From f6c973a08db45c7b00ac36d87b016ef63e65923c Mon Sep 17 00:00:00 2001
From: Madan Jampani <madan.jampani@gmail.com>
Date: Sat, 30 Jan 2016 22:20:48 -0800
Subject: [PATCH] DefaultConsistentMap to automatically retry compute* calls
 failing due to ConcurrentModification

Change-Id: If59e432e423d323282eb8fe7b1b438899154aae9
---
 .../primitives/impl/DefaultConsistentMap.java | 24 ++++++++++++-------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultConsistentMap.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultConsistentMap.java
index e09b6249fc..f804611bc2 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultConsistentMap.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/DefaultConsistentMap.java
@@ -19,6 +19,7 @@ package org.onosproject.store.primitives.impl;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -28,14 +29,18 @@ import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
+import org.onlab.util.Tools;
 import org.onosproject.store.primitives.ConsistentMapBackedJavaMap;
 import org.onosproject.store.service.AsyncConsistentMap;
 import org.onosproject.store.service.ConsistentMap;
 import org.onosproject.store.service.ConsistentMapException;
+import org.onosproject.store.service.ConsistentMapException.ConcurrentModification;
 import org.onosproject.store.service.MapEventListener;
 import org.onosproject.store.service.Synchronous;
 import org.onosproject.store.service.Versioned;
 
+import com.google.common.base.Throwables;
+
 /**
  * Default implementation of {@code ConsistentMap}.
  *
@@ -45,6 +50,7 @@ import org.onosproject.store.service.Versioned;
 public class DefaultConsistentMap<K, V> extends Synchronous<AsyncConsistentMap<K, V>> implements ConsistentMap<K, V> {
 
     private static final int OPERATION_TIMEOUT_MILLIS = 5000;
+    private static final int MAX_DELAY_BETWEEN_RETY_MILLS = 50;
 
     private final AsyncConsistentMap<K, V> asyncMap;
     private Map<K, V> javaMap;
@@ -82,26 +88,29 @@ public class DefaultConsistentMap<K, V> extends Synchronous<AsyncConsistentMap<K
     @Override
     public Versioned<V> computeIfAbsent(K key,
             Function<? super K, ? extends V> mappingFunction) {
-        return complete(asyncMap.computeIfAbsent(key, mappingFunction));
+        return computeIf(key, Objects::isNull, (k, v) -> mappingFunction.apply(k));
     }
 
     @Override
     public Versioned<V> computeIfPresent(K key,
             BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
-        return complete(asyncMap.computeIfPresent(key, remappingFunction));
+        return computeIf(key, Objects::nonNull, remappingFunction);
     }
 
     @Override
     public Versioned<V> compute(K key,
             BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
-        return complete(asyncMap.compute(key, remappingFunction));
+        return computeIf(key, v -> true, remappingFunction);
     }
 
     @Override
     public Versioned<V> computeIf(K key,
             Predicate<? super V> condition,
             BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
-        return complete(asyncMap.computeIf(key, condition, remappingFunction));
+        return Tools.retryable(() -> complete(asyncMap.computeIf(key, condition, remappingFunction)),
+                               ConcurrentModification.class,
+                               Integer.MAX_VALUE,
+                               MAX_DELAY_BETWEEN_RETY_MILLS).get();
     }
 
     @Override
@@ -203,11 +212,8 @@ public class DefaultConsistentMap<K, V> extends Synchronous<AsyncConsistentMap<K
         } catch (TimeoutException e) {
             throw new ConsistentMapException.Timeout();
         } catch (ExecutionException e) {
-            if (e.getCause() instanceof ConsistentMapException) {
-                throw (ConsistentMapException) e.getCause();
-            } else {
-                throw new ConsistentMapException(e.getCause());
-            }
+            Throwables.propagateIfPossible(e.getCause());
+            throw new ConsistentMapException(e.getCause());
         }
     }
 }
\ No newline at end of file