| /* |
| * Copyright 2014 Google Inc. |
| * |
| * 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. |
| */ |
| package com.google.gwt.dev.util.collect; |
| |
| import com.google.gwt.thirdparty.guava.common.collect.Lists; |
| |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| |
| /** |
| * A Stack based on {@link ArrayList}. Unlike {@link java.util.ArrayDeque}, |
| * this one allows {@code null} values. |
| * |
| * @param <T> the value type |
| */ |
| public final class Stack<T> implements Iterable<T> { |
| |
| private ArrayList<T> elements = Lists.newArrayList(); |
| |
| /** |
| * Returns the number of elements in the stack (including pushed nulls). |
| */ |
| public int size() { |
| return elements.size(); |
| } |
| |
| /** |
| * Returns true if the stack contains element, false otherwise. |
| */ |
| public boolean contains(T element) { |
| return elements.contains(element); |
| } |
| |
| /** |
| * Returns true if the stack is empty false otherwise. |
| */ |
| public boolean isEmpty() { |
| return elements.isEmpty(); |
| } |
| |
| @Override |
| public Iterator<T> iterator() { |
| return elements.iterator(); |
| } |
| |
| /** |
| * Returns the top of the stack. |
| */ |
| public T peek() { |
| return elements.get(elements.size() - 1); |
| } |
| |
| /** |
| * Returns the element at location index (from bottom of stack). |
| */ |
| public T peekAt(int index) { |
| return elements.get(index); |
| } |
| |
| /** |
| * Returns the top of the stack and removes it. |
| * @return |
| */ |
| public T pop() { |
| return elements.remove(elements.size() - 1); |
| } |
| |
| /** |
| * Pops {@code count} elements from the stack and returns them as a list with to top of the stack |
| * last. |
| */ |
| public List<T> pop(int count) { |
| int size = elements.size(); |
| List<T> nodesToPop = elements.subList(size - count, size); |
| List<T> result = Lists.newArrayList(nodesToPop); |
| nodesToPop.clear(); |
| return result; |
| } |
| |
| public void push(T value) { |
| elements.add(value); |
| } |
| |
| /** |
| * Creates a new Stack for type {@code T}. |
| */ |
| public static <T> Stack<T> create() { |
| return new Stack<T>(); |
| } |
| } |