Add support for reusable streaming

With the actual implementations working on top of
NormalizedNodeStreamWriter, we gained the ability to flexibly
receive stream events.

This patch takes advantage of that flexibility by allowing
a ReusableImmutableNormalizedNodeStreamWriter to be the receiver
of the events -- thus allowing parts of the state involved in
building a NormalizedNode tree to be reused -- lowering GC
pressure.

A number of call sites, which can safely reuse such state are
converted to use the newly-introduced facility.

Change-Id: Iaf1b3ab2b2996e7004c036fc93a80a8ca8792314
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/ForwardingNormalizedNodeDataInput.java b/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/ForwardingNormalizedNodeDataInput.java
index 1c160698a4b7dd7dff642ef7d31f4f34e1779dd1..a1a0d69426f31bcbf4aee4e4fc3ca244b93f65ff 100644 (file)
--- a/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/ForwardingNormalizedNodeDataInput.java
+++ b/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/ForwardingNormalizedNodeDataInput.java
@@ -14,6 +14,7 @@ import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.PathArgument;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
+import org.opendaylight.yangtools.yang.data.impl.schema.ReusableImmutableNormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
 
 abstract class ForwardingNormalizedNodeDataInput extends ForwardingDataInput implements NormalizedNodeDataInput {
@@ -31,6 +32,12 @@ abstract class ForwardingNormalizedNodeDataInput extends ForwardingDataInput imp
         return delegate().readNormalizedNode();
     }
 
+    @Override
+    public final NormalizedNode<?, ?> readNormalizedNode(final ReusableImmutableNormalizedNodeStreamWriter writer)
+            throws IOException {
+        return delegate().readNormalizedNode(writer);
+    }
+
     @Override
     public final YangInstanceIdentifier readYangInstanceIdentifier() throws IOException {
         return delegate().readYangInstanceIdentifier();

diff --git a/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/NormalizedNodeDataInput.java b/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/NormalizedNodeDataInput.java
index 9dda8bf6e47f5c1664b1060d7cc085196f6a64fa..57d41d58354a916e401ae1e2424b1db167386ddb 100644 (file)
--- a/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/NormalizedNodeDataInput.java
+++ b/java/org/opendaylight/controller/cluster/datastore/node/utils/stream/NormalizedNodeDataInput.java
@@ -19,6 +19,7 @@ import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.data.impl.schema.NormalizedNodeResult;
+import org.opendaylight.yangtools.yang.data.impl.schema.ReusableImmutableNormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.model.api.SchemaPath;
 
 /**
@@ -52,6 +53,24 @@ public interface NormalizedNodeDataInput extends DataInput {
         return result.getResult();
     }
 
+    /**
+     * Read a normalized node from the reader, using specified writer to construct the result.
+     *
+     * @param writer Reusable writer to
+     * @return Next node from the stream, or null if end of stream has been reached.
+     * @throws IOException if an error occurs
+     * @throws IllegalStateException if the dictionary has been detached
+     */
+    default NormalizedNode<?, ?> readNormalizedNode(final ReusableImmutableNormalizedNodeStreamWriter writer)
+            throws IOException {
+        try {
+            streamNormalizedNode(writer);
+            return writer.getResult();
+        } finally {
+            writer.reset();
+        }
+    }
+
     YangInstanceIdentifier readYangInstanceIdentifier() throws IOException;
 
     @NonNull QName readQName() throws IOException;