libjava/gnu/java/rmi/server/ConnectionRunnerPool.java

   1 /* gnu.java.rmi.server.ConnectionRunnerPool
   2    Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package gnu.java.rmi.server;
  40
  41 import java.util.ArrayList;
  42 import java.util.Arrays;
  43
  44 //Should I generalize this class?
  45
  46 class ConnectionRunnerPool
  47 {
  48
  49   public static
  50     class ConnectionRunner extends Thread{
  51       private UnicastConnection conn;
  52       private volatile boolean exiting = false;
  53
  54       public ConnectionRunner(ThreadGroup group, String id){
  55         super(group, id);
  56       }
  57
  58       public synchronized void run(){
  59         while(!exiting){
  60           if(conn == null)
  61             try{
  62               wait();
  63             }catch(InterruptedException e){
  64               continue;
  65             }
  66           else{
  67             conn.run();
  68             conn = null;
  69             synchronized(ConnectionRunnerPool.class){
  70               freelist.add(this);
  71               if(freelist.size() == 1)
  72                 ConnectionRunnerPool.class.notifyAll();
  73             }
  74           }
  75         }
  76       }
  77
  78       public synchronized void dispatch(UnicastConnection conn){
  79         this.conn = conn;
  80         notify();
  81       }
  82
  83       void exit(){
  84         exiting = true;
  85         if(conn != null)
  86           try{
  87             join(500);
  88           }catch(InterruptedException e){}
  89         interrupt();
  90       }
  91
  92     }
  93
  94   // Should this value equal to number of CPU?
  95   private static int size = 5;
  96   private static int max_size = 10;
  97
  98   // Package-private to avoid a trampoline.
  99   static ArrayList freelist;
 100
 101   private static ThreadGroup group = new ThreadGroup("pool");
 102
 103   static {
 104     ConnectionRunner[] pools = new ConnectionRunner[size];
 105     for(int i = 0; i < pools.length; i++){
 106       pools[i] = new ConnectionRunner(group, new Integer(i).toString());
 107       pools[i].setContextClassLoader(Thread.currentThread().getContextClassLoader());
 108       pools[i].start();
 109     }
 110     freelist = new ArrayList(Arrays.asList(pools));
 111   }
 112
 113   public static void setSize(int size_){
 114     size = size_;
 115   }
 116
 117   public static void setMaxSize(int size){
 118     max_size = size;
 119   }
 120
 121   private static synchronized ConnectionRunner getConnectionRunner()
 122   {
 123     if(freelist.size() == 0){
 124       if(size < max_size){
 125         ++size;
 126         ConnectionRunner a = new ConnectionRunner(group, new Integer(size).toString());
 127         a.start();
 128         freelist.add(a);
 129       }else
 130         while(freelist.size() == 0)
 131           try{
 132             ConnectionRunnerPool.class.wait();
 133           }catch(InterruptedException e){}
 134     }
 135
 136     // always let the first in pool most busy or other scheduling plan??
 137     ConnectionRunner a = (ConnectionRunner)freelist.get(0);
 138     freelist.remove(a);
 139     return a;
 140   }
 141
 142   public static void dispatchConnection(UnicastConnection conn)
 143   {
 144     ConnectionRunner r = getConnectionRunner();
 145     r.dispatch(conn);
 146   }
 147
 148   public static void exit()
 149   {
 150     Thread[] list = new Thread[group.activeCount()];
 151     group.enumerate(list);
 152     for(int i = 0; i < list.length; i++)
 153       ((ConnectionRunner)list[i]).exit();
 154   }
 155
 156 }