content: /**
   * ﻿Copyright (C) 2007 - 2019 52°North Initiative for Geospatial Open Source
   * Software GmbH
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   *
   * If the program is linked with libraries which are licensed under one of
   * the following licenses, the combination of the program with the linked
   * library is not considered a "derivative work" of the program:
   *
   *       • Apache License, version 2.0
   *       • Apache Software License, version 1.0
   *       • GNU Lesser General Public License, version 3
   *       • Mozilla Public License, versions 1.0, 1.1 and 2.0
   *       • Common Development and Distribution License (CDDL), version 1.0
   *
   * Therefore the distribution of the program linked with libraries licensed
   * under the aforementioned licenses, is permitted by the copyright holders
   * if the distribution is compliant with both the GNU General Public
   * License version 2 and the aforementioned licenses.
   *
   * This program 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 General
   * Public License for more details.
   */
  package org.n52.wps.server;
  
  import java.util.ArrayList;
  
  
  /**
   * @author Matthias Mueller, TU Dresden
   *
   */
  public class ProcessIDRegistry {
  	
  	private static ProcessIDRegistry instance = new ProcessIDRegistry();
  	private volatile boolean lock = false;
  	private static ArrayList<String> idList = new ArrayList<String>();
  	
  	private ProcessIDRegistry(){
  		//empty private constructor
  	}
  	
  	public static ProcessIDRegistry getInstance(){
  		return instance;
  	}
  	
  	public boolean addID(String id){
  		while (lock){
  			//spin
  		}
  		try{
  			lock = true;
  			boolean retval = idList.add(id);
  			lock = false;
  			return retval;
  		}
  		finally{
  			lock = false;
  		}
  	}
  	
  	public synchronized boolean removeID(String id){
  		while (lock){
  			//spin
  		}
  		try{
  			lock = true;
  			boolean retval = idList.remove(id);
  			lock = false;
  			return retval;
  		}
  		finally{
  			lock = false;
  		}
  	}
  	
  	public boolean containsID(String id){
  		return idList.contains(id);
  	}
  	
  	public String[] getIDs(){
  		return idList.toArray(new String[idList.size()]);
  	}
  	
  	protected void clearRegistry(){
  		while (lock){
  			//spin
  		}
  		try{
  			lock = true;
  			idList.clear();
  			lock = false;
  		}
  		finally{
  			lock = false;
  		}
  	}
  }
  