BUG-5930: introduce PayloadVersion

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/PayloadVersion.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/PayloadVersion.java
new file mode 100644 (file)
index 0000000..051a375
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/persisted/PayloadVersion.java
@@ -0,0 +1,126 @@
+/*
+ * 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.annotations.Beta;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import javax.annotation.Nonnull;
+import org.opendaylight.yangtools.concepts.WritableObject;
+
+/**
+ * Enumeration of all ABI versions supported by this implementation of persistence. An ABI version has to be bumped
+ * whenever:
+ * - a new event is defined
+ * - serialization format is changed
+ *
+ * This version effectively defines the protocol version between actors participating on a particular shard. A shard
+ * participant instance should oppose RAFT candidates which produce persistence of an unsupported version. If a follower
+ * encounters an unsupported version it must not become fully-operational, as it does not have an accurate view
+ * of shard state.
+ *
+ * @author Robert Varga
+ */
+@Beta
+public enum PayloadVersion implements WritableObject {
+    // NOTE: enumeration values need to be sorted in asceding order of their version to keep Comparable working
+
+    /**
+     * Version which is older than any other version. This version exists purely for testing purposes.
+     */
+    @VisibleForTesting
+    TEST_PAST_VERSION(0),
+
+    /**
+     * Initial ABI version, as shipped with Boron Simultaneous release.
+     */
+    // We seed the initial version to be the same as DataStoreVersions.BORON-VERSION for compatibility reasons.
+    BORON(5),
+
+    /**
+     * Version which is newer than any other version. This version exists purely for testing purposes.
+     */
+    @VisibleForTesting
+    TEST_FUTURE_VERSION(65535);
+
+    private final short value;
+
+    PayloadVersion(final int intVersion) {
+        Preconditions.checkArgument(intVersion >= 0 && intVersion <= 65535);
+        value = (short) intVersion;
+    }
+
+    /**
+     * Return the unsigned short integer identifying this version.
+     *
+     * @return Unsigned short integer identifying this version
+     */
+    public short shortValue() {
+        return value;
+    }
+
+    /**
+     * Return the codebase-native persistence version. This version is the default version allocated to messages
+     * at runtime. Conversion to previous versions may incur additional overhead (such as object allocation).
+     *
+     * @return Current {@link PayloadVersion}
+     */
+    public static @Nonnull PayloadVersion current() {
+        return BORON;
+    }
+
+    /**
+     * Return the {@link PayloadVersion} corresponding to an unsigned short integer. This method is provided for callers
+     * which provide their own recovery strategy in case of version incompatibility.
+     *
+     * @param s Short integer as returned from {@link #shortValue()}
+     * @return {@link PayloadVersion}
+     * @throws FutureVersionException if the specified integer identifies a future version
+     * @throws PastVersionException if the specified integer identifies a past version which is no longer supported
+     */
+    public static @Nonnull PayloadVersion valueOf(final short s) throws FutureVersionException, PastVersionException {
+        switch (Short.toUnsignedInt(s)) {
+            case 0:
+            case 1:
+            case 2:
+            case 3:
+            case 4:
+                throw new PastVersionException(s, BORON);
+            case 5:
+                return BORON;
+            default:
+                throw new FutureVersionException(s, BORON);
+        }
+    }
+
+    @Override
+    public void writeTo(final DataOutput out) throws IOException {
+        out.writeShort(value);
+    }
+
+    /**
+     * Read an {@link PayloadVersion} from a {@link DataInput}. This method is provided for callers which do not have
+     * a recovery strategy for dealing with unsupported versions.
+     *
+     * @param in Input from which to read
+     * @return An {@link PayloadVersion}
+     * @throws IOException If read fails or an unsupported version is encountered
+     */
+    public static @Nonnull PayloadVersion readFrom(final @Nonnull DataInput in) throws IOException {
+        final short s = in.readShort();
+        try {
+            return valueOf(s);
+        } catch (FutureVersionException | PastVersionException e) {
+            throw new IOException("Unsupported version", e);
+        }
+    }
+
+}