HADOOP-9792. Merge 1508313 from branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1508315 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -71,6 +71,9 @@ Release 2.1.0-beta - 2013-07-02
     HADOOP-9762. RetryCache utility for implementing RPC retries. 
     (Suresh Srinivas via jing9)
 
+    HADOOP-9792. Retry the methods that are tagged @AtMostOnce along 
+    with @Idempotent. (suresh)
+
   IMPROVEMENTS
 
     HADOOP-9164. Print paths of loaded native libraries in

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/FailoverProxyProvider.java

@@ -51,8 +51,8 @@ public interface FailoverProxyProvider<T> extends Closeable {
   /**
    * Return a reference to the interface this provider's proxy objects actually
    * implement. If any of the methods on this interface are annotated as being
-   * {@link Idempotent}, then this fact will be passed to the
-   * {@link RetryPolicy#shouldRetry(Exception, int, int, boolean)} method on
+   * {@link Idempotent} or {@link AtMostOnce}, then this fact will be passed to
+   * the {@link RetryPolicy#shouldRetry(Exception, int, int, boolean)} method on
    * error, for use in determining whether or not failover should be attempted.
    * 
    * @return the interface implemented by the proxy objects returned by

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java

@@ -53,7 +53,7 @@ class RetryInvocationHandler implements RpcInvocationHandler {
   private final Map<String,RetryPolicy> methodNameToPolicyMap;
   private Object currentProxy;
 
-  RetryInvocationHandler(FailoverProxyProvider proxyProvider,
+  protected RetryInvocationHandler(FailoverProxyProvider proxyProvider,
       RetryPolicy retryPolicy) {
     this(proxyProvider, retryPolicy, Collections.<String, RetryPolicy>emptyMap());
   }
@@ -97,11 +97,16 @@ class RetryInvocationHandler implements RpcInvocationHandler {
         hasMadeASuccessfulCall = true;
         return ret;
       } catch (Exception e) {
-        boolean isMethodIdempotent = proxyProvider.getInterface()
+        boolean isIdempotentOrAtMostOnce = proxyProvider.getInterface()
             .getMethod(method.getName(), method.getParameterTypes())
             .isAnnotationPresent(Idempotent.class);
+        if (!isIdempotentOrAtMostOnce) {
+          isIdempotentOrAtMostOnce = proxyProvider.getInterface()
+              .getMethod(method.getName(), method.getParameterTypes())
+              .isAnnotationPresent(AtMostOnce.class);
+        }
         RetryAction action = policy.shouldRetry(e, retries++,
-            invocationFailoverCount, isMethodIdempotent);
+            invocationFailoverCount, isIdempotentOrAtMostOnce);
         if (action.action == RetryAction.RetryDecision.FAIL) {
           if (action.reason != null) {
             LOG.warn("Exception while invoking " + 
@@ -169,7 +174,7 @@ class RetryInvocationHandler implements RpcInvocationHandler {
     }
   }
   
-  private Object invokeMethod(Method method, Object[] args) throws Throwable {
+  protected Object invokeMethod(Method method, Object[] args) throws Throwable {
     try {
       if (!method.isAccessible()) {
         method.setAccessible(true);

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryPolicies.java

@@ -153,7 +153,7 @@ public class RetryPolicies {
   static class TryOnceThenFail implements RetryPolicy {
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       return RetryAction.FAIL;
     }
   }
@@ -161,7 +161,7 @@ public class RetryPolicies {
   static class RetryForever implements RetryPolicy {
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       return RetryAction.RETRY;
     }
   }
@@ -196,7 +196,7 @@ public class RetryPolicies {
 
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       if (retries >= maxRetries) {
         return RetryAction.FAIL;
       }
@@ -305,7 +305,7 @@ public class RetryPolicies {
 
     @Override
     public RetryAction shouldRetry(Exception e, int curRetry, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       final Pair p = searchPair(curRetry);
       if (p == null) {
         //no more retries.
@@ -435,12 +435,12 @@ public class RetryPolicies {
 
