BUG-5280: centralize ShardSnapshot operations

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/AbstractVersionedShardDataTreeSnapshot.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/AbstractVersionedShardDataTreeSnapshot.java
new file mode 100644 (file)
index 0000000..0d92eac
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/AbstractVersionedShardDataTreeSnapshot.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.datastore.persisted;
+
+import com.google.common.base.Verify;
+import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.Optional;
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * An internally-versioned {@link ShardDataTreeSnapshot}. This class is an intermediate implementation-private
+ * class.
+ *
+ * @author Robert Varga
+ */
+abstract class AbstractVersionedShardDataTreeSnapshot extends ShardDataTreeSnapshot {
+    private static final Logger LOG = LoggerFactory.getLogger(AbstractVersionedShardDataTreeSnapshot.class);
+
+    static ShardDataTreeSnapshot deserialize(final DataInputStream is) throws IOException {
+        final PayloadVersion version = PayloadVersion.readFrom(is);
+        switch (version) {
+            case BORON:
+                // Boron snapshots use Java Serialization
+                try (final ObjectInputStream ois = new ObjectInputStream(is)) {
+                    return (ShardDataTreeSnapshot) ois.readObject();
+                } catch (ClassNotFoundException e) {
+                    LOG.error("Failed to serialize data tree snapshot", e);
+                    throw new IOException("Snapshot failed to deserialize", e);
+                }
+            case TEST_FUTURE_VERSION:
+            case TEST_PAST_VERSION:
+                // These versions are never returned and this code is effectively dead
+                break;
+        }
+
+        // Not included as default in above switch to ensure we get warnings when new versions are added
+        throw new IOException("Encountered unhandled version" + version);
+    }
+
+    @Override
+    public final Optional<NormalizedNode<?, ?>> getRootNode() {
+        return Optional.of(Verify.verifyNotNull(rootNode(), "Snapshot %s returned non-present root node", getClass()));
+    }
+
+    /**
+     * Return the root node.
+     *
+     * @return The root node.
+     */
+    abstract @Nonnull NormalizedNode<?, ?> rootNode();
+
+    /**
+     * Return the snapshot payload version. Implementations of this method should return a constant.
+     *
+     * @return Snapshot payload version
+     */
+    abstract @Nonnull PayloadVersion version();
+
+    private void versionedSerialize(final DataOutputStream dos, final PayloadVersion version) throws IOException {
+        switch (version) {
+            case BORON:
+                // Boron snapshots use Java Serialization
+                try (ObjectOutputStream oos = new ObjectOutputStream(dos)) {
+                    oos.writeObject(this);
+                }
+                return;
+            case TEST_FUTURE_VERSION:
+            case TEST_PAST_VERSION:
+                break;
+
+        }
+
+        throw new IOException("Encountered unhandled version" + version);
+    }
+
+    @Override
+    public final byte[] serialize() throws IOException {
+        try (final ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
+            try (final DataOutputStream dos = new DataOutputStream(bos)) {
+                final PayloadVersion version = version();
+                version.writeTo(dos);
+                versionedSerialize(dos, version);
+            }
+
+            return bos.toByteArray();
+        }
+    }
+}