X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fcds-access-client%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Faccess%2Fclient%2FBackendInfoResolver.java;h=5c5cda5bae0b8f7eb2e4bb02bd827e47c234c07b;hp=cb648091203ba170014e084c30f01f93bf3f2b56;hb=HEAD;hpb=b0067e0a4bfa955f15c6259e019f954687264eff

diff --git a/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/BackendInfoResolver.java b/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/BackendInfoResolver.java
index cb64809120..5c5cda5bae 100644
--- a/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/BackendInfoResolver.java
+++ b/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/BackendInfoResolver.java
@@ -8,18 +8,10 @@
 package org.opendaylight.controller.cluster.access.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;
-import org.slf4j.LoggerFactory;
+import java.util.function.Consumer;
+import org.eclipse.jdt.annotation.NonNull;
+import org.opendaylight.yangtools.concepts.Registration;
 
 /**
  * Caching resolver which resolves a cookie to a leader {@link ActorRef}. This class needs to be specialized by the
@@ -27,71 +19,47 @@ import org.slf4j.LoggerFactory;
  * by either the client actor (when a message timeout is detected) and by the specific frontend (on explicit
  * invalidation or when updated information becomes available).
  *
+ * <p>
+ * If the completion stage returned by this interface's methods fails with a
+ * {@link org.opendaylight.controller.cluster.access.concepts.RequestException}, it will be forwarded to all
+ * outstanding requests towards the leader. If it fails with a {@link java.util.concurrent.TimeoutException},
+ * resolution process will be retried. If it fails with any other cause, it will we wrapped as a
+ * {@link org.opendaylight.controller.cluster.access.concepts.RuntimeRequestException} wrapping that cause.
+ *
  * @author Robert Varga
  */
-@ThreadSafe
-public abstract class BackendInfoResolver<T extends BackendInfo> {
-    private static final Logger LOG = LoggerFactory.getLogger(BackendInfoResolver.class);
-    private final ConcurrentMap<Long, CompletableFuture<T>> backends = new ConcurrentHashMap<>();
-
+public abstract class BackendInfoResolver<T extends BackendInfo> implements AutoCloseable {
     /**
-     * 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.
+     * Request resolution of a particular backend identified by a cookie. This request can be satisfied from the cache.
      *
      * @param cookie Backend cookie
-     * @return Backend information, if available
+     * @return A {@link CompletionStage} resulting in information about the backend
      */
-    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();
-    }
+    public abstract @NonNull CompletionStage<? extends T> getBackendInfo(@NonNull Long cookie);
 
     /**
-     * Invalidate a particular instance of {@link BackendInfo}, typically as a response to a request timing out. If
-     * the provided information is not the one currently cached this method does nothing.
+     * Request re-resolution of a particular backend identified by a cookie, indicating a particular information as
+     * being stale. If the implementation's cache holds the stale information, it should be purged.
      *
      * @param cookie Backend cookie
-     * @param info Previous information to be invalidated
+     * @param staleInfo Stale backend information
+     * @return A {@link CompletionStage} resulting in information about the backend
      */
-    public final void invalidateBackend(final long cookie, final @Nonnull CompletionStage<? extends BackendInfo> info) {
-        if (backends.remove(cookie, Preconditions.checkNotNull(info))) {
-            LOG.trace("Invalidated cache %s -> %s", Long.toUnsignedString(cookie), info);
-            invalidateBackendInfo(info);
-        }
-    }
+    public abstract @NonNull CompletionStage<? extends T> refreshBackendInfo(@NonNull Long cookie,
+            @NonNull T staleInfo);
 
     /**
-     * Request new resolution of a particular backend identified by a cookie. This method is invoked when a client
-     * requests information which is not currently cached.
+     * Registers a callback to be notified when BackendInfo that may have been previously obtained is now stale and
+     * should be refreshed.
      *
-     * @param cookie Backend cookie
-     * @return A {@link CompletableFuture} resulting in information about the backend
+     * @param callback the callback that takes the backend cookie whose BackendInfo is now stale.
+     * @return a Registration
      */
-    protected abstract @Nonnull CompletableFuture<T> resolveBackendInfo(final @Nonnull Long cookie);
+    public abstract @NonNull Registration notifyWhenBackendInfoIsStale(Consumer<Long> callback);
 
-    /**
-     * Invalidate previously-resolved shard information. This method is invoked when a timeout is detected
-     * and the information may need to be refreshed.
-     *
-     * @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);
-    }
+    public abstract @NonNull String resolveCookieName(Long cookie);
 
-    private CompletableFuture<T> lookupBackend(final Long cookie) {
-        return backends.computeIfAbsent(Preconditions.checkNotNull(cookie), this::resolveBackendInfo);
+    @Override
+    public void close() {
     }
 }