ISPN-5963 Avoid allocating CompletableFuture instances for empty maps

infinispan · Nov 23, 2015 · 8e58677 · 8e58677
1 parent 233af68
commit 8e58677
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Showing 3 changed files with 15 additions and 4 deletions.
diff --git a/core/src/main/java/org/infinispan/remoting/rpc/RpcManagerImpl.java b/core/src/main/java/org/infinispan/remoting/rpc/RpcManagerImpl.java
@@ -128,7 +128,7 @@ public CompletableFuture<Map<Address, Response>> invokeRemotelyAsync(Collection<
             log.tracef("Using replication queue for command [%s]", rpc);
          }
          replicationQueue.add(rpc);
-         return CompletableFuture.completedFuture(InfinispanCollections.emptyMap());
+         return CompletableFutures.returnEmptyMap();
       }
       if (!configuration.clustering().cacheMode().isClustered())
          throw new IllegalStateException("Trying to invoke a remote command but the cache is not clustered");

diff --git a/core/src/main/java/org/infinispan/remoting/transport/jgroups/JGroupsTransport.java b/core/src/main/java/org/infinispan/remoting/transport/jgroups/JGroupsTransport.java
@@ -27,6 +27,7 @@
 import org.infinispan.remoting.transport.AbstractTransport;
 import org.infinispan.remoting.transport.Address;
 import org.infinispan.remoting.transport.BackupResponse;
+import org.infinispan.util.concurrent.CompletableFutures;
 import org.infinispan.util.TimeService;
 import org.infinispan.util.concurrent.TimeoutException;
 import org.infinispan.util.logging.Log;
@@ -560,7 +561,7 @@ public CompletableFuture<Map<Address, Response>> invokeRemotelyAsync(Collection<
                if (singleRecipient) singleJGAddress = toJGroupsAddress(others.get(0));
             }
             if (skipRpc) {
-               return CompletableFuture.completedFuture(InfinispanCollections.emptyMap());
+               return CompletableFutures.returnEmptyMap();
             }
 
             if (singleRecipient) {
@@ -573,12 +574,12 @@ public CompletableFuture<Map<Address, Response>> invokeRemotelyAsync(Collection<
 
             }
          } else {
-            return CompletableFuture.completedFuture(InfinispanCollections.emptyMap());
+            return CompletableFutures.returnEmptyMap();
          }
       }
 
       if (mode.isAsynchronous()) {
-         return CompletableFuture.completedFuture(InfinispanCollections.emptyMap());
+         return CompletableFutures.returnEmptyMap();
       }
 
       if (singleResponseFuture != null) {

diff --git a/core/src/main/java/org/infinispan/util/concurrent/CompletableFutures.java b/core/src/main/java/org/infinispan/util/concurrent/CompletableFutures.java
@@ -1,5 +1,6 @@
 package org.infinispan.util.concurrent;
 
+import org.infinispan.commons.util.InfinispanCollections;
 import org.infinispan.commons.util.concurrent.NotifyingNotifiableFuture;
 
 import java.util.concurrent.CompletableFuture;
@@ -8,13 +9,22 @@
 
 import static java.util.Objects.requireNonNull;
 
+import java.util.Map;
+
 /**
  * Utility methods connecting {@link CompletableFuture} futures and our {@link NotifyingNotifiableFuture} futures.
  *
  * @author Dan Berindei
  * @since 8.0
  */
 public class CompletableFutures {
+
+   private static final CompletableFuture completedEmptyMapFuture = CompletableFuture.completedFuture(InfinispanCollections.emptyMap());
+
+   public static <K,V> CompletableFuture<Map<K, V>> returnEmptyMap() {
+      return (CompletableFuture<Map<K, V>>) completedEmptyMapFuture;
+   }
+
    public static <T> void connect(NotifyingNotifiableFuture<T> sink, CompletableFuture<T> source) {
       CompletableFuture<T> compoundSource = source.whenComplete((value, throwable) -> {
          if (throwable == null) {