BUG-8219: optimize empty CompositeDataTreeCohort case

[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / CompositeDataTreeCohort.java

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/CompositeDataTreeCohort.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/CompositeDataTreeCohort.java
index 8115473a0565fb2c3865f4bc03e7216a8029a579..9d222bc2042c54413c77d2d424dac0274e38537e 100644 (file)
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/CompositeDataTreeCohort.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/CompositeDataTreeCohort.java
@@ -13,11 +13,11 @@ import akka.actor.Status.Failure;
 import akka.dispatch.ExecutionContexts;
 import akka.dispatch.Futures;
 import akka.dispatch.Recover;
-import akka.japi.Function;
 import akka.pattern.Patterns;
 import akka.util.Timeout;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import java.util.Collection;
 import java.util.Iterator;
@@ -91,7 +91,6 @@ class CompositeDataTreeCohort {
         }
     };
 
-
     private final DataTreeCohortActorRegistry registry;
     private final TransactionIdentifier txId;
     private final SchemaContext schema;
@@ -109,21 +108,26 @@ class CompositeDataTreeCohort {
 
     void canCommit(final DataTreeCandidate tip) throws ExecutionException, TimeoutException {
         Collection<CanCommit> messages = registry.createCanCommitMessages(txId, tip, schema);
-        // FIXME: Optimize empty collection list with pre-created futures, containing success.
-        Future<Iterable<Object>> canCommitsFuture =
-                Futures.traverse(messages, new Function<CanCommit, Future<Object>>() {
-                    @Override
-                    public Future<Object> apply(final CanCommit input) {
-                        return Patterns.ask(input.getCohort(), input, timeout).recover(EXCEPTION_TO_MESSAGE,
-                                ExecutionContexts.global());
-                    }
-                }, ExecutionContexts.global());
+        if (messages.isEmpty()) {
+            successfulFromPrevious = ImmutableList.of();
+            changeStateFrom(State.IDLE, State.CAN_COMMIT_SUCCESSFUL);
+            return;
+        }
+
+        Future<Iterable<Object>> canCommitsFuture = Futures.traverse(messages,
+            input -> Patterns.ask(input.getCohort(), input, timeout).recover(EXCEPTION_TO_MESSAGE,
+                ExecutionContexts.global()), ExecutionContexts.global());
         changeStateFrom(State.IDLE, State.CAN_COMMIT_SENT);
         processResponses(canCommitsFuture, State.CAN_COMMIT_SENT, State.CAN_COMMIT_SUCCESSFUL);
     }
 
     void preCommit() throws ExecutionException, TimeoutException {
         Preconditions.checkState(successfulFromPrevious != null);
+        if (isEmpty()) {
+            changeStateFrom(State.CAN_COMMIT_SUCCESSFUL, State.PRE_COMMIT_SUCCESSFUL);
+            return;
+        }
+
         Future<Iterable<Object>> preCommitFutures = sendMesageToSuccessful(new DataTreeCohortActor.PreCommit(txId));
         changeStateFrom(State.CAN_COMMIT_SUCCESSFUL, State.PRE_COMMIT_SENT);
         processResponses(preCommitFutures, State.PRE_COMMIT_SENT, State.PRE_COMMIT_SUCCESSFUL);
@@ -131,6 +135,11 @@ class CompositeDataTreeCohort {
 
     void commit() throws ExecutionException, TimeoutException {
         Preconditions.checkState(successfulFromPrevious != null);
+        if (isEmpty()) {
+            changeStateFrom(State.PRE_COMMIT_SUCCESSFUL, State.COMMITED);
+            return;
+        }
+
         Future<Iterable<Object>> commitsFuture = sendMesageToSuccessful(new DataTreeCohortActor.Commit(txId));
         changeStateFrom(State.PRE_COMMIT_SUCCESSFUL, State.COMMIT_SENT);
         processResponses(commitsFuture, State.COMMIT_SENT, State.COMMITED);
@@ -144,19 +153,17 @@ class CompositeDataTreeCohort {
         return Optional.empty();
     }
 
-    private Future<Iterable<Object>> sendMesageToSuccessful(final Object message) {
-        return Futures.traverse(successfulFromPrevious, new Function<DataTreeCohortActor.Success, Future<Object>>() {
-
-            @Override
-            public Future<Object> apply(final DataTreeCohortActor.Success cohortResponse) throws Exception {
-                return Patterns.ask(cohortResponse.getCohort(), message, timeout);
-            }
+    private boolean isEmpty() {
+        return successfulFromPrevious instanceof Collection && ((Collection<?>) successfulFromPrevious).isEmpty();
+    }
 
-        }, ExecutionContexts.global());
+    private Future<Iterable<Object>> sendMesageToSuccessful(final Object message) {
+        return Futures.traverse(successfulFromPrevious, cohortResponse -> Patterns.ask(cohortResponse.getCohort(),
+            message, timeout), ExecutionContexts.global());
     }
 
-    private void processResponses(final Future<Iterable<Object>> resultsFuture, final State currentState, final State afterState)
-            throws TimeoutException, ExecutionException {
+    private void processResponses(final Future<Iterable<Object>> resultsFuture, final State currentState,
+            final State afterState) throws TimeoutException, ExecutionException {
         final Iterable<Object> results;
         try {
             results = Await.result(resultsFuture, timeout.duration());
@@ -182,7 +189,7 @@ class CompositeDataTreeCohort {
         changeStateFrom(currentState, afterState);
     }
 
-    void changeStateFrom(final State expected, final State followup) {
+    private void changeStateFrom(final State expected, final State followup) {
         Preconditions.checkState(state == expected);
         state = followup;
     }