/*
 * Copyright (c) 2010-2016. Axon Framework
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.axonframework.jgroups.commandhandling;

import org.axonframework.commandhandling.CommandMessage;
import org.axonframework.commandhandling.distributed.DispatchMessage;
import org.axonframework.serialization.Serializer;
import org.jgroups.util.Streamable;

import java.io.*;

/**
 * JGroups message that contains a CommandMessage that needs to be dispatched on a remote command bus segment. This
 * class implements the {@link Streamable} interface for faster JGroups-specific serialization, but also supports
 * Java serialization by implementing the {@link Externalizable} interface.
 *
 * @author Allard Buijze
 * @since 2.0
 */
public class JGroupsDispatchMessage extends DispatchMessage implements Streamable, Externalizable {

    private static final long serialVersionUID = -8792911964758889674L;

    /**
     * Default constructor required by the {@link Streamable} and {@link Externalizable} interfaces. Do not use
     * directly.
     */
    @SuppressWarnings("UnusedDeclaration")
    public JGroupsDispatchMessage() {
    }

    /**
     * Initialize a JGroupsDispatchMessage for the given {@code commandMessage}, to be serialized using given
     * {@code serializer}. {@code expectReply} indicates whether the sender will be expecting a reply.
     *
     * @param commandMessage The message to send to the remote segment
     * @param serializer     The serialize to serialize the message payload and metadata with
     * @param expectReply    whether or not the sender is waiting for a reply.
     */
    public JGroupsDispatchMessage(CommandMessage<?> commandMessage, Serializer serializer, boolean expectReply) {
        super(commandMessage, serializer, expectReply);
    }

    @Override
    public void writeTo(DataOutput out) throws IOException {
        out.writeUTF(commandName);
        out.writeUTF(commandIdentifier);
        out.writeBoolean(expectReply);
        out.writeUTF(payloadType);
        out.writeUTF(payloadRevision == null ? "_null" : payloadRevision);
        out.writeInt(serializedPayload.length);
        out.write(serializedPayload);
        out.writeInt(serializedMetaData.length);
        out.write(serializedMetaData);
    }

    @Override
    public void readFrom(DataInput in) throws IOException {
        commandName = in.readUTF();
        commandIdentifier = in.readUTF();
        expectReply = in.readBoolean();
        payloadType = in.readUTF();
        payloadRevision = in.readUTF();
        if ("_null".equals(payloadRevision)) {
            payloadRevision = null;
        }
        serializedPayload = new byte[in.readInt()];
        in.readFully(serializedPayload);
        serializedMetaData = new byte[in.readInt()];
        in.readFully(serializedMetaData);
    }

    @Override
    public void writeExternal(ObjectOutput out) throws IOException {
        writeTo(out);
    }

    @Override
    public void readExternal(ObjectInput in) throws IOException {
        readFrom(in);
    }

}