Open Flash Server(OFS) Code

/**
 * <strong>Selector缓存(线程相关)</strong>
 * <p>
 * 1. 减少线程切换时间
 * 2. 如果在线程的每次run调用时初始化Selector, 会增加生成对象的开销
 *
 * </p>
 *
 * @author: 汉娱网络.技术部.yangxf
 * @date: 2007-12-27
 * @version: 1.1
 **/

package com.handjoys.socket;

import java.io.IOException;
import java.nio.channels.Selector;
import java.util.EmptyStackException;
import java.util.Stack;

public class SelectorFactory{

	protected static long timeout = 5000;


	protected static int maxSelectors = 20;


	/**
	* Cache of <code>Selector</code>
	*/
	private final static Stack<Selector> selectors = new Stack<Selector>();


	/**
	* Creates the <code>Selector</code>
	*/
	static {
	 try{
	     for (int i = 0; i < maxSelectors; i++)
	         selectors.add(Selector.open());
	 } catch (IOException ex){
	     ; // do nothing.
	 }
	}


	 /**
	  * Get a exclusive <code>Selector</code>
	  */
	 public final static Selector getSelector() {
	     synchronized(selectors) {
	         Selector s = null;
	         try {
	             if ( selectors.size() != 0 )
	                 s = selectors.pop();
	         } catch (EmptyStackException ex){}

	         int attempts = 0;
	         try{
	             while (s == null && attempts < 2) {
	                 selectors.wait(timeout);
	               try {
	                     if ( selectors.size() != 0 )
	                         s = selectors.pop();
	              } catch (EmptyStackException ex){
	                     break;
	                 }
	                attempts++;
	             }
	         } catch (InterruptedException ex){};
	          return s;
	     }
	 }


	/**
	* Return the <code>Selector</code> to the cache
	*/
	public final static void returnSelector(Selector s) {
	  synchronized(selectors) {
	      selectors.push(s);
	      if (selectors.size() == 1)
	          selectors.notify();
	  }
	}

}