Adding missing files under onlab-netty
diff --git a/utils/netty/src/main/java/org/onlab/netty/AsyncResponse.java b/utils/netty/src/main/java/org/onlab/netty/AsyncResponse.java
new file mode 100644
index 0000000..b2b490e
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/AsyncResponse.java
@@ -0,0 +1,68 @@
+package org.onlab.netty;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * An asynchronous response.
+ * This class provides a base implementation of Response, with methods to retrieve the
+ * result and query to see if the result is ready. The result can only be retrieved when
+ * it is ready and the get methods will block if the result is not ready yet.
+ * @param <T> type of response.
+ */
+public class AsyncResponse<T> implements Response<T> {
+
+ private T value;
+ private boolean done = false;
+ private final long start = System.nanoTime();
+
+ @Override
+ public T get(long timeout, TimeUnit tu) throws TimeoutException {
+ timeout = tu.toNanos(timeout);
+ boolean interrupted = false;
+ try {
+ synchronized (this) {
+ while (!done) {
+ try {
+ long timeRemaining = timeout - (System.nanoTime() - start);
+ if (timeRemaining <= 0) {
+ throw new TimeoutException("Operation timed out.");
+ }
+ TimeUnit.NANOSECONDS.timedWait(this, timeRemaining);
+ } catch (InterruptedException e) {
+ interrupted = true;
+ }
+ }
+ }
+ } finally {
+ if (interrupted) {
+ Thread.currentThread().interrupt();
+ }
+ }
+ return value;
+ }
+
+ @Override
+ public T get() throws InterruptedException {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public boolean isReady() {
+ return done;
+ }
+
+ /**
+ * Sets response value and unblocks any thread blocking on the response to become
+ * available.
+ * @param data response data.
+ */
+ @SuppressWarnings("unchecked")
+ public synchronized void setResponse(Object data) {
+ if (!done) {
+ done = true;
+ value = (T) data;
+ this.notifyAll();
+ }
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/EchoHandler.java b/utils/netty/src/main/java/org/onlab/netty/EchoHandler.java
new file mode 100644
index 0000000..313a448
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/EchoHandler.java
@@ -0,0 +1,15 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+
+/**
+ * Message handler that echos the message back to the sender.
+ */
+public class EchoHandler implements MessageHandler {
+
+ @Override
+ public void handle(Message message) throws IOException {
+ System.out.println("Received: " + message.payload() + ". Echoing it back to the sender.");
+ message.respond(message.payload());
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/Endpoint.java b/utils/netty/src/main/java/org/onlab/netty/Endpoint.java
new file mode 100644
index 0000000..8681093
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/Endpoint.java
@@ -0,0 +1,62 @@
+package org.onlab.netty;
+
+/**
+ * Representation of a TCP/UDP communication end point.
+ */
+public class Endpoint {
+
+ private final int port;
+ private final String host;
+
+ public Endpoint(String host, int port) {
+ this.host = host;
+ this.port = port;
+ }
+
+ public String host() {
+ return host;
+ }
+
+ public int port() {
+ return port;
+ }
+
+ @Override
+ public String toString() {
+ return "Endpoint [port=" + port + ", host=" + host + "]";
+ }
+
+ @Override
+ public int hashCode() {
+ final int prime = 31;
+ int result = 1;
+ result = prime * result + ((host == null) ? 0 : host.hashCode());
+ result = prime * result + port;
+ return result;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) {
+ return true;
+ }
+ if (obj == null) {
+ return false;
+ }
+ if (getClass() != obj.getClass()) {
+ return false;
+ }
+ Endpoint other = (Endpoint) obj;
+ if (host == null) {
+ if (other.host != null) {
+ return false;
+ }
+ } else if (!host.equals(other.host)) {
+ return false;
+ }
+ if (port != other.port) {
+ return false;
+ }
+ return true;
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/InternalMessage.java b/utils/netty/src/main/java/org/onlab/netty/InternalMessage.java
new file mode 100644
index 0000000..bcf6f52
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/InternalMessage.java
@@ -0,0 +1,85 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+
+/**
+ * Internal message representation with additional attributes
+ * for supporting, synchronous request/reply behavior.
