package jettyserver;

import java.io.IOException;

import javax.servlet.AsyncContext;
import javax.servlet.ReadListener;
import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import config.SocketConfigurationConstants;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.server.handler.AbstractHandler;

public class AsyncJettyServer
{

    public static void main(String[] args) throws Exception
    {
        Server server = new Server();
        server.setHandler(new AsyncHttpHandler());
        ServerConnector httpConnector = new ServerConnector(server);
        httpConnector.setPort(SocketConfigurationConstants.HTTP_SERVER_PORT);
        server.addConnector(httpConnector);
        server.start();
        server.join();
    }

    static class AsyncHttpHandler extends AbstractHandler
    {

        @Override
        public void handle(String target, Request baseRequest, HttpServletRequest request, final HttpServletResponse response) throws IOException, ServletException
        {
            if (response.isCommitted() || baseRequest.isHandled())
            {
                return;
            }

            baseRequest.setHandled(true);
            final AsyncContext asyncContext = request.startAsync(request, response);
            final ServletInputStream input = asyncContext.getRequest().getInputStream();
            final ServletOutputStream output = asyncContext.getResponse().getOutputStream();
            asyncContext.setTimeout(0);

            response.setContentType(request.getContentType());
            Echoer echoer = new Echoer(asyncContext);
            input.setReadListener(echoer);
            output.setWriteListener(echoer);
        }
    }

    private static class Echoer implements ReadListener, WriteListener
    {

        private final byte[] buffer = new byte[1024 * 4];
        private final AsyncContext asyncContext;
        private final ServletInputStream input;
        private final ServletOutputStream output;
        private boolean complete;

        private Echoer(AsyncContext asyncContext) throws IOException
        {
            this.asyncContext = asyncContext;
            this.input = asyncContext.getRequest().getInputStream();
            this.output = asyncContext.getResponse().getOutputStream();
        }

        @Override
        public void onDataAvailable() throws IOException
        {
            while (input.isReady())
            {
                int read = input.read(buffer);
                output.write(buffer, 0, read);
                if (!output.isReady())
                {
                    return;
                }
            }
            if (input.isFinished())
            {
                complete = true;
                asyncContext.complete();
            }
        }

        @Override
        public void onAllDataRead() throws IOException
        {
        }

        @Override
        public void onWritePossible() throws IOException
        {
            if (input.isFinished())
            {
                if (!complete)
                {
                    asyncContext.complete();
                }
            }
            else
            {
                onDataAvailable();
            }
        }

        @Override
        public void onError(Throwable failure)
        {
            failure.printStackTrace();
        }
    }
}