/*

  * #%L

  * FutureUtils.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.util;

 import java.util.concurrent.ExecutionException;

 import java.util.concurrent.Future;

 import com.allanbank.mongodb.MongoDbException;

 /**

  * FutureUtils provides helper methods for dealing with {@link Future}s.

  * 

  * @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 final class FutureUtils {

     /**

      * Unwraps the contents of the Future.

      * 

      * @param <T>

      *            The type of the future and response.

      * @param future

      *            The future value to get.

      * @return The response from the Future.

      * @throws MongoDbException

      *             On an error from the Future.

      */

     public static <T> T unwrap(final Future<T> future) {

         try {

             return future.get();

         }

         catch (final InterruptedException e) {

             e.fillInStackTrace();

             throw new MongoDbException(e);

         }

         catch (final ExecutionException e) {

             final Throwable cause = e.getCause();

             cause.fillInStackTrace();

             if (cause instanceof MongoDbException) {

                 throw (MongoDbException) cause;

             }

             throw new MongoDbException(cause);

         }

     }

     /**

      * Stop creation of a new FutureUtils.

      */

     private FutureUtils() {

         // Nothing.

     }

 }