+ */
+public final class InternalMessage implements Message {
+
+ private long id;
+ private Endpoint sender;
+ private String type;
+ private Object payload;
+ private transient NettyMessagingService messagingService;
+ public static final String REPLY_MESSAGE_TYPE = "NETTY_MESSAGIG_REQUEST_REPLY";
+
+ // Must be created using the Builder.
+ private InternalMessage() {}
+
+ public long id() {
+ return id;
+ }
+
+ public String type() {
+ return type;
+ }
+
+ public Endpoint sender() {
+ return sender;
+ }
+
+ @Override
+ public Object payload() {
+ return payload;
+ }
+
+ @Override
+ public void respond(Object data) throws IOException {
+ Builder builder = new Builder(messagingService);
+ InternalMessage message = builder.withId(this.id)
+ // FIXME: Sender should be messagingService.localEp.
+ .withSender(this.sender)
+ .withPayload(data)
+ .withType(REPLY_MESSAGE_TYPE)
+ .build();
+ messagingService.sendAsync(sender, message);
+ }
+
+
+ /**
+ * Builder for InternalMessages.
+ */
+ public static class Builder {
+ private InternalMessage message;
+
+ public Builder(NettyMessagingService messagingService) {
+ message = new InternalMessage();
+ message.messagingService = messagingService;
+ }
+
+ public Builder withId(long id) {
+ message.id = id;
+ return this;
+ }
+
+ public Builder withType(String type) {
+ message.type = type;
+ return this;
+ }
+
+ public Builder withSender(Endpoint sender) {
+ message.sender = sender;
+ return this;
+ }
+ public Builder withPayload(Object payload) {
+ message.payload = payload;
+ return this;
+ }
+
+ public InternalMessage build() {
+ return message;
+ }
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/KryoSerializer.java b/utils/netty/src/main/java/org/onlab/netty/KryoSerializer.java
new file mode 100644
index 0000000..73c01a0
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/KryoSerializer.java
@@ -0,0 +1,47 @@
+package org.onlab.netty;
+
+import org.onlab.util.KryoPool;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+/**
+ * Kryo Serializer.
+ */
+public class KryoSerializer implements Serializer {
+
+ private final Logger log = LoggerFactory.getLogger(getClass());
+
+ private KryoPool serializerPool;
+
+ public KryoSerializer() {
+ setupKryoPool();
+ }
+
+ /**
+ * Sets up the common serialzers pool.
+ */
+ protected void setupKryoPool() {
+ // FIXME Slice out types used in common to separate pool/namespace.
+ serializerPool = KryoPool.newBuilder()
+ .register(ArrayList.class,
+ HashMap.class,
+ ArrayList.class
+ )
+ .build()
+ .populate(1);
+ }
+
+
+ @Override
+ public Object decode(byte[] data) {
+ return serializerPool.deserialize(data);
+ }
+
+ @Override
+ public byte[] encode(Object payload) {
+ return serializerPool.serialize(payload);
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/LoggingHandler.java b/utils/netty/src/main/java/org/onlab/netty/LoggingHandler.java
new file mode 100644
index 0000000..ed6cdb4
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/LoggingHandler.java
@@ -0,0 +1,12 @@
+package org.onlab.netty;
+
+/**
+ * A MessageHandler that simply logs the information.
+ */
+public class LoggingHandler implements MessageHandler {
+
+ @Override
+ public void handle(Message message) {
+ System.out.println("Received: " + message.payload());
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/Message.java b/utils/netty/src/main/java/org/onlab/netty/Message.java
new file mode 100644
index 0000000..54b9526
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/Message.java
@@ -0,0 +1,23 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+
+/**
+ * A unit of communication.
+ * Has a payload. Also supports a feature to respond back to the sender.
+ */
+public interface Message {
+
+ /**
+ * Returns the payload of this message.
+ * @return message payload.
+ */
+ public Object payload();
+
+ /**
+ * Sends a reply back to the sender of this messge.
+ * @param data payload of the response.
+ * @throws IOException if there is a communication error.
