Define efficient serialization proxies

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/ShardManagerSnapshot.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/ShardManagerSnapshot.java
index 03ffa9af793a2778c07fb119a4360e1b6819bb3d..2e0320bbcd7785d3cdb5546d3098280cce9180f0 100644 (file)
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/ShardManagerSnapshot.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/ShardManagerSnapshot.java
@@ -7,6 +7,9 @@
  */
 package org.opendaylight.controller.cluster.datastore.persisted;
 
  */
 package org.opendaylight.controller.cluster.datastore.persisted;
 

+import static com.google.common.base.Verify.verifyNotNull;
+import static java.util.Objects.requireNonNull;
+

 import com.google.common.collect.ImmutableList;
 import java.io.Externalizable;
 import java.io.IOException;
 import com.google.common.collect.ImmutableList;
 import java.io.Externalizable;
 import java.io.IOException;


@@ -23,7 +26,50 @@ import org.eclipse.jdt.annotation.NonNull;
  * @author Thomas Pantelis
  */
 public final class ShardManagerSnapshot implements Serializable {
  * @author Thomas Pantelis
  */
 public final class ShardManagerSnapshot implements Serializable {

-    private static final class Proxy implements Externalizable {
+    interface SerializedForm extends Externalizable {
+        /**
+         * Return the serial form of this object contents, corresponding to {@link ShardManagerSnapshot#shardList}.
+         *
+         * @return List of shards names.
+         */
+        List<String> shardNames();
+
+        /**
+         * Resolve this proxy to an actual {@link ShardManagerSnapshot}. Implementations can rely on the object to be
+         * set via {@link #resolveTo(ShardManagerSnapshot)}.
+         *
+         * @return A snapshot
+         */
+        Object readResolve();
+
+        /**
+         * Set this proxy to return {@code snapshot} on next {@link #readResolve()}.
+         *
+         * @param newSnapshot Snapshot to set
+         */
+        void resolveTo(@NonNull ShardManagerSnapshot newSnapshot);
+
+        @Override
+        default void readExternal(final ObjectInput in) throws IOException, ClassNotFoundException {
+            final int size = in.readInt();
+            final var shardList = new ArrayList<String>(size);
+            for (int i = 0; i < size; i++) {
+                shardList.add((String) in.readObject());
+            }
+            resolveTo(new ShardManagerSnapshot(shardList));
+        }
+
+        @Override
+        default void writeExternal(final ObjectOutput out) throws IOException {
+            final var shardList = shardNames();
+            out.writeInt(shardList.size());
+            for (var shardName : shardList) {
+                out.writeObject(shardName);
+            }
+        }
+    }
+
+    private static final class Proxy implements SerializedForm {

         private static final long serialVersionUID = 1L;
 
         private ShardManagerSnapshot snapshot;
         private static final long serialVersionUID = 1L;
 
         private ShardManagerSnapshot snapshot;


@@ -40,26 +86,18 @@ public final class ShardManagerSnapshot implements Serializable {
         }
 
         @Override
         }
 
         @Override

-        public void writeExternal(final ObjectOutput out) throws IOException {
-            out.writeInt(snapshot.shardList.size());
-            for (String shard: snapshot.shardList) {
-                out.writeObject(shard);
-            }
+        public List<String> shardNames() {
+            return snapshot.getShardList();

         }
 
         @Override
         }
 
         @Override

-        public void readExternal(final ObjectInput in) throws IOException, ClassNotFoundException {
-            int size = in.readInt();
-            List<String> localShardList = new ArrayList<>(size);
-            for (int i = 0; i < size; i++) {
-                localShardList.add((String) in.readObject());
-            }
-
-            snapshot = new ShardManagerSnapshot(localShardList);
+        public void resolveTo(final ShardManagerSnapshot newSnapshot) {
+            snapshot = requireNonNull(newSnapshot);

         }
 
         }
 

-        private Object readResolve() {
-            return snapshot;
+        @Override
+        public Object readResolve() {
+            return verifyNotNull(snapshot);

         }
     }
 
         }
     }