property.java

发布/订阅系统路由重配算法,可应用于ad hoc环境

/*
 * project: RebecaSim
 * package: graph
 * file:    Property.java
 * 
 * version: 0.1
 * date:    02.04.2005
 * 
 * This software is part of the diploma thesis "Ein adaptives Brokernetz 
 * für Publish/Subscribe Systeme".
 */
package graph;

import util.*;

/**
 * TODO Insert class description here.
 *
 * @version 02.04.2005
 * @author  parzy
 */
public class Property {

	private static long tmpId = 0;
	
	private final String key;
	
	private final boolean isTemporary;
	
	private SimpleHashtable elements;
	
	private boolean manageElements;
	
	private synchronized static long getTmpId() {
		return tmpId++;
	}
	
	public Property() {
		this.key = "tmp." + Property.getTmpId();
		this.isTemporary = true;
		this.elements = new SimpleHashtable();
		this.manageElements = true;
	}
	
	public Property(String name) {
		this.key = "prop." + name;
		this.isTemporary = false;
		this.elements = null;
		this.manageElements = false;
	}
	
	public boolean equals(Object o) {
		return (o instanceof Property) && this.key.equals(((Property)o).key);
	}

	public int hashCode() {
		return key.hashCode();
	}
	
	public String toString() {
		return key;
	}
	
	String getKey() {
		return key;
	}
	
	synchronized void addElement(Element e) {
		
		if (manageElements) {
			if (e == null) {
				throw new NullPointerException("Null is not a valid element.");
			}
			//System.out.println("Put element "+e);
			elements.put(e,e);
		}
	}
	
	synchronized void removeElement(Element e) {

		if (manageElements) {
			if (e == null) {
				throw new NullPointerException("Null is not a valid element.");
			}
			elements.remove(e);
		}
	}
	
	public synchronized void clear() {
		if (isTemporary) {
			manageElements = false;
			elements.keyIterator.reset();
			while (elements.keyIterator.hasNext()) {
				((Element)elements.keyIterator.next()).removeProperty(this);
			}
			elements.clear();
			manageElements = true;
		}
	}
	
	protected void finalize() throws Throwable {
		if (isTemporary) {
			manageElements = false;
			elements.keyIterator.reset();
			while (elements.keyIterator.hasNext()) {
				((Element)elements.keyIterator.next()).removeProperty(this);
			}
		}
		elements = null;
		super.finalize();
	}
	
	public synchronized ResetableIterator getElements(){
		return elements == null ? null : elements.keyIterator();
	}
	
	public int size() {
		return elements.size();
	}
}