utils/eclipselink.utils.workbench/utility/source/org/eclipse/persistence/tools/workbench/utility/SimpleStack.java

/*******************************************************************************
 * Copyright (c) 1998, 2013 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the 
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 
 * which accompanies this distribution. 
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility;

import java.io.Serializable;
import java.util.EmptyStackException;
import java.util.LinkedList;
import java.util.NoSuchElementException;

/**
 * Straightforward implementation of the Stack interface.
 */
public class SimpleStack
	implements Stack, Cloneable, Serializable
{
	private LinkedList elements;

	private static final long serialVersionUID = 1L;


	// ********** constructors **********

	/**
	 * Construct an empty stack.
	 */
	public SimpleStack() {
		super();
		this.elements = new LinkedList();
	}


	// ********** Stack implementation **********

	/**
	 * @see Stack#push(Object)
	 */
	public void push(Object o) {
		this.elements.addLast(o);
	}

	/**
	 * @see Stack#pop()
	 */
	public Object pop() {
		try {
			return this.elements.removeLast();
		} catch (NoSuchElementException ex) {
			throw new EmptyStackException();
		}
	}

	/**
	 * @see Stack#peek()
	 */
	public Object peek() {
		try {
			return this.elements.getLast();
		} catch (NoSuchElementException ex) {
			throw new EmptyStackException();
		}
	}

	/**
	 * @see Stack#isEmpty()
	 */
	public boolean isEmpty() {
		return this.elements.isEmpty();
	}


	// ********** Cloneable implementation **********

	/**
	 * @see Object#clone()
	 */
	public Object clone() {
		SimpleStack clone;
		try {
			clone = (SimpleStack) super.clone();
		} catch (CloneNotSupportedException ex) {
			throw new InternalError();
		}
		clone.elements = (LinkedList) this.elements.clone();
		return clone;
	}

}