| 1 | /** |
| 2 | * Licensed to jclouds, Inc. (jclouds) under one or more |
| 3 | * contributor license agreements. See the NOTICE file |
| 4 | * distributed with this work for additional information |
| 5 | * regarding copyright ownership. jclouds licenses this file |
| 6 | * to you under the Apache License, Version 2.0 (the |
| 7 | * "License"); you may not use this file except in compliance |
| 8 | * with the License. You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, |
| 13 | * software distributed under the License is distributed on an |
| 14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 15 | * KIND, either express or implied. See the License for the |
| 16 | * specific language governing permissions and limitations |
| 17 | * under the License. |
| 18 | */ |
| 19 | package org.jclouds.concurrent; |
| 20 | |
| 21 | import static com.google.common.base.Preconditions.checkNotNull; |
| 22 | |
| 23 | import java.util.concurrent.ExecutionException; |
| 24 | import java.util.concurrent.Executor; |
| 25 | import java.util.concurrent.TimeUnit; |
| 26 | import java.util.concurrent.TimeoutException; |
| 27 | |
| 28 | import com.google.common.base.Function; |
| 29 | import com.google.common.util.concurrent.ListenableFuture; |
| 30 | |
| 31 | /** |
| 32 | * Transforms the exceptions in a future upon get |
| 33 | * |
| 34 | * Temporarily here until the following is resolved: <a |
| 35 | * href="http://code.google.com/p/guava-libraries/issues/detail?id=310"> guava issue 310</a> |
| 36 | * |
| 37 | * @author Adrian Cole |
| 38 | */ |
| 39 | public class ExceptionParsingListenableFuture<T> implements ListenableFuture<T> { |
| 40 | |
| 41 | private final ListenableFuture<T> future; |
| 42 | private final Function<Exception, T> function; |
| 43 | |
| 44 | public static <T> ExceptionParsingListenableFuture<T> create(ListenableFuture<T> future, |
| 45 | Function<Exception, T> function) { |
| 46 | return new ExceptionParsingListenableFuture<T>(future, function); |
| 47 | } |
| 48 | |
| 49 | public ExceptionParsingListenableFuture(ListenableFuture<T> future, Function<Exception, T> function) { |
| 50 | this.future = checkNotNull(future); |
| 51 | this.function = checkNotNull(function); |
| 52 | } |
| 53 | |
| 54 | public boolean cancel(boolean mayInterruptIfRunning) { |
| 55 | return future.cancel(mayInterruptIfRunning); |
| 56 | } |
| 57 | |
| 58 | public T get() throws InterruptedException, ExecutionException { |
| 59 | try { |
| 60 | return future.get(); |
| 61 | } catch (Exception e) { |
| 62 | return attemptConvert(e); |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | private T attemptConvert(Exception e) { |
| 67 | if (e instanceof ExecutionException && e.getCause() instanceof Exception) |
| 68 | return function.apply((Exception) e.getCause()); |
| 69 | return function.apply(e); |
| 70 | } |
| 71 | |
| 72 | public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException { |
| 73 | try { |
| 74 | return future.get(timeout, unit); |
| 75 | } catch (Exception e) { |
| 76 | return attemptConvert(e); |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | public boolean isCancelled() { |
| 81 | return future.isCancelled(); |
| 82 | } |
| 83 | |
| 84 | public boolean isDone() { |
| 85 | return future.isDone(); |
| 86 | } |
| 87 | |
| 88 | @Override |
| 89 | public void addListener(Runnable listener, Executor exec) { |
| 90 | future.addListener(listener, exec); |
| 91 | } |
| 92 | } |