/*

  * #%L

  * SimpleReconnectStrategy.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.state;

 import java.io.IOException;

 import java.util.List;

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

 import com.allanbank.mongodb.util.IOUtils;

 import com.allanbank.mongodb.util.log.Log;

 import com.allanbank.mongodb.util.log.LogFactory;

 /**

  * SimpleReconnectStrategy provides a reconnection strategy to simply attempt to

  * connect to the server again.

  * 

  * @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 SimpleReconnectStrategy extends AbstractReconnectStrategy {

     /** The logger for the {@link SimpleReconnectStrategy}. */

     protected static final Log LOG = LogFactory

             .getLog(SimpleReconnectStrategy.class);

     /**

      * Creates a new SimpleReconnectStrategy.

      */

     public SimpleReconnectStrategy() {

         super();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to try and connect to every server selected by the

      * ServerSelector until one of the connections is successful.

      * </p>

      */

     @Override

     public Connection reconnect(final Connection oldConnection) {

         // Clear the interrupt state for the thread.

         final boolean wasInterrupted = Thread.interrupted();

         try {

             // First try and connect back to the original server. This will

             // hopefully re-enable the state.

             final Server origServer = myState

                     .get(oldConnection.getServerName());

             Connection newConn = tryConnect(origServer);

             if (newConn != null) {

                 return newConn;

             }

             final List<Server> servers = getSelector().pickServers();

             for (final Server server : servers) {

                 newConn = tryConnect(server);

                 if (newConn != null) {

                     return newConn;

                 }

             }

             LOG.info("Reconnect attempt failed for all {} servers: {}",

                     servers.size(), servers);

         }

         finally {

             // Reset the interrupt state.

             if (wasInterrupted) {

                 Thread.currentThread().interrupt();

             }

         }

         return null;

     }

     /**

      * Tries to connect to the server.

      * 

      * @param server

      *            The server to connect to.

      * @return The connection to the server.

      */

     private Connection tryConnect(final Server server) {

         Connection newConn = null;

         try {

             newConn = getConnectionFactory().connect(server, getConfig());

             if (isConnected(server, newConn)) {

                 LOG.info("Reconnected to {}", server);

                 // Make sure we don't close the connection.

                 final Connection result = newConn;

                 newConn = null;

                 return result;

             }

         }

         catch (final IOException error) {

             // Connection failed. Try the next one.

             LOG.debug("Reconnect to {} failed: {}", server, error.getMessage());

         }

         finally {

             IOUtils.close(newConn);

         }

         return null;

     }

 }