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/**
* Copyright (C) 2009 Authors
*
* This file is part of Ebean.
*
* Ebean is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* Ebean is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Ebean; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.avaje.ebeaninternal.server.util;
import java.util.ArrayList;
import java.util.EmptyStackException;
/**
* Stack based on ArrayList.
*
* @author rbygrave
*/
public class ArrayStack {
private final ArrayList list;
/**
* Creates an empty Stack with an initial size.
*/
public ArrayStack(int size) {
this.list = new ArrayList(size);
}
/**
* Creates an empty Stack.
*/
public ArrayStack() {
this.list = new ArrayList();
}
/**
* Pushes an item onto the top of this stack.
*/
public E push(E item) {
list.add(item);
return item;
}
/**
* Removes the object at the top of this stack and returns that object as
* the value of this function.
*/
public E pop() {
int len = list.size();
E obj = peek();
list.remove(len - 1);
return obj;
}
protected E peekZero(boolean retNull) {
int len = list.size();
if (len == 0) {
if (retNull) {
return null;
}
throw new EmptyStackException();
}
return list.get(len - 1);
}
/**
* Returns the object at the top of this stack without removing it.
*/
public E peek() {
return peekZero(false);
}
/**
* Returns the object at the top of this stack without removing it.
* If the stack is empty this returns null.
*/
public E peekWithNull() {
return peekZero(true);
}
/**
* Tests if this stack is empty.
*/
public boolean isEmpty() {
return list.isEmpty();
}
public int size(){
return list.size();
}
public boolean contains(Object o){
return list.contains(o);
}
}