+ */
+ public void respond(Object data) throws IOException;
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/MessageDecoder.java b/utils/netty/src/main/java/org/onlab/netty/MessageDecoder.java
new file mode 100644
index 0000000..ecf2d62
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/MessageDecoder.java
@@ -0,0 +1,58 @@
+package org.onlab.netty;
+
+import java.util.Arrays;
+import java.util.List;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+
+/**
+ * Decode bytes into a InternalMessage.
+ */
+public class MessageDecoder extends ByteToMessageDecoder {
+
+ private final NettyMessagingService messagingService;
+ private final Serializer serializer;
+
+ public MessageDecoder(NettyMessagingService messagingService, Serializer serializer) {
+ this.messagingService = messagingService;
+ this.serializer = serializer;
+ }
+
+ @Override
+ protected void decode(ChannelHandlerContext context, ByteBuf in,
+ List<Object> messages) throws Exception {
+
+ byte[] preamble = in.readBytes(MessageEncoder.PREAMBLE.length).array();
+ checkState(Arrays.equals(MessageEncoder.PREAMBLE, preamble), "Message has wrong preamble");
+
+ // read message Id.
+ long id = in.readLong();
+
+ // read message type; first read size and then bytes.
+ String type = new String(in.readBytes(in.readInt()).array());
+
+ // read sender host name; first read size and then bytes.
+ String host = new String(in.readBytes(in.readInt()).array());
+
+ // read sender port.
+ int port = in.readInt();
+
+ Endpoint sender = new Endpoint(host, port);
+
+ // read message payload; first read size and then bytes.
+ Object payload = serializer.decode(in.readBytes(in.readInt()).array());
+
+ InternalMessage message = new InternalMessage.Builder(messagingService)
+ .withId(id)
+ .withSender(sender)
+ .withType(type)
+ .withPayload(payload)
+ .build();
+
+ messages.add(message);
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/MessageEncoder.java b/utils/netty/src/main/java/org/onlab/netty/MessageEncoder.java
new file mode 100644
index 0000000..1b52a0f
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/MessageEncoder.java
@@ -0,0 +1,60 @@
+package org.onlab.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+
+/**
+ * Encode InternalMessage out into a byte buffer.
+ */
+public class MessageEncoder extends MessageToByteEncoder<InternalMessage> {
+
+ // onosiscool in ascii
+ public static final byte[] PREAMBLE = "onosiscool".getBytes();
+
+ private final Serializer serializer;
+
+ public MessageEncoder(Serializer serializer) {
+ this.serializer = serializer;
+ }
+
+ @Override
+ protected void encode(ChannelHandlerContext context, InternalMessage message,
+ ByteBuf out) throws Exception {
+
+ // write preamble
+ out.writeBytes(PREAMBLE);
+
+ // write id
+ out.writeLong(message.id());
+
+ // write type length
+ out.writeInt(message.type().length());
+
+ // write type
+ out.writeBytes(message.type().getBytes());
+
+ // write sender host name size
+ out.writeInt(message.sender().host().length());
+
+ // write sender host name.
+ out.writeBytes(message.sender().host().getBytes());
+
+ // write port
+ out.writeInt(message.sender().port());
+
+ try {
+ serializer.encode(message.payload());
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ byte[] payload = serializer.encode(message.payload());
+
+ // write payload length.
+ out.writeInt(payload.length);
+
+ // write payload bytes
+ out.writeBytes(payload);
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/MessageHandler.java b/utils/netty/src/main/java/org/onlab/netty/MessageHandler.java
new file mode 100644
index 0000000..7bd5a7f
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/MessageHandler.java
@@ -0,0 +1,16 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+
+/**
+ * Handler for a message.
+ */
+public interface MessageHandler {
+
+ /**
+ * Handles the message.
+ * @param message message.
+ * @throws IOException.
+ */
+ public void handle(Message message) throws IOException;
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/MessagingService.java b/utils/netty/src/main/java/org/onlab/netty/MessagingService.java
new file mode 100644
index 0000000..ebad442
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/MessagingService.java
@@ -0,0 +1,41 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+
+/**
+ * Interface for low level messaging primitives.
+ */
+public interface MessagingService {
+ /**
+ * Sends a message asynchronously to the specified communication end point.
+ * The message is specified using the type and payload.
