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., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 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 
ConnectionRunner(ThreadGroup group, String id)54       public ConnectionRunner(ThreadGroup group, String id){
55         super(group, id);
56       }
57 
run()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 
dispatch(UnicastConnection conn)78       public synchronized void dispatch(UnicastConnection conn){
79         this.conn = conn;
80         notify();
81       }
82 
exit()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, Integer.toString(i));
107       pools[i].setContextClassLoader(Thread.currentThread().getContextClassLoader());
start()108       pools[i].start();
109     }
110     freelist = new ArrayList(Arrays.asList(pools));
111   }
112 
setSize(int size_)113   public static void setSize(int size_){
114     size = size_;
115   }
116 
setMaxSize(int size)117   public static void setMaxSize(int size){
118     max_size = size;
119   }
120 
getConnectionRunner()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, Integer.toString(size));
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 
dispatchConnection(UnicastConnection conn)142   public static void dispatchConnection(UnicastConnection conn)
143   {
144     ConnectionRunner r = getConnectionRunner();
145     r.dispatch(conn);
146   }
147 
exit()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 }
157