/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.reef.task;


import org.apache.reef.annotations.Provided;
import org.apache.reef.annotations.audience.EvaluatorSide;
import org.apache.reef.annotations.audience.Public;
import org.apache.reef.io.Message;

/**
 * A message sent from a Task to a Driver.
 */
@EvaluatorSide
@Public
@Provided
public final class TaskMessage implements Message {

  private final String messageSourceID;
  private final byte[] theBytes;

  private TaskMessage(final String messageSourceID, final byte[] theBytes) {
    this.messageSourceID = messageSourceID;
    this.theBytes = theBytes;
  }

  /**
   * @param messageSourceID The message's sourceID. This will be accessible in the Driver for routing.
   * @param theBytes        The actual content of the message, serialized into a byte[]
   * @return a new TaskMessage with the given content.
   */
  public static TaskMessage from(final String messageSourceID, final byte[] theBytes) {
    assert theBytes != null && messageSourceID != null;
    return new TaskMessage(messageSourceID, theBytes);
  }

  /**
   * @return the message source identifier.
   */
  public String getMessageSourceID() {
    return this.messageSourceID;
  }

  /**
   * @return the message
   */
  @Override
  public byte[] get() {
    return this.theBytes;
  }
}