/*

  * #%L

  * AbstractClient.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;

 import java.io.Closeable;

 import java.util.concurrent.atomic.AtomicBoolean;

 import com.allanbank.mongodb.MongoDbException;

 import com.allanbank.mongodb.ReadPreference;

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

 import com.allanbank.mongodb.client.connection.Connection;

 import com.allanbank.mongodb.error.MongoClientClosedException;

 /**

  * AbstractClient provides a base class for {@link Client} implementations.

  * 

  * @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 2012-2014, Allanbank Consulting, Inc., All Rights Reserved

  */

 public abstract class AbstractClient implements Client {

     /** Tracks if the client is closed. */

     private final AtomicBoolean myClosed = new AtomicBoolean(false);

     /**

      * Creates a new AbstractClient.

      */

     public AbstractClient() {

         super();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to close all of the open connections.

      * </p>

      * 

      * @see Closeable#close()

      */

     @Override

     public void close() {

         myClosed.set(true);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to locate the a connection to send the messages and then

      * forward the messages to that connection.

      * </p>

      */

     @Override

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

             final ReplyCallback replyCallback) throws MongoDbException {

         assertOpen(message1);

         findConnection(message1, message2).send(message1, message2,

                 replyCallback);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to locate the a connection to send the message and then

      * forward the message to that connection.

      * </p>

      */

     @Override

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

             throws MongoDbException {

         assertOpen(message);

         findConnection(message, null).send(message, replyCallback);

     }

     /**

      * Locates a {@link Connection} to send a message on.

      * 

      * @param message1

      *            The first message that will be sent. The connection return

      *            should be compatible with all of the messages

      *            {@link ReadPreference}.

      * @param message2

      *            The second message that will be sent. The connection return

      *            should be compatible with all of the messages

      *            {@link ReadPreference}. May be <code>null</code>.

      * 

      * @return The {@link Connection} to send a message on.

      * @throws MongoDbException

      *             In the case of an error finding a {@link Connection}.

      */

     protected abstract Connection findConnection(Message message1,

             Message message2) throws MongoDbException;

     /**

      * Asserts that the command is open.

      * 

      * @param message

      *            The message being sent.

      * @throws MongoClientClosedException

      *             If the client has been closed.

      */

     private void assertOpen(final Message message)

             throws MongoClientClosedException {

         if (myClosed.get()) {

             throw new MongoClientClosedException(message);

         }

     }

 }