+ * @param ep end point to send the message to.
+ * @param type type of message.
+ * @param payload message payload.
+ * @throws IOException
+ */
+ public void sendAsync(Endpoint ep, String type, Object payload) throws IOException;
+
+ /**
+ * Sends a message synchronously and waits for a response.
+ * @param ep end point to send the message to.
+ * @param type type of message.
+ * @param payload message payload.
+ * @return a response future
+ * @throws IOException
+ */
+ public <T> Response<T> sendAndReceive(Endpoint ep, String type, Object payload) throws IOException;
+
+ /**
+ * Registers a new message handler for message type.
+ * @param type message type.
+ * @param handler message handler
+ */
+ public void registerHandler(String type, MessageHandler handler);
+
+ /**
+ * Unregister current handler, if one exists for message type.
+ * @param type message type
+ */
+ public void unregisterHandler(String type);
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
new file mode 100644
index 0000000..54da8cc
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/NettyMessagingService.java
@@ -0,0 +1,244 @@
+package org.onlab.netty;
+
+import java.io.IOException;
+import java.net.UnknownHostException;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.TimeUnit;
+
+import io.netty.bootstrap.Bootstrap;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.buffer.PooledByteBufAllocator;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.channel.socket.nio.NioSocketChannel;
+
+import org.apache.commons.lang.math.RandomUtils;
+import org.apache.commons.pool.KeyedObjectPool;
+import org.apache.commons.pool.KeyedPoolableObjectFactory;
+import org.apache.commons.pool.impl.GenericKeyedObjectPool;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+
+/**
+ * A Netty based implementation of MessagingService.
+ */
+public class NettyMessagingService implements MessagingService {
+
+ private final Logger log = LoggerFactory.getLogger(getClass());
+
+ private KeyedObjectPool<Endpoint, Channel> channels =
+ new GenericKeyedObjectPool<Endpoint, Channel>(new OnosCommunicationChannelFactory());
+ private final int port;
+ private final EventLoopGroup bossGroup = new NioEventLoopGroup();
+ private final EventLoopGroup workerGroup = new NioEventLoopGroup();
+ private final ConcurrentMap<String, MessageHandler> handlers = new ConcurrentHashMap<>();
+ private Cache<Long, AsyncResponse<?>> responseFutures;
+ private final Endpoint localEp;
+
+ protected Serializer serializer;
+
+ public NettyMessagingService() {
+ // TODO: Default port should be configurable.
+ this(8080);
+ }
+
+ // FIXME: Constructor should not throw exceptions.
+ public NettyMessagingService(int port) {
+ this.port = port;
+ try {
+ localEp = new Endpoint(java.net.InetAddress.getLocalHost().getHostName(), port);
+ } catch (UnknownHostException e) {
+ // bailing out.
+ throw new RuntimeException(e);
+ }
+ }
+
+ public void activate() throws Exception {
+ responseFutures = CacheBuilder.newBuilder()
+ .maximumSize(100000)
+ .weakValues()
+ // TODO: Once the entry expires, notify blocking threads (if any).
+ .expireAfterWrite(10, TimeUnit.MINUTES)
+ .build();
+ startAcceptingConnections();
+ }
+
+ public void deactivate() throws Exception {
+ channels.close();
+ bossGroup.shutdownGracefully();
+ workerGroup.shutdownGracefully();
+ }
+
+ @Override
+ public void sendAsync(Endpoint ep, String type, Object payload) throws IOException {
+ InternalMessage message = new InternalMessage.Builder(this)
+ .withId(RandomUtils.nextLong())
+ .withSender(localEp)
+ .withType(type)
+ .withPayload(payload)
+ .build();
+ sendAsync(ep, message);
+ }
+
+ protected void sendAsync(Endpoint ep, InternalMessage message) throws IOException {
+ Channel channel = null;
+ try {
+ channel = channels.borrowObject(ep);
+ channel.eventLoop().execute(new WriteTask(channel, message));
+ } catch (Exception e) {
+ throw new IOException(e);
+ } finally {
+ try {
+ channels.returnObject(ep, channel);
+ } catch (Exception e) {
+ log.warn("Error returning object back to the pool", e);
+ // ignored.
