Grizzly Port unification

Looks like one of my anticipated features in Grizzly is finally here in their latest version 1.6.1: Port Unification. According to this javalobby article, port unification has been implemented and can now be used in glassfish v3. For OpenESB users this means consolidating the HTTP ports between glassfish v2 and the HTTP BC. What this also means is being able to accomplish the same thing in the RSS BC since we use grizzly to service the HTTP GET requests for feeds.

One of the nice benefits this adds to glassfish v3 is the ability to now consume only one port verses 2 or 3. Now phobos, comet, and jruby can run on the same port and grizzly can determine the correct Adapter.

To stay current with this RSS BC enhancement watch issue #8: https://rss-bc.dev.java.net/issues/show_bug.cgi?id=8

Using Grizzly to create a simple HTTP listener

Today I would like to show how you can use Grizzly, a NIO framework for building scalable applications, to create a simple listener to service HTTP requests/responses. My main goal is to provide a simple example, because currently there is a lack of documentation on how to use this great framework (see jean's blog); although they have just made the javadocs available online.

My team and I have been working recently on developing a JBI Binding Component for RSS. To service the incoming HTTP GETs we decided to use Grizzly. Thankfully you can accomplish this with minimal effort.

The following is a simple example to start a TCP listener and respond with some simple text.

import com.sun.grizzly.http.SelectorThread;
import com.sun.grizzly.tcp.Adapter;
import com.sun.grizzly.tcp.OutputBuffer;
import com.sun.grizzly.tcp.Request;
import com.sun.grizzly.tcp.Response;
import com.sun.grizzly.util.buf.ByteChunk;

import java.net.HttpURLConnection;

public class EmbeddedServer implements Adapter {

public static void main(String[] args) {
    SelectorThread st = new SelectorThread();
    st.setPort(8282);
    st.setAdapter(new EmbeddedServer());
    try {
        st.initEndpoint();
        st.startEndpoint();
    } catch (Exception e) {
        System.out.println("Exception in SelectorThread: " + e);
    } finally {
        if (st.isRunning()) {
            st.stopEndpoint();
        }
    }
}

public void service(Request request, Response response)
        throws Exception {
    String requestURI = request.requestURI().toString();

    System.out.println("New incoming request with URI: " + requestURI);
    System.out.println("Request Method is: " + request.method());

    if (request.method().toString().equalsIgnoreCase("GET")) {
        response.setStatus(HttpURLConnection.HTTP_OK);
        byte[] bytes = "Here is my response text".getBytes();

        ByteChunk chunk = new ByteChunk();
        response.setContentLength(bytes.length);
        response.setContentType("text/plain");
        chunk.append(bytes, 0, bytes.length);
        OutputBuffer buffer = response.getOutputBuffer();
        buffer.doWrite(chunk, response);
        response.finish();
    }
}

public void afterService(Request request, Response response)
        throws Exception {
    request.recycle();
    response.recycle();
}

public void fireAdapterEvent(String string, Object object) {}
}

That's basically it in a nutshell. So far Grizzly has worked out well for us and is currently being used in Glassfish and Sailfin.

As a side note I have also been reading a lot about groovy recently, so as an added bonus and a personal challenge to write my first groovy script, here is the equivalent groovy code. Remember that groovy scripts can use existing java classes and can also be consumed by java classes.

import com.sun.grizzly.http.SelectorThread
import com.sun.grizzly.tcp.Adapter
import com.sun.grizzly.tcp.Request
import com.sun.grizzly.tcp.Response
import com.sun.grizzly.util.buf.ByteChunk
import java.net.HttpURLConnection

class BasicAdapter implements Adapter {
  public void service(Request request, Response response) {
      def requestURI = request.requestURI().toString()

      println 'New incoming request with URI: ' + requestURI
      println 'Request Method is: ' + request.method()

      if (request.method().toString().equalsIgnoreCase("GET")) {
          response.status = HttpURLConnection.HTTP_OK
          def bytes = 'Here is my response text'.bytes

          def chunk = new ByteChunk();
          response.contentLength = bytes.length
          response.contentType = 'text/plain'
          chunk.append(bytes, 0, bytes.length)
          def buffer = response.outputBuffer
          buffer.doWrite(chunk, response)
          response.finish()
      }
  }

  public void afterService(Request request, Response response) {
      request.recycle()
      response.recycle()
  }

  public void fireAdapterEvent(string, object) {}
}

def st = new SelectorThread()
st.port = 8282
st.adapter = new BasicAdapter()
try {
  st.initEndpoint()
  st.startEndpoint()
} finally {
  if (st.isRunning()) {
      st.stopEndpoint()
  }
}