HADOOP-12386. RetryPolicies.RETRY_FOREVER should be able to specify a retry interval. (Sunil G via wangda)

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

@@ -1072,6 +1072,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12087. [JDK8] Fix javadoc errors caused by incorrect or illegal
     tags. (Akira AJISAKA via stevel).
 
+    HADOOP-12386. RetryPolicies.RETRY_FOREVER should be able to specify a 
+    retry interval. (Sunil G via wangda)
+
   OPTIMIZATIONS
 
     HADOOP-12051. ProtobufRpcEngine.invoke() should use Exception.toString()

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

@@ -63,6 +63,17 @@ public class RetryPolicies {
    */
   public static final RetryPolicy RETRY_FOREVER = new RetryForever();
 
+  /**
+   * <p>
+   * Keep trying forever with a fixed time between attempts.
+   * </p>
+   */
+  public static final RetryPolicy retryForeverWithFixedSleep(long sleepTime,
+      TimeUnit timeUnit) {
+    return new RetryUpToMaximumCountWithFixedSleep(Integer.MAX_VALUE,
+        sleepTime, timeUnit);
+  }
+
   /**
    * <p>
    * Keep trying a limited number of times, waiting a fixed time between attempts,
@@ -151,7 +162,7 @@ public class RetryPolicies {
     return new FailoverOnNetworkExceptionRetry(fallbackPolicy, maxFailovers,
         maxRetries, delayMillis, maxDelayBase);
   }
-  
+
   static class TryOnceThenFail implements RetryPolicy {
     @Override
     public RetryAction shouldRetry(Exception e, int retries, int failovers,

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

@@ -25,6 +25,7 @@ import static org.apache.hadoop.io.retry.RetryPolicies.retryByRemoteException;
 import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumCountWithFixedSleep;
 import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumCountWithProportionalSleep;
 import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumTimeWithFixedSleep;
+import static org.apache.hadoop.io.retry.RetryPolicies.retryForeverWithFixedSleep;
 import static org.apache.hadoop.io.retry.RetryPolicies.exponentialBackoffRetry;
 import static org.junit.Assert.*;
 
@@ -110,7 +111,17 @@ public class TestRetryProxy {
     unreliable.failsOnceThenSucceeds();
     unreliable.failsTenTimesThenSucceeds();
   }
-  
+
+  @Test
+  public void testRetryForeverWithFixedSleep() throws UnreliableException {
+    UnreliableInterface unreliable = (UnreliableInterface) RetryProxy.create(
+        UnreliableInterface.class, unreliableImpl,
+        retryForeverWithFixedSleep(1, TimeUnit.MILLISECONDS));
+    unreliable.alwaysSucceeds();
+    unreliable.failsOnceThenSucceeds();
+    unreliable.failsTenTimesThenSucceeds();
+  }
+
   @Test
   public void testRetryUpToMaximumCountWithFixedSleep() throws UnreliableException {
     UnreliableInterface unreliable = (UnreliableInterface)