+ }
+ }
+ }
+
+ @Override
+ public <T> Response<T> sendAndReceive(Endpoint ep, String type, Object payload)
+ throws IOException {
+ AsyncResponse<T> futureResponse = new AsyncResponse<T>();
+ Long messageId = RandomUtils.nextLong();
+ responseFutures.put(messageId, futureResponse);
+ InternalMessage message = new InternalMessage.Builder(this)
+ .withId(messageId)
+ .withSender(localEp)
+ .withType(type)
+ .withPayload(payload)
+ .build();
+ sendAsync(ep, message);
+ return futureResponse;
+ }
+
+ @Override
+ public void registerHandler(String type, MessageHandler handler) {
+ // TODO: Is this the right semantics for handler registration?
+ handlers.putIfAbsent(type, handler);
+ }
+
+ public void unregisterHandler(String type) {
+ handlers.remove(type);
+ }
+
+ private MessageHandler getMessageHandler(String type) {
+ return handlers.get(type);
+ }
+
+ private void startAcceptingConnections() throws InterruptedException {
+ ServerBootstrap b = new ServerBootstrap();
+ b.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
+ b.group(bossGroup, workerGroup)
+ .channel(NioServerSocketChannel.class)
+ .childHandler(new OnosCommunicationChannelInitializer())
+ .option(ChannelOption.SO_BACKLOG, 128)
+ .childOption(ChannelOption.SO_KEEPALIVE, true);
+
+ // Bind and start to accept incoming connections.
+ b.bind(port).sync();
+ }
+
+ private class OnosCommunicationChannelFactory
+ implements KeyedPoolableObjectFactory<Endpoint, Channel> {
+
+ @Override
+ public void activateObject(Endpoint endpoint, Channel channel)
+ throws Exception {
+ }
+
+ @Override
+ public void destroyObject(Endpoint ep, Channel channel) throws Exception {
+ channel.close();
+ }
+
+ @Override
+ public Channel makeObject(Endpoint ep) throws Exception {
+ Bootstrap b = new Bootstrap();
+ b.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
+ b.group(workerGroup);
+ // TODO: Make this faster:
+ // http://normanmaurer.me/presentations/2014-facebook-eng-netty/slides.html#37.0
+ b.channel(NioSocketChannel.class);
+ b.option(ChannelOption.SO_KEEPALIVE, true);
+ b.handler(new OnosCommunicationChannelInitializer());
+
+ // Start the client.
+ ChannelFuture f = b.connect(ep.host(), ep.port()).sync();
+ return f.channel();
+ }
+
+ @Override
+ public void passivateObject(Endpoint ep, Channel channel)
+ throws Exception {
+ }
+
+ @Override
+ public boolean validateObject(Endpoint ep, Channel channel) {
+ return channel.isOpen();
+ }
+ }
+
+ private class OnosCommunicationChannelInitializer extends ChannelInitializer<SocketChannel> {
+
+ @Override
+ protected void initChannel(SocketChannel channel) throws Exception {
+ channel.pipeline()
+ .addLast(new MessageEncoder(serializer))
+ .addLast(new MessageDecoder(NettyMessagingService.this, serializer))
+ .addLast(new NettyMessagingService.InboundMessageDispatcher());
+ }
+ }
+
+ private class WriteTask implements Runnable {
+
+ private final Object message;
+ private final Channel channel;
+
+ public WriteTask(Channel channel, Object message) {
+ this.message = message;
+ this.channel = channel;
+ }
+
+ @Override
+ public void run() {
+ channel.writeAndFlush(message);
+ }
+ }
+
+ private class InboundMessageDispatcher extends SimpleChannelInboundHandler<InternalMessage> {
+
+ @Override
+ protected void channelRead0(ChannelHandlerContext ctx, InternalMessage message) throws Exception {
+ String type = message.type();
+ if (type.equals(InternalMessage.REPLY_MESSAGE_TYPE)) {
+ try {
+ AsyncResponse<?> futureResponse =
+ NettyMessagingService.this.responseFutures.getIfPresent(message.id());
+ if (futureResponse != null) {
+ futureResponse.setResponse(message.payload());
+ }
+ log.warn("Received a reply. But was unable to locate the request handle");
+ } finally {
+ NettyMessagingService.this.responseFutures.invalidate(message.id());
+ }
+ return;
+ }
+ MessageHandler handler = NettyMessagingService.this.getMessageHandler(type);
+ handler.handle(message);
+ }
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/Response.java b/utils/netty/src/main/java/org/onlab/netty/Response.java
new file mode 100644
index 0000000..04675ce
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/Response.java
@@ -0,0 +1,36 @@
+package org.onlab.netty;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * Response object returned when making synchronous requests.
