requestqueue.java

JAVA平台下优秀的CHART开源代码,可以实现类似EXCEL中的二维或三维的饼图/椎图功能.

/**
 * Copyright (C) 2003  Manfred Andres
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * 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.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package freecs.core;
import freecs.util.ObjectBuffer;
import freecs.Server;
import java.nio.channels.SelectionKey;

public class RequestQueue {
   private long 	lastCheck;
   private float  lastPerc = 0;
   private RequestReader req;

   private ObjectBuffer requests;

   public RequestQueue (RequestReader r) {
      requests = new ObjectBuffer (Server.srv.READER_MAX_QUEUE);
      req=r;
   }

   public double getUsage () {
      double onePerc = ((double) requests.capacity ()) / ((double) 100);
      return ((double) requests.size()) / onePerc;
   }

   public boolean addKey (SelectionKey sk) {
		if (!sk.isValid () || !sk.channel ().isOpen ()) 
			return true;
		int i = 0;
		synchronized (requests) {
			boolean result = requests.put (sk);
			while (!result) {
				if (i > 5) {
					Server.log ("RequestQueue.addKey: Tried 5 times to add key.", Server.MSG_STATE, Server.LVL_MAJOR);
					return false;
				}
				try {
					requests.wait (30);
				} catch (InterruptedException ie) { }
				result = requests.put (sk);
				i++;
			}
			requests.notify();
		}
		return true;
	}
   
	public int size () {
		return requests.size();
	}

   public SelectionKey getKey (long timeout) {
      long returnTime = System.currentTimeMillis () + timeout;
      SelectionKey sk;
      synchronized (requests) {
		  sk = (SelectionKey) requests.get ();
	      while (sk == null && System.currentTimeMillis () < returnTime) {
			 try {
			    requests.wait (100);
			 } catch (InterruptedException ie) { }
	         sk = (SelectionKey) requests.get ();
	      }
      }
      return sk;
   }
   
   public SelectionKey popKey () {
   		synchronized (requests) {
   			SelectionKey rk = (SelectionKey) requests.pop();
   			requests.notify();
			return rk;
   		}
   }
}