param o the bottom element. |
| */ |
| public IdentityStack(Object o) { |
| super(); |
| push(o); |
| } |
| |
| /** |
| * Override methods that use <code>.equals()</code> comparisons on elements. |
| * @param o the Object to search for. |
| * @return true if the stack contains the object. |
| * @see java.util.Vector#contains(Object) |
| */ |
| public synchronized boolean contains(Object o) { |
| return indexOf(o) >= 0; |
| } |
| |
| /** |
| * Override methods that use <code>.equals()</code> comparisons on elements. |
| * @param o the Object to search for. |
| * @param pos the position from which to search. |
| * @return the position of the object, -1 if not found. |
| * @see java.util.Vector#indexOf(Object, int) |
| */ |
| public synchronized int indexOf(Object o, int pos) { |
| for (int i = pos; i < size(); i++) { |
| if (get(i) == o) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| /** |
| * Override methods that use <code>.equals()</code> comparisons on elements. |
| * @param o the Object to search for. |
| * @param pos the position from which to search (backward). |
| * @return the position of the object, -1 if not found. |
| * @see java.util.Vector#indexOf(Object, int) |
| */ |
| public synchronized int lastIndexOf(Object o, int pos) { |
| for (int i = pos; i >= 0; i--) { |
| if (get(i) == o) { |
| return i; |
| } |
| } |
| return -1; |
| } |
| |
| } |