/*

  * #%L

  * AbstractReplyCallback.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 com.allanbank.mongodb.Callback;

 import com.allanbank.mongodb.MongoDbException;

 import com.allanbank.mongodb.client.FutureCallback;

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

 /**

  * Helper class for constructing callbacks that convert a {@link Reply} message

  * into a different type of result.

  * 

  * @param <F>

  *            The type for the converted {@link Reply}.

  * 

  * @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 abstract class AbstractReplyCallback<F> extends

         AbstractValidatingReplyCallback {

     /** The callback for the converted type. */

     final Callback<F> myForwardCallback;

     /**

      * Create a new AbstractReplyCallback.

      * 

      * @param forwardCallback

      *            The callback for the converted type.

      */

     public AbstractReplyCallback(final Callback<F> forwardCallback) {

         myForwardCallback = forwardCallback;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to forward the exception to the {@link #myForwardCallback}.

      * </p>

      * 

      * @see Callback#exception

      */

     @Override

     public void exception(final Throwable thrown) {

         getForwardCallback().exception(thrown);

     }

     /**

      * Returns the forwardCallback value.

      * 

      * @return the forwardCallback

      */

     public Callback<F> getForwardCallback() {

         return myForwardCallback;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to return true if the {@link #getForwardCallback()

      * forwardCallback} is a {@link FutureCallback} or to forward the call if

      * the {@code forwardCallback} is a {@link ReplyCallback}.

      * </p>

      */

     @Override

     public boolean isLightWeight() {

         return (myForwardCallback instanceof FutureCallback)

                 || ((myForwardCallback instanceof ReplyCallback) && ((ReplyCallback) myForwardCallback)

                         .isLightWeight());

     }

     /**

      * Converts the {@link Reply} into the final response type.

      * 

      * @param reply

      *            The reply to convert.

      * @return The converted reply.

      * @throws MongoDbException

      *             On a failure converting the reply. Generally, the

      *             {@link #verify(Reply)} method should be used to report

      *             errors.

      */

     protected abstract F convert(Reply reply) throws MongoDbException;

     /**

      * {@inheritDoc}

      * <p>

      * Overriden to {@link #convert(Reply) convert} and then pass the converted

      * reply to the {@link #getForwardCallback() forward callback}.

      * </p>

      */

     @Override

     protected void handle(final Reply reply) {

         getForwardCallback().callback(convert(reply));

     }

 }