no.antares.clutil.hitman.MessageChannel.java Source code

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Here is the source code for no.antares.clutil.hitman.MessageChannel.java

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/* MessageChannel.java
   Copyright 2012 Tommy Skodje (http://www.antares.no)
    
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
    
   http://www.apache.org/licenses/LICENSE-2.0
    
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/
package no.antares.clutil.hitman;

import java.io.*;
import java.net.*;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

/** Channel for receiving and sending Message(s).
 * @author tommy skodje
 */
public class MessageChannel implements Closeable {
    private static final Logger logger = Logger.getLogger(MessageChannel.class.getName());
    private final ServerSocket serverSocket;

    /** Send message to HitMan */
    public static String send(int port, String message) throws IOException {
        return send("localhost", port, message);
    }

    /** Send message to HitMan, @return response */
    public static String send(String host, int port, String message) throws IOException {
        Socket kkSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;
        try {
            kkSocket = new Socket(host, port);
            out = new PrintWriter(kkSocket.getOutputStream(), true);
            out.println(message);

            if (StringUtils.isBlank(reply2(message)))
                return "";

            in = new BufferedReader(new InputStreamReader(kkSocket.getInputStream()));
            StringBuffer reply = new StringBuffer();
            String fromServer;
            while ((fromServer = in.readLine()) != null) {
                logger.trace("received: " + fromServer);
                reply.append(fromServer);
            }
            return reply.toString();
        } catch (ConnectException e) {
            logger.warn("send(" + message + ") could not connect to: " + host + ":" + port);
            throw e;
        } catch (IOException e) {
            logger.warn("send(" + message + ") could not send to: " + host + ":" + port);
            throw e;
        } finally {
            close(out);
            close(in);
            close(kkSocket);
        }
    }

    /** Open a channel - close when done */
    public static MessageChannel openInbound(int port) {
        try {
            return new MessageChannel(new ServerSocket(port));
        } catch (IOException e) {
            logger.fatal("(): " + port, e);
            throw new RuntimeException("Could not listen on port: " + port, e);
        }
    }

    private MessageChannel(ServerSocket serverSocket) {
        this.serverSocket = serverSocket;
    }

    /** Close the channel */
    public void close() {
        try {
            if (serverSocket != null)
                serverSocket.close();
        } catch (IOException ioe) {
        }
    }

    /** Blocks while waiting for message */
    protected Message waitForNextMessage() {
        Socket clientSocket = null;
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            clientSocket = serverSocket.accept();
            in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            String inputLine = in.readLine();
            if (inputLine != null) {
                String reply = reply2(inputLine);
                if (!StringUtils.isBlank(reply)) {
                    out = new PrintWriter(clientSocket.getOutputStream(), true);
                    out.println(reply);
                }
                Message msg = new Message(inputLine);
                return msg;
            }
        } catch (IOException e) {
            logger.error("waitForNextMessage() got Exception", e);
        } finally {
            close(clientSocket);
            close(out);
            close(in);
        }
        return Message.EMPTY;
    }

    private static String reply2(String msg) {
        if (Message.Semafor.PING.msgStart.equals(msg))
            return "PONG";
        return null;
    }

    private static void close(Closeable s) {
        try {
            if (s != null)
                s.close();
        } catch (IOException ioe) {
        }
    }

    private static void close(Socket s) {
        try {
            if (s != null)
                s.close();
        } catch (IOException ioe) {
        }
    }

}