package ca.ubc.cs.spl.aspectPatterns.examples.state.java;
/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This file is part of the design patterns project at UBC
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is ca.ubc.cs.spl.aspectPatterns.
*
* For more details and the latest version of this code, please see:
* http://www.cs.ubc.ca/labs/spl/projects/aodps.html
*
* Contributor(s):
*/
/**
* Implements the <i>context</i> of the queue example. This is effectively
* a queue with limited capacity. Requests are forwarded to the current state
* object.
*
* @author Jan Hannemann
* @author Gregor Kiczales
* @version 1.1, 02/17/04
*/
public class Queue implements QueueContext {
/**
* the current <i>State</i> of this <i>Context</i>
*/
protected QueueState state = new QueueEmpty();
/**
* Tries to insert an object into the queue. Returns true if successful,
* false otherwiese.
*
* @param arg the object to be inserted into the queue
* @return true if insertion was successful, false otherwise.
*/
public boolean insert(Object arg) {
return state.insert(this, arg);
}
/**
* Returns the first item in the queue
*
* @return the first item in the queue
*/
public Object getFirst() {
return state.getFirst(this);
}
/**
* Tries to remove an object from the queue. Returns true if successful,
* false otherwise.
*
* @return true if deletion was successful, false otherwise.
*/
public boolean removeFirst() { // Removes the first element from the queue
return state.removeFirst(this);
}
/**
* Sets the state of the context to the arguments state.
*
* @param state the new state for the context object.
*/
public void setState(QueueState state) {
this.state = state;
}
}