org.piccolo2d.util.PStack Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2019, Piccolo2D project, http://piccolo2d.org
* Copyright (c) 1998-2008, University of Maryland
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided
* that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list of conditions
* and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this list of conditions
* and the following disclaimer in the documentation and/or other materials provided with the
* distribution.
*
* None of the name of the University of Maryland, the name of the Piccolo2D project, or the names of its
* contributors may be used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.piccolo2d.util;
import java.util.ArrayList;
/**
* PStack this class should be removed when a non thread safe stack is
* added to the java class libraries.
*
*
* @version 1.0
* @author Jesse Grosjean
*/
public class PStack extends ArrayList {
/**
* Allows for future serialization code to understand versioned binary
* formats.
*/
private static final long serialVersionUID = 1L;
/**
* Creates an empty stack.
*/
public PStack() {
}
/**
* Pushes the provided object onto the top of the stack.
*
* @param o object to add to the stack
*/
public void push(final Object o) {
add(o);
}
/**
* Returns topmost element on the stack, or null if stack is empty.
*
* @return topmost element on the stack, or null if empty
*/
public Object peek() {
final int s = size();
if (s == 0) {
return null;
}
else {
return get(s - 1);
}
}
/**
* Removes top element on the stack and returns it.
*
* @return topmost element on stack.
*/
public Object pop() {
return remove(size() - 1);
}
}