/*

  * #%L

  * CursorCallback.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.callback;

 import java.util.concurrent.atomic.AtomicBoolean;

 import com.allanbank.mongodb.Callback;

 import com.allanbank.mongodb.MongoDbException;

 import com.allanbank.mongodb.MongoIterator;

 import com.allanbank.mongodb.bson.Document;

 import com.allanbank.mongodb.client.Client;

 import com.allanbank.mongodb.client.MongoIteratorImpl;

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

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

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

 /**

  * Callback to convert a {@link CursorableMessage} {@link Reply} into a

  * {@link MongoIteratorImpl}.

  * 

  * @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 2011-2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public final class CursorCallback extends

         AbstractReplyCallback<MongoIterator<Document>> implements AddressAware {

     /** The server the original request was sent to. */

     private volatile String myAddress;

     /** The original query. */

     private final Client myClient;

     /** If true then the callback should expect a command formated cursor reply. */

     private final boolean myCommand;

     /** The original message to start the cursor. */

     private final CursorableMessage myMessage;

     /** The reply to the query. */

     private volatile Reply myReply;

     /**

      * Initially set to false. Set to true for the first of address or reply

      * being set. The second fails and {@link #trigger() triggers} the callback.

      */

     private final AtomicBoolean mySetOther;

     /**

      * Create a new CursorCallback.

      * 

      * @param client

      *            The client interface to the server.

      * @param message

      *            The original query.

      * @param command

      *            If true then the callback should expect a command formated

      *            cursor reply.

      * @param results

      *            The callback to update once the first set of results are

      *            ready.

      */

     public CursorCallback(final Client client, final CursorableMessage message,

             final boolean command,

             final Callback<MongoIterator<Document>> results) {

         super(results);

         myClient = client;

         myMessage = message;

         myCommand = command;

         mySetOther = new AtomicBoolean(false);

     }

     /**

      * Returns the server the original request was sent to.

      * 

      * @return The server the original request was sent to.

      */

     public String getAddress() {

         return myAddress;

     }

     /**

      * Sets the value of the server the original request was sent to.

      * 

      * @param address

      *            The new value for the server the original request was sent to.

      */

     @Override

     public void setAddress(final String address) {

         myAddress = address;

         trigger();

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to add the {@link Query} to the exception.

      * </p>

      * 

      * @see AbstractReplyCallback#asError(Reply, int, int, String)

      */

     @Override

     protected MongoDbException asError(final Reply reply, final int okValue,

             final int errorNumber, final String errorMessage) {

         return super.asError(reply, okValue, errorNumber, false, errorMessage,

                 myMessage);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to construct a {@link MongoIteratorImpl} around the reply.

      * </p>

      * 

      * @see AbstractReplyCallback#convert(Reply)

      */

     @Override

     protected MongoIterator<Document> convert(final Reply reply)

             throws MongoDbException {

         Reply result = reply;

         if (isCommand()) {

             result = CommandCursorTranslator.translate(reply);

         }

         return new MongoIteratorImpl(myMessage, myClient, myAddress, result);

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to check if the server address has been set and if so then

      * pass the converted reply to the {@link #getForwardCallback() forward

      * callback}. Otherwise the call is dropped.

      * </p>

      */

     @Override

     protected void handle(final Reply reply) {

         myReply = reply;

         trigger();

     }

     /**

      * Returns true if the callback should expect a command formated cursor

      * reply.

      * 

      * @return True if the callback should expect a command formated cursor

      *         reply.

      */

     protected boolean isCommand() {

         return myCommand;

     }

     /**

      * Triggers the callback when the address and reply are set.

      */

     private void trigger() {

         if (!mySetOther.compareAndSet(false, true)) {

             super.handle(myReply);

         }

     }

 }