/*

  * #%L

  * TwoThreadSocketConnection.java - mongodb-async-driver - Allanbank Consulting, Inc.

  * %%

  * Copyright (C) 2011 - 2014 Allanbank Consulting, Inc.

  * %%

  * 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.

  * #L%

  */

 package com.allanbank.mongodb.client.connection.socket;

 import java.io.IOException;

 import java.net.SocketException;

 import com.allanbank.mongodb.MongoClientConfiguration;

 import com.allanbank.mongodb.MongoDbException;

 import com.allanbank.mongodb.bson.io.BufferingBsonOutputStream;

 import com.allanbank.mongodb.bson.io.RandomAccessOutputStream;

 import com.allanbank.mongodb.bson.io.StringDecoderCache;

 import com.allanbank.mongodb.bson.io.StringEncoderCache;

 import com.allanbank.mongodb.client.Message;

 import com.allanbank.mongodb.client.callback.AddressAware;

 import com.allanbank.mongodb.client.callback.ReplyCallback;

 import com.allanbank.mongodb.client.message.BuildInfo;

 import com.allanbank.mongodb.client.message.PendingMessage;

 import com.allanbank.mongodb.client.message.PendingMessageQueue;

 import com.allanbank.mongodb.client.state.Server;

 import com.allanbank.mongodb.client.state.ServerUpdateCallback;

 import com.allanbank.mongodb.util.IOUtils;

 /**

  * Provides a blocking Socket based connection to a MongoDB server.

  * <p>

  * This version uses a pair of threads (1 send and 1 receive) to handle the

  * messages going to and from MongoDB.

  * </p>

  * <p>

  * This implementation was the default for the driver through the 1.2.3 release.

  * It is still used by the driver for communication sockets that are not know to

  * be standard Java Sockets as it performs better when the communication path

  * does not have built in buffering of messages.

  * </p>

  * 

  * @api.no This class is <b>NOT</b> part of the drivers API. This class may be

  *         mutated in incompatible ways between any two releases of the driver.

  * @copyright 2011-2014, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class TwoThreadSocketConnection extends AbstractSocketConnection {

     /** The writer for BSON documents. */

     protected final BufferingBsonOutputStream myBsonOut;

     /** The queue of messages to be sent. */

     protected final PendingMessageQueue myToSendQueue;

     /** The thread receiving replies. */

     private final Thread myReceiver;

     /** The thread sending messages. */

     private final Thread mySender;

     /**

      * Creates a new SocketConnection to a MongoDB server.

      * 

      * @param server

      *            The MongoDB server to connect to.

      * @param config

      *            The configuration for the Connection to the MongoDB server.

      * @throws SocketException

      *             On a failure connecting to the MongoDB server.

      * @throws IOException

      *             On a failure to read or write data to the MongoDB server.

      */

     public TwoThreadSocketConnection(final Server server,

             final MongoClientConfiguration config) throws SocketException,

             IOException {

         this(server, config, new StringEncoderCache(), new StringDecoderCache());

     }

     /**

      * Creates a new SocketConnection to a MongoDB server.

      * 

      * @param server

      *            The MongoDB server to connect to.

      * @param config

      *            The configuration for the Connection to the MongoDB server.

      * @param encoderCache

      *            Cache used for encoding strings.

      * @param decoderCache

      *            Cache used for decoding strings.

      * @throws SocketException

      *             On a failure connecting to the MongoDB server.

      * @throws IOException

      *             On a failure to read or write data to the MongoDB server.

      */

     public TwoThreadSocketConnection(final Server server,

             final MongoClientConfiguration config,

             final StringEncoderCache encoderCache,

             final StringDecoderCache decoderCache) throws SocketException,

             IOException {

         super(server, config, encoderCache, decoderCache);

         myBsonOut = new BufferingBsonOutputStream(new RandomAccessOutputStream(

                 encoderCache));

         myToSendQueue = new PendingMessageQueue(

                 config.getMaxPendingOperationsPerConnection(),

                 config.getLockType());

         myReceiver = config.getThreadFactory().newThread(

                 new ReceiveRunnable(this));

         myReceiver.setDaemon(true);

         myReceiver.setName("MongoDB " + mySocket.getLocalPort() + "<--"

                 + myServer.getCanonicalName());

         mySender = config.getThreadFactory().newThread(new SendRunnable());

         mySender.setDaemon(true);

         mySender.setName("MongoDB " + mySocket.getLocalPort() + "-->"

                 + myServer.getCanonicalName());

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void close() throws IOException {

         final boolean wasOpen = myOpen.get();

         myOpen.set(false);

         mySender.interrupt();

         myReceiver.interrupt();

         try {

             if (Thread.currentThread() != mySender) {

                 mySender.join();

             }

         }

         catch (final InterruptedException ie) {

             // Ignore.

         }

         finally {

             // Now that output is shutdown. Close up the socket. This

             // Triggers the receiver to close if the interrupt didn't work.

             myOutput.close();

             myInput.close();

             mySocket.close();

         }

         try {

             if (Thread.currentThread() != myReceiver) {

                 myReceiver.join();

             }

         }

         catch (final InterruptedException ie) {

             // Ignore.

         }

         myEventSupport.firePropertyChange(OPEN_PROP_NAME, wasOpen, false);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public int getPendingCount() {

         return super.getPendingCount() + myToSendQueue.size();

     }

     /**

      * {@inheritDoc}

      * <p>

      * True if the send and pending queues are empty.

