Fix FindBugs warnings in cds-access-client and enable enforcement

[controller.git] / opendaylight / md-sal / cds-access-client / src / main / java / org / opendaylight / controller / cluster / access / client / SequencedQueue.java

diff --git a/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/SequencedQueue.java b/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/SequencedQueue.java
index 5cf7873a4b95efadc64ba335dc3004aea9333bb4..596e353c981f3d21d193c66795753233c40bb6eb 100644 (file)
--- a/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/SequencedQueue.java
+++ b/opendaylight/md-sal/cds-access-client/src/main/java/org/opendaylight/controller/cluster/access/client/SequencedQueue.java
@@ -11,6 +11,7 @@ import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Ticker;
 import com.google.common.base.Verify;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import java.util.ArrayDeque;
 import java.util.Iterator;
 import java.util.Optional;
@@ -28,6 +29,8 @@ import org.slf4j.LoggerFactory;
 import scala.concurrent.duration.FiniteDuration;
 
 /*
+ * A queue that processes entries in sequence.
+ *
  * TODO: make this class and its users thread-safe. This will require some atomic state-keeping so that timeouts,
  *       retries and enqueues work as expected.
  */
@@ -118,7 +121,7 @@ final class SequencedQueue {
      * 2) The request has been enqueued and transmitted, but the caller needs to schedule a new timer
      * 3) The request has been enqueued, but the caller needs to request resolution of backend information and that
      *    process needs to complete before transmission occurs
-     *
+     * <p/>
      * These options are covered via returning an {@link Optional}. The caller needs to examine it and decode
      * the scenarios above according to the following rules:
      * - if is null, the first case applies
@@ -152,8 +155,14 @@ final class SequencedQueue {
         }
 
         // Ready to transmit
-        currentInflight.offer(e);
-        LOG.debug("Enqueued request {} to queue {}", request, this);
+
+        if (currentInflight.offer(e)) {
+            LOG.debug("Enqueued request {} to queue {}", request, this);
+        } else {
+            // This shouldn't happen since the queue has unlimited capacity but check anyway to avoid FindBugs warning
+            // about checking return value.
+            LOG.warn("Fail to enqueued request {} to queue {}", request, this);
+        }
 
         e.retransmit(backend, nextTxSequence(), now);
         if (expectingTimer == null) {
@@ -170,6 +179,8 @@ final class SequencedQueue {
      * - if a matching entry is not found, but it makes sense to keep looking at other queues, return null
      * - if a conflicting entry is encountered, indicating we should ignore this request, return an empty Optional
      */
+    @SuppressFBWarnings(value = "NP_OPTIONAL_RETURN_NULL",
+            justification = "Returning null Optional is documented in the API contract.")
     private static Optional<SequencedQueueEntry> findMatchingEntry(final Queue<SequencedQueueEntry> queue,
             final ResponseEnvelope<?> envelope) {
         // Try to find the request in a queue. Responses may legally come back in a different order, hence we need
@@ -271,7 +282,8 @@ final class SequencedQueue {
         transmitEntries(pending, toSend);
     }
 
-    Optional<FiniteDuration> setBackendInfo(final CompletionStage<? extends BackendInfo> proof, final BackendInfo backend) {
+    Optional<FiniteDuration> setBackendInfo(final CompletionStage<? extends BackendInfo> proof,
+            final BackendInfo backend) {
         Preconditions.checkNotNull(backend);
         if (!proof.equals(backendProof)) {
             LOG.debug("Ignoring resolution {} while waiting for {}", proof, this.backendProof);