Re: need to send exceptions to anthor method

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 28 Dec 2007 22:04:05 -0500
Message-ID:
<oJGdnYtCzeG4JOjanZ2dnUVZ_hKdnZ2d@comcast.com>
islamelnaggar@gmail.com wrote:

Hello java guys
i'm writing multi-thread server so i need help with this topic

the point is i'm calling method to read socket input i need my called
class thread to be stopped
if the reader method catch an exception
thanks

class testclass{
    public testclass(){
        //some code to read data from socket
       try{
       socket.read();
      }
      catch(IOException e){
       //Dosomething
      }
    }

}

public class main{
   public static void main(){
       testclass = new testclass();
       // i need this class to stop if called class catch an
exception ...

  }
}


As written, your code will stop after one socket read anyway, assuming
'socket' is of a type that has a read() method.

Even if you put the read() in a loop, inside the try {} block, the loop will
break on the exception and will end. No special action needed on your part.

You also do not need to rethrow the exception.

You absolutely DO need to move the read() out of the constructor for the
class. You also should name the class with an initial upper-case letter. You
should consider making the class public. The name should reflect the purpose
of a class, not that it is a class. Of course it's a class. Every class is a
class.

If your main() method lacks a String [] parameter and is not static, you
cannot run it from the command line.

public class TestSocket
{
  private static final int BUFZ = 8192;

  public byte [] readSocket( String host, int port )
  {
    Socket socket;
    try
    {
      socket = new Socket( host, port );
    }
    catch ( Exception e )
    {
      throw new IllegalStateException( e );
    }

    try
    {
      return readSocket( socket );
    }
    finally
    {
      try
      {
        socket.close();
      }
      catch ( IOException e )
      {
        System.err.println( "Socket close. "+e.getMessage();
      }
    }
  }

  public byte [] readSocket( Socket socket )
  {
    ByteArrayOutputStream baos = new ByteArrayOutputStream( BUFZ );
    try
    {
      InputStream ins = socket.getInputStream();

      byte buf [] = new byte [BUFZ];
      for( int bred; (bred = ins.read( buf )) > -1; )
      {
        baos.write( buf, 0, bred );
      }
      return baos.toByteArray();
    }
    catch( IOException e )
    {
      throw new IllegalStateException( e );
    }
    finally
    {
      try { baos.close(); } catch ( IOException e ) {}
    }
  }

  public static void main( String [] args )
  {
    TestSocket tester = new TestSocket();
    try
    {
      byte [] got = tester.readSocket( "localhost", 6666 );
      System.out.println( got );
    }
    catch ( IllegalStateException e )
    {
      System.err.println( "TestSocket.readSocket(): " + e.getMessage() );
    }
  }
}

--
Lew

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