helix-core/src/main/java/org/apache/helix/manager/zk/DefaultControllerMessageHandlerFactory.java

package org.apache.helix.manager.zk;

/*
 * 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.
 */

import java.util.List;

import org.apache.helix.HelixException;
import org.apache.helix.NotificationContext;
import org.apache.helix.messaging.handling.HelixTaskResult;
import org.apache.helix.messaging.handling.MessageHandler;
import org.apache.helix.messaging.handling.MessageHandlerFactory;
import org.apache.helix.messaging.handling.MultiTypeMessageHandlerFactory;
import org.apache.helix.model.Message;
import org.apache.helix.model.Message.MessageType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.ImmutableList;

public class DefaultControllerMessageHandlerFactory implements MultiTypeMessageHandlerFactory {
  private static Logger _logger = LoggerFactory.getLogger(DefaultControllerMessageHandlerFactory.class);

  @Override
  public MessageHandler createHandler(Message message, NotificationContext context) {
    String type = message.getMsgType();

    if (!type.equals(getMessageType())) {
      throw new HelixException("Unexpected msg type for message " + message.getMsgId() + " type:"
          + message.getMsgType());
    }

    return new DefaultControllerMessageHandler(message, context);
  }

  @Override
  public String getMessageType() {
    return MessageType.CONTROLLER_MSG.name();
  }

  @Override
  public List<String> getMessageTypes() {
    return ImmutableList.of(MessageType.CONTROLLER_MSG.name());
  }

  @Override
  public void reset() {

  }

  public static class DefaultControllerMessageHandler extends MessageHandler {
    public DefaultControllerMessageHandler(Message message, NotificationContext context) {
      super(message, context);
    }

    @Override
    public HelixTaskResult handleMessage() throws InterruptedException {
      String type = _message.getMsgType();
      HelixTaskResult result = new HelixTaskResult();
      if (!type.equals(MessageType.CONTROLLER_MSG.name())) {
        throw new HelixException("Unexpected msg type for message " + _message.getMsgId()
            + " type:" + _message.getMsgType());
      }
      result.getTaskResultMap().put("ControllerResult",
          "msg " + _message.getMsgId() + " from " + _message.getMsgSrc() + " processed");
      result.setSuccess(true);
      return result;
    }

    @Override
    public void onError(Exception e, ErrorCode code, ErrorType type) {
      _logger.error("Message handling pipeline get an exception. MsgId:" + _message.getMsgId(), e);
    }
  }
}