/*

* Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package com.nokia.helium.internaldata.ant.listener;

import java.util.Stack;

/**

 * Object to keep the elements in a stack, it supports both pop and peek (return element is kept in the stack).

 * 

 * @param <E> The type applied to the stack.

 */

public class EndLessStack<E> extends Stack<E> {

    public static final long serialVersionUID = -1L;

    private E defaultElement;

    /**

     * Create a stack with a defaultElement as the default element.

     * @param defaultElement The default element to use.

     */

    public EndLessStack(E defaultElement) {

        super();

        this.defaultElement = defaultElement;

    }

    /**

     * Create a stack with a null default element.

     */

    public EndLessStack() {

        super();

        this.defaultElement = null;

    }

    /**

     * This return the top most element out from the stack.

     * If the stack is empty it returns the defaultElement.

     * @return element 

     */

    public E pop() {

        E element = super.pop();

            return element;

        return defaultElement;

    }

    /** 

     * Endless stack is never empty. 

     */

    public boolean empty() {

        return false;

    }

    /**

     * This return the top most element from the stack.

     * If the stack is empty it returns the defaultElement.

     * The return element is kept in the stack.

     * @return element 

     */

    public E peek() {

        if (!super.empty()) {

            E element = super.peek();

            return element;

        }

        return defaultElement;

    }

    /**

     * Get default element.

     * This is the object which will get returned if the internal stack gets empty.

     * @return element 

     */

    public Object getDefaultElement() {

        return defaultElement;

    }

    /**

     * Set default element.

     * @return element 

     */

    public void setDefaultElement(E defaultElement) {

        this.defaultElement = defaultElement;

    }

}