| /******************************************************************************* |
| * Copyright (c) 2012, 2015 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.utility.internal.stack; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.EmptyStackException; |
| import org.eclipse.jpt.common.utility.internal.ArrayTools; |
| import org.eclipse.jpt.common.utility.stack.Stack; |
| |
| /** |
| * Resizable-array LIFO implementation of the {@link Stack} interface. |
| * @param <E> the type of elements maintained by the stack |
| * @see FixedCapacityArrayStack |
| * @see StackTools |
| */ |
| public class ArrayStack<E> |
| implements Stack<E>, Cloneable, Serializable |
| { |
| private transient E[] elements; |
| |
| private int size = 0; |
| |
| private static final long serialVersionUID = 1L; |
| |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct an empty stack. |
| */ |
| public ArrayStack() { |
| this(10); |
| } |
| |
| /** |
| * Construct an empty stack with the specified initial capacity. |
| */ |
| @SuppressWarnings("unchecked") |
| public ArrayStack(int initialCapacity) { |
| super(); |
| if (initialCapacity < 0) { |
| throw new IllegalArgumentException("Illegal capacity: " + initialCapacity); //$NON-NLS-1$ |
| } |
| this.elements = (E[]) new Object[initialCapacity]; |
| } |
| |
| |
| // ********** Stack implementation ********** |
| |
| public void push(E element) { |
| this.ensureCapacity(this.size + 1); |
| this.elements[this.size++] = element; |
| } |
| |
| /** |
| * Increase the stack's capacity, if necessary, to ensure it has at least |
| * the specified minimum capacity. |
| */ |
| public void ensureCapacity(int minCapacity) { |
| if (this.elements.length < minCapacity) { |
| int newCapacity = ((this.elements.length * 3) >> 1) + 1; |
| if (newCapacity < minCapacity) { |
| newCapacity = minCapacity; |
| } |
| this.elements = this.copyElements(newCapacity); |
| } |
| } |
| |
| /** |
| * Decrease the stack's capacity, if necessary, to match its current size. |
| */ |
| public void trimToSize() { |
| if (this.elements.length > this.size) { |
| this.elements = this.copyElements(this.size); |
| } |
| } |
| |
| private E[] copyElements(int newCapacity) { |
| @SuppressWarnings("unchecked") |
| E[] newElements = (E[]) new Object[newCapacity]; |
| if (this.size != 0) { |
| System.arraycopy(this.elements, 0, newElements, 0, this.size); |
| } |
| return newElements; |
| } |
| |
| public E pop() { |
| if (this.size == 0) { |
| throw new EmptyStackException(); |
| } |
| int index = this.size - 1; |
| E element = this.elements[index]; |
| this.elements[index] = null; // allow GC to work |
| this.size--; |
| return element; |
| } |
| |
| public E peek() { |
| if (this.size == 0) { |
| throw new EmptyStackException(); |
| } |
| return this.elements[this.size - 1]; |
| } |
| |
| public boolean isEmpty() { |
| return this.size == 0; |
| } |
| |
| |
| // ********** standard methods ********** |
| |
| @Override |
| public ArrayStack<E> clone() { |
| try { |
| @SuppressWarnings("unchecked") |
| ArrayStack<E> clone = (ArrayStack<E>) super.clone(); |
| @SuppressWarnings("cast") |
| E[] array = (E[]) this.elements.clone(); |
| clone.elements = array; |
| return clone; |
| } catch (CloneNotSupportedException ex) { |
| throw new InternalError(); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return Arrays.toString(ArrayTools.reverse(this.copyElements(this.size))); |
| } |
| |
| |
| // ********** Serializable "implementation" ********** |
| |
| private void writeObject(java.io.ObjectOutputStream stream) throws java.io.IOException { |
| // write size (and any hidden stuff) |
| stream.defaultWriteObject(); |
| Object[] array = this.elements; |
| int elementsLength = array.length; |
| stream.writeInt(elementsLength); |
| for (int i = 0; i < this.size; i++) { |
| stream.writeObject(array[i]); |
| } |
| } |
| |
| @SuppressWarnings("unchecked") |
| private void readObject(java.io.ObjectInputStream stream) throws java.io.IOException, ClassNotFoundException { |
| // read size (and any hidden stuff) |
| stream.defaultReadObject(); |
| int elementsLength = stream.readInt(); |
| Object[] array = new Object[elementsLength]; |
| for (int i = 0; i < this.size; i++) { |
| array[i] = stream.readObject(); |
| } |
| this.elements = (E[]) array; |
| } |
| } |