| 1 | /** |
| 2 | * |
| 3 | * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com> |
| 4 | * |
| 5 | * ==================================================================== |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * 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, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | * ==================================================================== |
| 18 | */ |
| 19 | package org.jclouds.rest.suppliers; |
| 20 | |
| 21 | import static com.google.common.base.Suppliers.memoizeWithExpiration; |
| 22 | |
| 23 | import java.util.concurrent.TimeUnit; |
| 24 | import java.util.concurrent.atomic.AtomicReference; |
| 25 | |
| 26 | import org.jclouds.concurrent.RetryOnTimeOutExceptionSupplier; |
| 27 | import org.jclouds.rest.AuthorizationException; |
| 28 | |
| 29 | import com.google.common.base.Supplier; |
| 30 | |
| 31 | /** |
| 32 | * This will retry the supplier if it encounters a timeout exception, but not if it encounters an |
| 33 | * AuthorizationException. |
| 34 | * <p/> |
| 35 | * A shared exception reference is used so that anyone who encounters an authorizationexception will |
| 36 | * be short-circuited. This prevents accounts from being locked out. |
| 37 | * |
| 38 | * <h3>details</h3> |
| 39 | * http://code.google.com/p/google-guice/issues/detail?id=483 guice doesn't remember when singleton |
| 40 | * providers throw exceptions. in this case, if the supplier fails with an authorization exception, |
| 41 | * it is called again for each provider method that depends on it. To short-circuit this, we |
| 42 | * remember the last exception trusting that guice is single-threaded. |
| 43 | * |
| 44 | * @author Adrian Cole |
| 45 | */ |
| 46 | public class MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier<T> implements Supplier<T> { |
| 47 | private final Supplier<T> delegate; |
| 48 | private final long seconds; |
| 49 | |
| 50 | public MemoizedRetryOnTimeOutButNotOnAuthorizationExceptionSupplier( |
| 51 | AtomicReference<AuthorizationException> authException, long seconds, Supplier<T> delegate) { |
| 52 | this.delegate = memoizeWithExpiration(new RetryOnTimeOutExceptionSupplier<T>( |
| 53 | new SetAndThrowAuthorizationExceptionSupplier<T>(delegate, authException)), seconds, TimeUnit.SECONDS); |
| 54 | this.seconds = seconds; |
| 55 | } |
| 56 | |
| 57 | @Override |
| 58 | public T get() { |
| 59 | return delegate.get(); |
| 60 | } |
| 61 | |
| 62 | @Override |
| 63 | public String toString() { |
| 64 | return "memoizeWithExpiration(" + delegate + ", seconds=" + seconds + ")"; |
| 65 | } |
| 66 | } |