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Copyright Tristan Aubrey-Jones May 2008.
Abstract: A project investigating and developing an implicitly concurrent programming language, based on a metaphor taken from the physical world is reported. Uses a programming paradigm where programs consist of systems of autonomous agents, or active objects which communicate via message passing. A language enhancing Java with actors and linear types is presented. Example programs are written, compiled, and executed to evaluate the usefulness of the language. The language found to provide a familiar notation for implicit parallelism, and a compelling new model for concurrency, combining the performance of shared variables with the elegance of message passing.
Introductory Slides (PDF),
Report (PDF),
ActiveJava compiler prototype (ajavac),
ActiveJava runtime library (ajava_lang).
Examples:
calc - pocket calculator actor program
dining - dining philosophers actor program (never deadlocks)
sort - parallel quicksort implementation ("SortBenchmark" sorts 10,000 random integers using actors, java threads, and sequentially and compares)
To compile examples use:compile.bat ./calc compile.bat ./sort compile.bat ./diningTo run examples use:
run ./calc Main run ./dining Main run ./dining Main fast run ./sort Main run ./sort SortingBenchmark
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import org.taj.ajava.lang.*;
public class AFrame extends AComponent
{
protected JFrame frame;
protected AContainer contentPane;
public AFrame(String title)
{
super(new JFrame(title));
frame = ((JFrame)component);
Container cp = frame.getContentPane();
contentPane = new AContainer(cp);
}
public AFrame()
{
this("AJava Window");
}
public static class Show
{
}
private void react_0(Show cmd)
{
frame.show();
}
public void deliver(Show cmd)
{
bufferMessage(new org.taj.ajava.runtime.ActorMessage(cmd, 0));
}
protected void react(Show cmd)
{
react_0(cmd);
}
public static class Hide
{
}
private void react_1(Hide cmd)
{
frame.hide();
}
public void deliver(Hide cmd)
{
bufferMessage(new org.taj.ajava.runtime.ActorMessage(cmd, 1));
}
protected void react(Hide cmd)
{
react_1(cmd);
}
public static class SetCloseOperation
{
public static final int DO_NOTHING_ON_CLOSE = WindowConstants.DO_NOTHING_ON_CLOSE;
public static final int EXIT_ON_CLOSE = WindowConstants.EXIT_ON_CLOSE;
public static final int HIDE_ON_CLOSE = WindowConstants.HIDE_ON_CLOSE;
public int op;
public SetCloseOperation(int op)
{
this.op = op;
}
}
private void react_2(SetCloseOperation s)
{
frame.setDefaultCloseOperation(s.op);
}
public void deliver(SetCloseOperation s)
{
bufferMessage(new org.taj.ajava.runtime.ActorMessage(s, 2));
}
protected void react(SetCloseOperation s)
{
react_2(s);
}
protected void processMessage(org.taj.ajava.runtime.ActorMessage msg)
{
switch (msg.reactorId) {
case 0:
{
react_0(((Show)msg.payload));
return;
}
case 1:
{
react_1(((Hide)msg.payload));
return;
}
case 2:
{
react_2(((SetCloseOperation)msg.payload));
return;
}
default:
{
super.processMessage(msg);
return;
}
}
}
}