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Java > Open Source Codes > com > go > trove > net > SocketConnector


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52
53 package com.go.trove.net;
54
55 import java.io.*;
56 import java.net.*;
57 import java.util.*;
58 import com.go.trove.util.*;
59
60 /******************************************************************************
61  * Allows client socket connections to be established with a timeout.
62  *
63  * @author Brian S O'Neill
64  * @version
65  * <!--$$Revision:--> 2 <!-- $-->, <!--$$JustDate:--> 00/12/05 <!-- $-->
66  */

67 public class SocketConnector {
68     // Limit the number of threads that may simultaneously connect to a
69
// specific destination.
70
private static final int CONNECT_THREAD_MAX = 5;
71
72     // Maps address:port pairs to ThreadPools for connecting.
73
private static Map mConnectors =
74         Collections.synchronizedMap(new SoftHashMap());
75
76     /**
77      * @param timeout Max time to wait for new connection. If negative, wait
78      * is infinite.
79      * @return null if couldn't connect in time.
80      */

81     public static Socket connect(String JavaDoc host, int port, long timeout)
82         throws SocketException
83     {
84         return connect((Object JavaDoc)host, port, timeout);
85     }
86
87
88     /**
89      * @param timeout Max time to wait for new connection. If negative, wait
90      * is infinite.
91      * @return null if couldn't connect in time.
92      */

93     public static Socket connect(InetAddress address, int port, long timeout)
94         throws SocketException
95     {
96         return connect((Object JavaDoc)address, port, timeout);
97     }
98
99     /**
100      * @param address either a string or InetAddress.
101      * @param timeout Max time to wait for new connection. If negative, wait
102      * is infinite.
103      * @return null if couldn't connect in time
104      */

105     private static Socket connect(Object JavaDoc address, int port, long timeout)
106         throws SocketException
107     {
108         Key key = new Key(address, port);
109         ThreadPool pool;
110         synchronized (mConnectors) {
111             pool = (ThreadPool)mConnectors.get(key);
112             if (pool == null) {
113                 pool = new ThreadPool
114                     ("SocketConnector[" + key + ']', CONNECT_THREAD_MAX);
115                 pool.setIdleTimeout(10000);
116                 mConnectors.put(key, pool);
117             }
118         }
119
120         Connector connector = new Connector(key);
121         Thread JavaDoc thread;
122
123         long start;
124         if (timeout > 0) {
125             start = System.currentTimeMillis();
126         }
127         else {
128             start = 0;
129         }
130
131         try {
132             thread = pool.start(connector, timeout);
133         }
134         catch (InterruptedException JavaDoc e) {
135             return null;
136         }
137
138         if (timeout > 0) {
139             timeout = timeout - (System.currentTimeMillis() - start);
140             if (timeout < 0) {
141                 timeout = 0;
142             }
143         }
144
145         try {
146             Socket socket = connector.connect(timeout);
147             if (socket != null) {
148                 return socket;
149             }
150         }
151         catch (InterruptedException JavaDoc e) {
152         }
153
154         thread.interrupt();
155         return null;
156     }
157
158     private SocketConnector() {
159     }
160
161     private static class Key {
162         final Object JavaDoc mAddress;
163         final int mPort;
164
165         Key(Object JavaDoc address, int port) {
166             mAddress = address;
167             mPort = port;
168         }
169
170         public boolean equals(Object JavaDoc obj) {
171             if (obj instanceof Key) {
172                 Key key = (Key)obj;
173                 return key.mAddress.equals(mAddress) && key.mPort == mPort;
174             }
175             return false;
176         }
177
178         public int hashCode() {
179             return mAddress.hashCode() + mPort;
180         }
181
182         public String JavaDoc toString() {
183             if (mAddress instanceof InetAddress) {
184                 return ((InetAddress)mAddress).getHostAddress() + ':' + mPort;
185             }
186             else {
187                 return String.valueOf(mAddress) + ':' + mPort;
188             }
189         }
190     }
191
192     private static class Connector implements Runnable JavaDoc {
193         private final Key mKey;
194         private Object JavaDoc mSocketOrException;
195         private boolean mDoneWaiting;
196
197         public Connector(Key key) {
198             mKey = key;
199         }
200
201         public synchronized Socket connect(long timeout)
202             throws SocketException, InterruptedException JavaDoc
203         {
204             try {
205                 if (mSocketOrException == null) {
206                     if (timeout < 0) {
207                         wait();
208                     }
209                     else if (timeout > 0) {
210                         wait(timeout);
211                     }
212                     else {
213                         return null;
214                     }
215                 }
216             }
217             finally {
218                 mDoneWaiting = true;
219             }
220
221             if (mSocketOrException instanceof Socket) {
222                 return (Socket)mSocketOrException;
223             }
224             else if (mSocketOrException instanceof InterruptedIOException) {
225                 throw new InterruptedException JavaDoc();
226             }
227             else if (mSocketOrException instanceof Exception JavaDoc) {
228                 throw new SocketException
229                     ("Unable to connect to " + mKey + ", " +
230                      ((Exception JavaDoc)mSocketOrException).getMessage());
231             }
232
233             return null;
234         }
235
236         public void run() {
237             try {
238                 Socket socket;
239                 Object JavaDoc address = mKey.mAddress;
240                 if (address instanceof InetAddress) {
241                     socket = new Socket((InetAddress)address, mKey.mPort);
242                 }
243                 else {
244                     socket = new Socket(String.valueOf(address), mKey.mPort);
245                 }
246
247                 synchronized (this) {
248                     if (mDoneWaiting) {
249                         try {
250                             socket.close();
251                         }
252                         catch (IOException e) {
253                         }
254                     }
255                     else {
256                         mSocketOrException = socket;
257                         notify();
258                     }
259                 }
260             }
261             catch (Exception JavaDoc e) {
262                 synchronized (this) {
263                     mSocketOrException = e;
264                     notify();
265                 }
266             }
267         }
268     }
269 }
270
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