com.google.gwt.dev.util.collect.Stack Maven / Gradle / Ivy
/*
* 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 the value type
*/
public final class Stack implements Iterable {
private ArrayList 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 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 pop(int count) {
int size = elements.size();
List nodesToPop = elements.subList(size - count, size);
List 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 Stack create() {
return new Stack();
}
}