Threaded Java - Java - page 866

But what if your thread is blocked reading from a network connection? You then cannot
check a Boolean, because the thread that is reading is asleep. This is what the stop method
was designed for, but, as we've seen, it is now deprecated. Instead, you can simply close the
socket. The program shown in Example 22-8 intentionally deadlocks itself by reading from a
socket that you are supposed to write to, simply to demonstrate that closing the socket does
in fact terminate the loop.

Example 22-8. StopClose.java
public public class class StopClose StopClose extends extends Thread {

protected protected Socket io ;

public public void void run () {

try try {

io = new new Socket ( "java.sun.com" , 80 ); // HTTP

BufferedReader is = new new BufferedReader (

new InputStreamReader ( io . getInputStream ()));
System . out . println ( "StopClose reading" );

new

// The following line will deadlock (intentionally), since HTTP
// enjoins the client to send a request (like "GET / HTTP/1.0")
// and a null line, before reading the response.

String line = is . readLine (); // DEADLOCK

// Should only get out of the readLine if an interrupt
// is thrown, as a result of closing the socket.

// So we shouldn't get here, ever:
System . out . printf ( "StopClose FINISHED after reading %s!?" , line );
} catch catch ( IOException ex ) {

System . out . println ( "StopClose terminating: " + ex );

}

}

public public void void shutDown () throws throws IOException {

iif ( io != null null ) {

// This is supposed to interrupt the waiting read.
synchronized synchronized ( io ) {

io . close ();

}

}
System . out . println ( "StopClose.shutDown() completed" );

}