BUG-5280: implement transaction dispatch

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/actors/client/BackendInfoResolver.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/actors/client/BackendInfoResolver.java
index 2868998dac9c94434abeb253c8ca7c8c443ba3ec..b2fbc6b33693c7b7bb629271f9383dfb1d8bd4fa 100644 (file)
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/actors/client/BackendInfoResolver.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/actors/client/BackendInfoResolver.java
@@ -9,9 +9,13 @@ package org.opendaylight.controller.cluster.datastore.actors.client;
 
 import akka.actor.ActorRef;
 import com.google.common.base.Preconditions;
+import java.util.Optional;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.ThreadSafe;
 import org.slf4j.Logger;
@@ -28,12 +32,26 @@ import org.slf4j.LoggerFactory;
 @ThreadSafe
 public abstract class BackendInfoResolver<T extends BackendInfo> {
     private static final Logger LOG = LoggerFactory.getLogger(BackendInfoResolver.class);
-    private final ConcurrentMap<Long, CompletionStage<T>> backends = new ConcurrentHashMap<>();
+    private final ConcurrentMap<Long, CompletableFuture<T>> backends = new ConcurrentHashMap<>();
 
-    // This is what the client needs to start processing. For as long as we do not have this, we should not complete
-    // this stage until we have this information
-    public final CompletionStage<? extends T> getBackendInfo(final long cookie) {
-        return backends.computeIfAbsent(cookie, this::resolveBackendInfo);
+    /**
+     * Return the currently-resolved backend information, if available. This method is guaranteed not to block, but will
+     * initiate resolution of the information if there is none.
+     *
+     * @param cookie Backend cookie
+     * @return Backend information, if available
+     */
+    public final Optional<T> getFutureBackendInfo(final Long cookie) {
+        final Future<T> f = lookupBackend(cookie);
+        if (f.isDone()) {
+            try {
+                return Optional.of(f.get());
+            } catch (InterruptedException | ExecutionException e) {
+                LOG.debug("Resolution of {} failed", f, e);
+            }
+        }
+
+        return Optional.empty();
     }
 
     /**
@@ -55,9 +73,9 @@ public abstract class BackendInfoResolver<T extends BackendInfo> {
      * requests information which is not currently cached.
      *
      * @param cookie Backend cookie
-     * @return A {@link CompletionStage} resulting in information about the backend
+     * @return A {@link CompletableFuture} resulting in information about the backend
      */
-    protected abstract @Nonnull CompletionStage<T> resolveBackendInfo(final @Nonnull Long cookie);
+    protected abstract @Nonnull CompletableFuture<T> resolveBackendInfo(final @Nonnull Long cookie);
 
     /**
      * Invalidate previously-resolved shard information. This method is invoked when a timeout is detected
@@ -66,4 +84,14 @@ public abstract class BackendInfoResolver<T extends BackendInfo> {
      * @param info Previous promise of backend information
      */
     protected abstract void invalidateBackendInfo(@Nonnull CompletionStage<? extends BackendInfo> info);
+
+    // This is what the client needs to start processing. For as long as we do not have this, we should not complete
+    // this stage until we have this information
+    final CompletionStage<? extends T> getBackendInfo(final Long cookie) {
+        return lookupBackend(cookie);
+    }
+
+    private CompletableFuture<T> lookupBackend(final Long cookie) {
+        return backends.computeIfAbsent(Preconditions.checkNotNull(cookie), this::resolveBackendInfo);
+    }
 }