/*

  * #%L

  * SerialClientImpl.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 com.allanbank.mongodb.Durability;

 import com.allanbank.mongodb.MongoClientConfiguration;

 import com.allanbank.mongodb.MongoCursorControl;

 import com.allanbank.mongodb.MongoDbException;

 import com.allanbank.mongodb.MongoIterator;

 import com.allanbank.mongodb.ReadPreference;

 import com.allanbank.mongodb.StreamCallback;

 import com.allanbank.mongodb.bson.Document;

 import com.allanbank.mongodb.bson.DocumentAssignable;

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

 /**

  * A specialization of the {@link ClientImpl} to always try to use the same

  * connection.

  * 

  * @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 2012-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class SerialClientImpl extends AbstractClient {

     /** If true then assertions have been enabled for the class. */

     protected static final boolean ASSERTIONS_ENABLED;

     static {

         ASSERTIONS_ENABLED = SerialClientImpl.class.desiredAssertionStatus();

     }

     /** The current active Connection to the MongoDB Servers. */

     private Connection myConnection;

     /** The delegate client for accessing connections. */

     private final ClientImpl myDelegate;

     /**

      * Create a new SerialClientImpl.

      * 

      * @param client

      *            The delegate client for accessing connections.

      */

     public SerialClientImpl(final ClientImpl client) {

         myDelegate = client;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to close all of the open connections.

      * </p>

      * 

      * @see Closeable#close()

      */

     @Override

     public void close() {

         super.close();

         // Don't close the delegate.

         myConnection = null;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return the cluster stats from the delegate client.

      * </p>

      */

     @Override

     public ClusterStats getClusterStats() {

         return myDelegate.getClusterStats();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return the {@link ClusterType} of delegate

      * {@link ClientImpl}.

      * </p>

      */

     @Override

     public ClusterType getClusterType() {

         return myDelegate.getClusterType();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return the configuration used when the client was

      * constructed.

      * </p>

      */

     @Override

     public MongoClientConfiguration getConfig() {

         return myDelegate.getConfig();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return the configurations default durability.

      * </p>

      * 

      * @see Client#getDefaultDurability()

      */

     @Override

     public Durability getDefaultDurability() {

         return myDelegate.getDefaultDurability();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return the configurations default read preference.

      * </p>

      * 

      * @see Client#getDefaultReadPreference()

      */

     @Override

     public ReadPreference getDefaultReadPreference() {

         return myDelegate.getDefaultReadPreference();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to forward to the delegate client.

      * </p>

      * 

      * @see Client#restart(DocumentAssignable)

      */

     @Override

     public MongoIterator<Document> restart(

             final DocumentAssignable cursorDocument)

             throws IllegalArgumentException {

         return myDelegate.restart(cursorDocument);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to forward to the delegate client.

      * </p>

      * 

      * @see Client#restart(StreamCallback, DocumentAssignable)

      */

     @Override

     public MongoCursorControl restart(final StreamCallback<Document> results,

             final DocumentAssignable cursorDocument)

             throws IllegalArgumentException {

         return myDelegate.restart(results, cursorDocument);

     }

     /**

      * Tries to reuse the last connection used. If the connection it closed or

      * does not exist then the request is delegated to the {@link ClientImpl}

      * and the result cached for future requests.

      * 

      * @return The found connection.

      * @throws MongoDbException

      *             On a failure to talk to the MongoDB servers.

      */

     @Override

     protected Connection findConnection(final Message message1,

             final Message message2) throws MongoDbException {

         if ((myConnection == null) || !myConnection.isAvailable()) {

             myConnection = myDelegate.findConnection(message1, message2);

         }

         return myConnection;

     }

 }