/*

  * #%L

  * IteratorToListCallbackAdapter.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.ArrayList;

 import java.util.List;

 import com.allanbank.mongodb.Callback;

 import com.allanbank.mongodb.MongoIterator;

 import com.allanbank.mongodb.bson.Document;

 import com.allanbank.mongodb.util.IOUtils;

 /**

  * IteratorToListCallbackAdapter provides the ability to translate a

  * MongoIterator callback into a list callback.

  * 

  * @copyright 2013, Allanbank Consulting, Inc., All Rights Reserved

  */

 public class IteratorToListCallbackAdapter implements

         Callback<MongoIterator<Document>> {

     /** The list callback to invoke once all of the documents are collected. */

     private final Callback<List<Document>> myDelegate;

     /**

      * Creates a new IteratorToListCallbackAdapter.

      * 

      * @param delegate

      *            The list callback to invoke once all of the documents are

      *            collected.

      */

     public IteratorToListCallbackAdapter(final Callback<List<Document>> delegate) {

         myDelegate = delegate;

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to collect all of the results and then call the delegate.

      * </p>

      */

     @Override

     public void callback(final MongoIterator<Document> result) {

         final List<Document> docs = new ArrayList<Document>();

         try {

             while (result.hasNext()) {

                 docs.add(result.next());

             }

         }

         finally {

             IOUtils.close(result);

             myDelegate.callback(docs);

         }

     }

     /**

      * {@inheritDoc}

      * <p>

      * Overridden to forward to the delegate.

      * </p>

      */

     @Override

     public void exception(final Throwable thrown) {

         myDelegate.exception(thrown);

     }

 }