Propagate TimeoutException when possible

This allows clients to recover from transient errors.

core/src/main/java/org/jclouds/cache/internal/BackoffExponentiallyAndRetryOnThrowableCacheLoader.java

@@ -23,8 +23,10 @@ import static com.google.common.base.Preconditions.checkNotNull;
 
 import java.util.Map;
 import java.util.concurrent.Callable;
+import java.util.concurrent.TimeoutException;
 
 import org.jclouds.cache.ForwardingCacheLoader;
+import org.jclouds.util.Throwables2;
 
 import com.google.common.annotations.Beta;
 import com.google.common.cache.CacheLoader;
@@ -93,7 +95,16 @@ public class BackoffExponentiallyAndRetryOnThrowableCacheLoader<K, V> extends Fo
 
          @Override
          public V call() throws Exception {
-            return BackoffExponentiallyAndRetryOnThrowableCacheLoader.super.load(key);
+            try {
+               return BackoffExponentiallyAndRetryOnThrowableCacheLoader.super.load(key);
+            } catch (Exception e) {
+               TimeoutException te = Throwables2.getFirstThrowableOfType(e,
+                  TimeoutException.class);
+               if (te != null) {
+                  throw te;
+               }
+               throw e;
+            }
          }
       });
    }

core/src/test/java/org/jclouds/cache/internal/BackoffExponentiallyAndRetryOnThrowableCacheLoaderTest.java

@@ -25,6 +25,9 @@ import static org.easymock.EasyMock.verify;
 import static org.testng.Assert.assertSame;
 import static org.testng.Assert.assertTrue;
 
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeoutException;
+
 import org.jclouds.rest.ResourceNotFoundException;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
@@ -73,4 +76,22 @@ public class BackoffExponentiallyAndRetryOnThrowableCacheLoaderTest {
       }
       verify(mock);
    }
-}
+
+   @Test
+   void testThrowsTimeoutException() throws Exception {
+      int attempts = 3;
+      BackoffExponentiallyAndRetryOnThrowableCacheLoader<String, Boolean> backoff = new BackoffExponentiallyAndRetryOnThrowableCacheLoader<String, Boolean>(
+               ResourceNotFoundException.class, 50l, 500l, attempts, mock);
+
+      expect(mock.load("foo")).andThrow(new ExecutionException(new TimeoutException()));
+
+      replay(mock);
+      try {
+         backoff.load("foo");
+         assertTrue(false);
+      } catch (TimeoutException e) {
+
+      }
+      verify(mock);
+   }
+}