org.agilewiki.jactor

Class JAIterator

java.lang.Object

org.agilewiki.jactor.JAIterator

Direct Known Subclasses:

_Iterator

public abstract class JAIterator
extends Object

Iterates over its process method and works within any actor which supports 2-way messages.

We can use JAIterator to calculate factorials:

        final int max = 5;
        RP printResult = new RP() {
            public void process(Object rsp) {
                System.out.println(rsp);
            }
        };

        (new JAIterator() {
            int i;
            int r = 1;

            public void process(RP rp) throws Exception {
                if (i >= max) rp.process(new Integer(r));
                else {
                    i += 1;
                    r = r * i;
                    rp.process(null);
                }
            }
        }).iterate(printResult);
 

The JAIterator.process method is called repeatedly until it returns a non-null response, which is then returned by JAIterator. However, the response need not be returned immediately, so the JAIterator.process method can send messages to other actors:

 public class Factorial extends JLPCActor {

     public Factorial(Mailbox mailbox) {
         super(mailbox);
     }

     protected void processRequest(Object req, final RP rp)
             throws Exception {
         final int max = 5;
         RP printResult = new RP() {
             public void process(Object rsp) throws Exception {
                 System.out.println(rsp);
                 rp.process(null);
             }
         };
         (new JAIterator() {
             int i;
             int r = 1;
             Multiplier mp = new Multiplier(getMailbox());

             protected void process(RP rp) throws Exception {
                 if (i >= max) rp.process(new Integer(r));
                 else {
                     i += 1;
                     Multiply m = new Multiply();
                     m.a = r;
                     m.b = i;
                     send(mp, m, new RP() {
                         public void process(Object rsp) throws Exception {
                             r = ((Integer) rsp).intValue();
                         }
                     });
                     rp.process(null);
                 }
             }
         }).iterate(printResult);
     }
 }
 

Constructor Summary

Constructors

Constructor and Description
JAIterator()

Method Summary

Methods

Modifier and Type	Method and Description
void	iterate(RP responseProcessor) Iterates over the process method.
protected abstract void	process(RP responseProcessor) Perform an iteration.

Methods inherited from class java.lang.Object

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

Constructor Detail

JAIterator

public JAIterator()

Method Detail

iterate

public void iterate(RP responseProcessor)
             throws Exception

Iterates over the process method.

Parameters:

responseProcessor - The response processor.

Throws:

Exception - Any uncaught exceptions raised by the process method.

process

protected abstract void process(RP responseProcessor)
                         throws Exception

Perform an iteration.

Parameters:

responseProcessor - Processes the response.

Throws:

Exception - Any uncaught exceptions raised by the process method.