Help in Multi threading!

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Sundar - 10 Nov 2006 13:42 GMT

Hi,

Iam working on creating an audio player applet.

I face some difficulties in multithreading in java. The problem i need
to solve is
explained below,

There are three threads in the player.
1) Master Thread
2) Buffer Thread
3) Play Thread

The master thread should control the other two threads. So Master
thread should
communicate to the Bufffer thread and wait for a response. As soon as
it gets the
response from the Buffer Thread, the master thread should communicate
to the Play thread.
After playing the data, the play thread should send back a message to
the master thread.
Till this message is recieved the master thread should wait.

So the question i have is "How to communicate between threads? How can
we make a thread
wait for other threads response?"

sample code, link Or help in any form is highly appreciated.

Thanks in advance
-Sundar

Reply to this Message

Patricia Shanahan - 10 Nov 2006 15:16 GMT

> Hi,
>
[quoted text clipped - 27 lines]
> Thanks in advance
> -Sundar

Does it have to run on pre-1.5 versions of Java?

If not, look at java.util.concurrent, especially the blocking queues.
They seem ideal for the message passing model of thread communication,
and you expressed your problem in terms of message passing.

Patricia

Reply to this Message

Lew - 11 Nov 2006 19:20 GMT

>> Hi,
>> There are three threads in the player.
[quoted text clipped - 11 lines]
>> the master thread.
>> Till this message is recieved the master thread should wait.

> ... look at java.util.concurrent, especially the blocking queues.
> They seem ideal for the message passing model of thread communication,
> and you expressed your problem in terms of message passing.

If your algorithm is completely synchronous, how will threads help you?

public void play( String audioFile, int blockSize ) // untested
{
FileChannel fc = new FileInputStream( audioFile ).getChannel();

for ( ByteBuffer buffer = ByteBuffer.allocate( blockSize );
fc.read( buffer ) >= 0L; buffer.clear() )
{
buffer.flip();
play( buffer );
}
}

- Lew

- Lew

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ANONYMOUS.COWARD0xC0DE@gmail.com - 11 Nov 2006 06:07 GMT

> Hi,
>
[quoted text clipped - 27 lines]
> Thanks in advance
> -Sundar

java.io.PipedInputStream
java.io.PipedOutputStream

explicit data passing between threads.

or you can use synchronized blocks of code in each thread and use wait
and notify to set variables at appropriate times.

Reply to this Message

Sundar - 11 Nov 2006 06:41 GMT

Thanks for your help.

I took a look into wait() and notify() mothods. Im got stuck and i
could not find a way to use wait and notify. Is there any code snippets
availabe which gives the example of wait and notify methods??

Thanks in advance

-Sundar

> > Hi,
> >
[quoted text clipped - 35 lines]
> or you can use synchronized blocks of code in each thread and use wait
> and notify to set variables at appropriate times.

Reply to this Message

Gordon Beaton - 11 Nov 2006 08:51 GMT

> java.io.PipedInputStream
> java.io.PipedOutputStream
>
> explicit data passing between threads.

That's just silly. There's no need to *stream* data between threads
when you can pass object references or simply call methods in the
target thread.

/gordon

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[ don't email me support questions or followups ]
g o r d o n + n e w s @ b a l d e r 1 3 . s e

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