org.jcsp.plugNplay

Class Plex2

java.lang.Object

org.jcsp.plugNplay.Plex2

All Implemented Interfaces:

CSProcess

public final class Plex2
extends java.lang.Object
implements CSProcess

Fair multiplexes two Object streams into one.

Process Diagram

    in0  _______
   -->--|       | out
    in1 | Plex2 |-->--
   -->--|_______|
 

Description

Plex2 is a process whose output stream is a fair multiplexing of its input streams. It makes no assumptions about the traffic patterns occuring on the input streams and ensures that no input stream will be starved by busy siblings. It guarantees that if an input stream has data pending, no other stream will be serviced twice before that data is serviced.

Channel Protocols

Input Channels
in0, in1	java.lang.Object	The input streams.
Output Channels
out	java.lang.Object	The multiplexed output stream.

Example

The following example shows how to use Plex2 in a small program. The program also uses some of the other plugNplay processes.

 import org.jcsp.lang.*;
 import org.jcsp.plugNplay.*;
 
 public class Plex2Example {
 
   public static void main (String[] argv) {
 
     final One2OneChannel[] a = Channel.one2oneArray (2);
     final One2OneChannel[] b = Channel.one2oneArray (2);
     final One2OneChannel c = Channel.one2one ();
 
     new Parallel (
       new CSProcess[] {
         new Fibonacci (a[0].out ()),
         new Squares (a[1].out ()),
         new Sign ("Fibonacci ", a[0].in (), b[0].out ()),
         new Sign ("              Squares ", a[1].in (), b[1].out ()),
         new Plex2 (b[0].in (), b[1].in (), c.out ()),
         new Printer (c.in (), "", "\n")
       }
     ).run ();
 
   }
 
 }
 

Implemntation Note

For information, here is the run method for this process:

   public void run () {
     AltingChannelInput[] input = {in0, in1};         // in0 and in1 are the input channels
     Alternative alt = new Alternative (input);
     while (true) {
       out.write (input[alt.fairSelect ()].read ());  // out is the output channel
     }
   }
 

Author:

P.H. Welch

See Also:

Plex, Multiplex

Constructor Summary

Constructors

Constructor and Description
Plex2(AltingChannelInput in0, AltingChannelInput in1, ChannelOutput out) Construct a new Plex2 process with the input channels in0 and in1 and the output channel out.

Method Summary

Modifier and Type	Method and Description
void	run() The main body of this process.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Plex2

public Plex2(AltingChannelInput in0,
             AltingChannelInput in1,
             ChannelOutput out)

Construct a new Plex2 process with the input channels in0 and in1 and the output channel out. The ordering of the input channels makes no difference to the behaviour of this process.

Parameters:

in0 - an input channel

in1 - an input channel

out - the output channel

Method Detail

run

public void run()

The main body of this process.

Specified by:

run in interface CSProcess