content: /*
   * $Id: LuaStateFactory.java,v 1.4 2006/12/22 14:06:40 thiago Exp $
   * Copyright (C) 2003-2007 Kepler Project.
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
   * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  package org.keplerproject.luajava;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * This class is responsible for instantiating new LuaStates.
   * When a new LuaState is instantiated it is put into a List
   * and an index is returned. This index is registred in Lua
   * and it is used to find the right LuaState when lua calls
   * a Java Function.
   * 
   * @author Thiago Ponte
   */
  public final class LuaStateFactory
  {
  	/**
  	 * Array with all luaState's instances
  	 */
  	private static final List states = new ArrayList();
  	
  	/**
  	 * Non-public constructor. 
  	 */
  	private LuaStateFactory()
  	{}
  	
  	/**
  	 * Method that creates a new instance of LuaState
  	 * @return LuaState
  	 */
  	public synchronized static LuaState newLuaState()
  	{
  		int i = getNextStateIndex();
  		LuaState L = new LuaState(i);
  		
  		states.add(i, L);
  		
  		return L;
  	}
  	
  	/**
  	 * Returns a existing instance of LuaState
  	 * @param index
  	 * @return LuaState
  	 */
  	public synchronized static LuaState getExistingState(int index)
  	{
  		return (LuaState) states.get(index);
  	}
  	
  	/**
  	 * Receives a existing LuaState and checks if it exists in the states list.
  	 * If it doesn't exist adds it to the list.
  	 * @param L
  	 * @return int
  	 */
  	public synchronized static int insertLuaState(LuaState L)
  	{
  		int i;
  		for (i = 0 ; i < states.size() ; i++)
  		{
  			LuaState state = (LuaState) states.get(i);
  			
  			if (state != null)
  			{
  				if (state.getCPtrPeer() == L.getCPtrPeer())
  					return i;
  			}
  		}
  
  		i = getNextStateIndex();
  		
  		states.set(i, L);
  		
  		return i;
  	}
  	
  	/**
  	 * removes the luaState from the states list
  	 * @param idx
  	 */
  	public synchronized static void removeLuaState(int idx)
  	{
  		states.add(idx, null);
  	}
  	
  	/**
  	 * Get next available index
  	 * @return int
  	 */
  	private synchronized static int getNextStateIndex()
  	{
  		int i;
  		for ( i=0 ; i < states.size() && states.get(i) != null ; i++ );
  		
  		return i;
  	}
  }