Make Raft messages serializable

[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / protobuff / client / messages / Payload.java

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/protobuff/client/messages/Payload.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/protobuff/client/messages/Payload.java
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+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/protobuff/client/messages/Payload.java
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+/*
+ * Copyright (c) 2014 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.raft.protobuff.client.messages;
+
+
+import com.google.protobuf.GeneratedMessage;
+import org.opendaylight.controller.cluster.raft.protobuff.messages.AppendEntriesMessages;
+
+import java.util.Map;
+
+/**
+ * An instance of a Payload class is meant to be used as the Payload for
+ * AppendEntries.
+ * <p>
+ *
+ * When an actor which is derived from RaftActor attempts to persistData it
+ * must pass an instance of the Payload class. Similarly when state needs to
+ * be applied to the derived RaftActor it will be passed an instance of the
+ * Payload class.
+ * <p>
+ *
+ * To define your own payload do the following,
+ * <ol>
+ *     <li>Create your own protocol buffer message which extends the AppendEntries Payload</li>
+ *     <li>Extend this Payload class</li>
+ *     <li>Implement encode</li>
+ *     <li>Implement decode</li>
+ * </ol>
+ *
+ * Your own protocol buffer message can be create like so, <br/>
+ * <pre>
+ * {@code
+ *
+ * import "AppendEntriesMessages.proto";
+ *
+ * package org.opendaylight.controller.cluster.raft;
+ *
+ * option java_package = "org.opendaylight.controller.cluster.raft.protobuff.messages";
+ * option java_outer_classname = "MockPayloadMessages";
+ *
+ * extend AppendEntries.ReplicatedLogEntry.Payload {
+ *      optional string value = 2;
+ * }
+ * }
+ * </pre>
+ *
+ */
+public abstract class Payload {
+    private String clientPayloadClassName;
+
+    public String getClientPayloadClassName() {
+        return this.getClass().getName();
+    }
+
+    public void setClientPayloadClassName(String clientPayloadClassName) {
+        this.clientPayloadClassName = clientPayloadClassName;
+    }
+
+    /**
+     * Encode the payload data as a protocol buffer extension.
+     * <p>
+     * TODO: Add more meat in here
+     * @param <T>
+     * @return Map of <GeneratedMessage.GeneratedExtension, T>
+     */
+    public abstract <T extends Object> Map<GeneratedMessage.GeneratedExtension, T> encode();
+
+    /**
+     * Decode the protocol buffer payload into a specific Payload as defined
+     * by the class extending RaftActor
+     *
+     * @param payload The payload in protocol buffer format
+     * @return
+     */
+    public abstract Payload decode(
+        AppendEntriesMessages.AppendEntries.ReplicatedLogEntry.Payload payload);
+
+
+
+}