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       RetryPolicy policy = exceptionToPolicyMap.get(e.getClass());
       if (policy == null) {
         policy = defaultPolicy;
       }
-      return policy.shouldRetry(e, retries, failovers, isMethodIdempotent);
+      return policy.shouldRetry(e, retries, failovers, isIdempotentOrAtMostOnce);
     }
     
   }
@@ -463,7 +463,7 @@ public class RetryPolicies {
 
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) throws Exception {
+        boolean isIdempotentOrAtMostOnce) throws Exception {
       RetryPolicy policy = null;
       if (e instanceof RemoteException) {
         policy = exceptionNameToPolicyMap.get(
@@ -472,7 +472,7 @@ public class RetryPolicies {
       if (policy == null) {
         policy = defaultPolicy;
       }
-      return policy.shouldRetry(e, retries, failovers, isMethodIdempotent);
+      return policy.shouldRetry(e, retries, failovers, isIdempotentOrAtMostOnce);
     }
   }
   
@@ -533,7 +533,7 @@ public class RetryPolicies {
 
     @Override
     public RetryAction shouldRetry(Exception e, int retries,
-        int failovers, boolean isMethodIdempotent) throws Exception {
+        int failovers, boolean isIdempotentOrAtMostOnce) throws Exception {
       if (failovers >= maxFailovers) {
         return new RetryAction(RetryAction.RetryDecision.FAIL, 0,
             "failovers (" + failovers + ") exceeded maximum allowed ("
@@ -553,7 +553,7 @@ public class RetryPolicies {
                 calculateExponentialTime(delayMillis, failovers, maxDelayBase));
       } else if (e instanceof SocketException ||
                  (e instanceof IOException && !(e instanceof RemoteException))) {
-        if (isMethodIdempotent) {
+        if (isIdempotentOrAtMostOnce) {
           return RetryAction.FAILOVER_AND_RETRY;
         } else {
           return new RetryAction(RetryAction.RetryDecision.FAIL, 0,
@@ -562,7 +562,7 @@ public class RetryPolicies {
         }
       } else {
         return fallbackPolicy.shouldRetry(e, retries, failovers,
-            isMethodIdempotent);
+            isIdempotentOrAtMostOnce);
       }
     }
     

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryPolicy.java

@@ -75,24 +75,25 @@ public interface RetryPolicy {
   
   /**
    * <p>
-   * Determines whether the framework should retry a
-   * method for the given exception, and the number
-   * of retries that have been made for that operation
+   * Determines whether the framework should retry a method for the given
+   * exception, and the number of retries that have been made for that operation
    * so far.
    * </p>
+   * 
    * @param e The exception that caused the method to fail
    * @param retries The number of times the method has been retried
    * @param failovers The number of times the method has failed over to a
-   *   different backend implementation
-   * @param isMethodIdempotent <code>true</code> if the method is idempotent
-   *   and so can reasonably be retried on failover when we don't know if the
-   *   previous attempt reached the server or not
+   *          different backend implementation
+   * @param isIdempotentOrAtMostOnce <code>true</code> if the method is
+   *          {@link Idempotent} or {@link AtMostOnce} and so can reasonably be
+   *          retried on failover when we don't know if the previous attempt
+   *          reached the server or not
    * @return <code>true</code> if the method should be retried,
-   *   <code>false</code> if the method should not be retried
-   *   but shouldn't fail with an exception (only for void methods)
-   * @throws Exception The re-thrown exception <code>e</code> indicating
-   *   that the method failed and should not be retried further
+   *         <code>false</code> if the method should not be retried but
+   *         shouldn't fail with an exception (only for void methods)
+   * @throws Exception The re-thrown exception <code>e</code> indicating that
+   *           the method failed and should not be retried further
    */
   public RetryAction shouldRetry(Exception e, int retries, int failovers,
-      boolean isMethodIdempotent) throws Exception;
+      boolean isIdempotentOrAtMostOnce) throws Exception;
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/retry/TestFailoverProxy.java

@@ -78,7 +78,7 @@ public class TestFailoverProxy {
 
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,
-        boolean isMethodIdempotent) {
+        boolean isIdempotentOrAtMostOnce) {
       return failovers < 1 ? RetryAction.FAILOVER_AND_RETRY : RetryAction.FAIL;
     }