+ * Can you used to check is a response is ready and/or wait for a response
+ * to become available.
+ *
+ * @param <T> type of response.
+ */
+public interface Response<T> {
+
+ /**
+ * Gets the response waiting for a designated timeout period.
+ * @param timeout timeout period (since request was sent out)
+ * @param tu unit of time.
+ * @return response
+ * @throws TimeoutException if the timeout expires before the response arrives.
+ */
+ public T get(long timeout, TimeUnit tu) throws TimeoutException;
+
+ /**
+ * Gets the response waiting for indefinite timeout period.
+ * @return response
+ * @throws InterruptedException if the thread is interrupted before the response arrives.
+ */
+ public T get() throws InterruptedException;
+
+ /**
+ * Checks if the response is ready without blocking.
+ * @return true if response is ready, false otherwise.
+ */
+ public boolean isReady();
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/Serializer.java b/utils/netty/src/main/java/org/onlab/netty/Serializer.java
new file mode 100644
index 0000000..ac55f5a
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/Serializer.java
@@ -0,0 +1,24 @@
+package org.onlab.netty;
+
+/**
+ * Interface for encoding/decoding message payloads.
+ */
+public interface Serializer {
+
+ /**
+ * Decodes the specified byte array to a POJO.
+ *
+ * @param data byte array.
+ * @return POJO
+ */
+ Object decode(byte[] data);
+
+ /**
+ * Encodes the specified POJO into a byte array.
+ *
+ * @param data POJO to be encoded
+ * @return byte array.
+ */
+ byte[] encode(Object message);
+
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/SimpleClient.java b/utils/netty/src/main/java/org/onlab/netty/SimpleClient.java
new file mode 100644
index 0000000..1573780
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/SimpleClient.java
@@ -0,0 +1,24 @@
+package org.onlab.netty;
+
+import java.util.concurrent.TimeUnit;
+
+public final class SimpleClient {
+ private SimpleClient() {}
+
+ public static void main(String... args) throws Exception {
+ NettyMessagingService messaging = new TestNettyMessagingService(9081);
+ messaging.activate();
+
+ messaging.sendAsync(new Endpoint("localhost", 8080), "simple", "Hello World");
+ Response<String> response = messaging.sendAndReceive(new Endpoint("localhost", 8080), "echo", "Hello World");
+ System.out.println("Got back:" + response.get(2, TimeUnit.SECONDS));
+ }
+
+ public static class TestNettyMessagingService extends NettyMessagingService {
+ public TestNettyMessagingService(int port) throws Exception {
+ super(port);
+ Serializer serializer = new KryoSerializer();
+ this.serializer = serializer;
+ }
+ }
+}
diff --git a/utils/netty/src/main/java/org/onlab/netty/SimpleServer.java b/utils/netty/src/main/java/org/onlab/netty/SimpleServer.java
new file mode 100644
index 0000000..12fa025
--- /dev/null
+++ b/utils/netty/src/main/java/org/onlab/netty/SimpleServer.java
@@ -0,0 +1,19 @@
+package org.onlab.netty;
+
+public final class SimpleServer {
+ private SimpleServer() {}
+
+ public static void main(String... args) throws Exception {
+ NettyMessagingService server = new TestNettyMessagingService();
+ server.activate();
+ server.registerHandler("simple", new LoggingHandler());
+ server.registerHandler("echo", new EchoHandler());
+ }
+
+ public static class TestNettyMessagingService extends NettyMessagingService {
+ protected TestNettyMessagingService() {
+ Serializer serializer = new KryoSerializer();
+ this.serializer = serializer;
+ }
+ }
+}