      * </p>

      */

     @Override

     public boolean isIdle() {

         return super.isIdle() && myToSendQueue.isEmpty();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Notifies the appropriate messages of the error.

      * </p>

      */

     @Override

     public void raiseErrors(final MongoDbException exception) {

         final PendingMessage message = new PendingMessage();

         while (myToSendQueue.poll(message)) {

             raiseError(exception, message.getReplyCallback());

         }

         super.raiseErrors(exception);

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void send(final Message message1, final Message message2,

             final ReplyCallback replyCallback) throws MongoDbException {

         validate(message1, message2);

         if (replyCallback instanceof AddressAware) {

             ((AddressAware) replyCallback).setAddress(myServer

                     .getCanonicalName());

         }

         try {

             myToSendQueue.put(message1, null, message2, replyCallback);

         }

         catch (final InterruptedException e) {

             throw new MongoDbException(e);

         }

     }

     /**

      * {@inheritDoc}

      */

     @Override

     public void send(final Message message, final ReplyCallback replyCallback)

             throws MongoDbException {

         validate(message, null);

         if (replyCallback instanceof AddressAware) {

             ((AddressAware) replyCallback).setAddress(myServer

                     .getCanonicalName());

         }

         try {

             myToSendQueue.put(message, replyCallback);

         }

         catch (final InterruptedException e) {

             throw new MongoDbException(e);

         }

     }

     /**

      * Starts the connections read and write threads.

      */

     @Override

     public void start() {

         myReceiver.start();

         mySender.start();

         if (myServer.needBuildInfo()) {

             send(new BuildInfo(), new ServerUpdateCallback(myServer));

         }

     }

     /**

      * Runnable to push data out over the MongoDB connection.

      * 

      * @copyright 2011, Allanbank Consulting, Inc., All Rights Reserved

      */

     protected class SendRunnable implements Runnable {

         /** Tracks if there are messages in the buffer that need to be flushed. */

         private boolean myNeedToFlush = false;

         /** The {@link PendingMessage} used for the local cached copy. */

         private final PendingMessage myPendingMessage = new PendingMessage();

         /**

          * {@inheritDoc}

          * <p>

          * Overridden to pull messages off the

          * {@link TwoThreadSocketConnection#myToSendQueue} and push them into

          * the socket connection. If <code>null</code> is ever received from a

          * poll of the queue then the socket connection is flushed and blocking

          * call is made to the queue.

          * </p>

          * 

          * @see Runnable#run()

          */

         @Override

         public void run() {

             boolean sawError = false;

             try {

                 while (myOpen.get() && !sawError) {

                     try {

                         sendOne();

                     }

                     catch (final InterruptedException ie) {

                         // Handled by loop but if we have a message, need to

                         // tell him something bad happened (but we shouldn't).

                         raiseError(ie, myPendingMessage.getReplyCallback());

                     }

                     catch (final IOException ioe) {

                         myLog.warn(ioe, "I/O Error sending a message.");

                         raiseError(ioe, myPendingMessage.getReplyCallback());

                         sawError = true;

                     }

                     catch (final RuntimeException re) {

                         myLog.warn(re, "Runtime error sending a message.");

                         raiseError(re, myPendingMessage.getReplyCallback());

                         sawError = true;

                     }

                     catch (final Error error) {

                         myLog.error(error, "Error sending a message.");

                         raiseError(error, myPendingMessage.getReplyCallback());

                         sawError = true;

                     }

                     finally {

                         myPendingMessage.clear();

                     }

                 }

             }

             finally {

                 // This may/will fail because we are dying.

                 try {

                     if (myOpen.get()) {

                         doFlush();

                     }

                 }

                 catch (final IOException ioe) {

                     myLog.warn(ioe, "I/O Error on final flush of messages.");

                 }

                 finally {

                     // Make sure we get shutdown completely.

                     IOUtils.close(TwoThreadSocketConnection.this);

                 }

             }

         }

         /**

          * Flushes the messages in the buffer and clears the need-to-flush flag.

          * 

          * @throws IOException

          *             On a failure flushing the messages.

          */

         protected final void doFlush() throws IOException {

             if (myNeedToFlush) {

                 flush();

                 myNeedToFlush = false;

             }

         }

         /**

          * Sends a single message.

          * 

          * @throws InterruptedException

          *             If the thread is interrupted waiting for a message to

          *             send.

          * @throws IOException

          *             On a failure sending the message.

          */

         protected final void sendOne() throws InterruptedException, IOException {

             boolean took = false;

             if (myNeedToFlush) {

                 took = myToSendQueue.poll(myPendingMessage);

             }

             else {

                 myToSendQueue.take(myPendingMessage);

                 took = true;

             }

             if (took) {

                 myNeedToFlush = true;

                 myPendingMessage.getMessage().write(

                         myPendingMessage.getMessageId(), myBsonOut);

                 send(myPendingMessage, myBsonOut.getOutput());

                 // We have handed the message off. Not our problem any more.

                 // We could legitimately do this before the send but in the case

                 // of an I/O error the send's exception is more meaningful then

                 // the receivers generic "Didn't get a reply".

                 myPendingMessage.clear();

             }

             else {

                 doFlush();

             }

         }

     }

 }