REST + JSON + AMF

So...I was asked to investigate what will it take to output data in AMF to an existing REST endpoint. The idea is that, with just a path info switch, the endpoint can output XML, JSON or AMF i.e. http://server/rest/service/json, http://server/rest/service/amf. And no, a direct BlazeDS integration is not an option :-( So after looking at the BlazeDS source code (you gotta love open source :-) I homed in on the Java15Amf3Output class. It take an output stream as a property and has a writeObject method. Cool ! So given an Address instance:

package com.esri.webamf;

import java.io.Serializable;

public class Address
    implements Serializable
{
    private String m_addr;
    private String m_city;

    public Address()
    {
    }

    public String getAddr()
    {
        return m_addr;
    }

    public void setAddr(final String addr)
    {
        m_addr = addr;
    }

    public String getCity()
    {
        return m_city;
    }

    public void setCity(final String city)
    {
        m_city = city;
    }
}

I can write it to the servlet output stream as follows:

private void writeAMF(
    final HttpServletRequest httpServletRequest,
    final HttpServletResponse httpServletResponse
) throws IOException
{
    final Address address = new Address();
    address.setAddr( httpServletRequest.getParameter("addr"));
    address.setCity( httpServletRequest.getParameter("city"));
    final ByteArrayOutputStream baos = new ByteArrayOutputStream();
    final Amf3Output amf3Output = new Java15Amf3Output(new SerializationContext());
    amf3Output.setOutputStream(baos);
    amf3Output.writeObject(address);
    amf3Output.writeObjectEnd();
    amf3Output.flush();

    httpServletResponse.setContentType(MessageIOConstants.AMF_CONTENT_TYPE);
    httpServletResponse.setContentLength(baos.size());
    baos.writeTo(httpServletResponse.getOutputStream());
}

On the client side, I used a URLStream instance with an AMF3 object encoding to HTTP GET the result as an ActionScript object as follows:

private function load() : void
{
    var urlRequest : URLRequest = new URLRequest( "http://localhost:8080/webamf/rest/amf" );
    var urlVariables : URLVariables = new URLVariables();
    urlVariables.addr = addr.text;
    urlVariables.city = city.text;
    urlRequest.data = urlVariables;

    var urlStream : URLStream = new URLStream();
    urlStream.objectEncoding = ObjectEncoding.AMF3;
    urlStream.addEventListener(Event.COMPLETE, completeHandler );
    urlStream.load( urlRequest );
}
private function completeHandler( event : Event ) : void
{
    var urlStream : URLStream = event.target as URLStream;
    address = urlStream.readObject() as Address;
}

Where Address is tagged as a remote class aliased to the server side Address class:

package com.esri.webamf
{
    [Bindable]
    [RemoteClass(alias="com.esri.webamf.Address")]
    public class Address
    {
        public var addr : String;
        public var city : String;
        
        public function Address()
        {
        }
    }
}

Cool ?