gov.lbl.dsd.sea.nio
Class AsyncPeerHandler

java.lang.Object
  gov.lbl.dsd.sea.EventHandler
      gov.lbl.dsd.sea.nio.AsyncPeerHandler

Direct Known Subclasses:

AsyncEchoServer, AsyncPingPong

public abstract class AsyncPeerHandler

extends EventHandler

Abstract base class simplifying the implementation of asynchronous event handlers sending requests to a peer, and receiving responses from the peer; Assumes an auto-closing peer.

Override protected onXYZ event handling methods for application specific behaviour.

For example, a typical non-blocking peer event handler accumulates partial reads along the following lines:

public class MyPeerHandler extends PeerEventHandler {
        private static final Charset CHARSET = Charset.forName("UTF-8");

        public void onAccepted(ChannelResponse.Accepted rsp) {
                rsp.getKey().attach(new gov.lbl.dsd.sea.nio.util.ByteArrayList());
                rsp.getPeer().enqueue(
                                new ChannelRequest.Register(this.getStage(), rsp.getKey()
                                                .channel(), SelectionKey.OP_READ));
        }

        public void onRead(ChannelResponse.Read rsp) {
                ByteArrayList bytesRead = (ByteArrayList) rsp.getKey().attachment();
                bytesRead.add(rsp.getBuffer());
                rsp.getPeer().getReadBufferPool().put(rsp.getBuffer()); // recycle buffer
                if (bytesRead.size() >= 4) {
                        // message header containing payload length has arrived
                        int payloadLength = bytesRead.getInt(0);
                        if (bytesRead.size() >= 4 + payloadLength) {
                                // we have received the entire variable length payload
                                String payload = bytesRead.getString(4, bytesRead.size(), CHARSET);
                                bytesRead.clear();

                                // do something useful with payload
                                System.out.println(payload);
                        }
                }
        }

        ...
}

Version:

$Revision: 1.18 $, $Date: 2004/06/01 20:47:20 $

Method Summary

void	handle(Object event) Called when an event has been received

Methods inherited from class gov.lbl.dsd.sea.EventHandler

destroy, init

Methods inherited from class java.lang.Object

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

Method Detail

handle

public void handle(Object event)

Called when an event has been received

Specified by:

handle in class EventHandler