helix-core/src/main/java/org/apache/helix/controller/pipeline/AbstractBaseStage.java

package org.apache.helix.controller.pipeline;

/*
 * 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.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;

import org.apache.helix.common.DedupEventProcessor;
import org.apache.helix.controller.stages.AttributeName;
import org.apache.helix.controller.stages.ClusterEvent;

public class AbstractBaseStage implements Stage {
  protected String _eventId;

  @Override
  public void init(StageContext context) {

  }

  @Override
  public void preProcess() {
    // TODO Auto-generated method stub

  }

  @Override
  public void process(ClusterEvent event) throws Exception {

  }

  @Override
  public void postProcess() {

  }

  @Override
  public void release() {

  }

  @Override
  public String getStageName() {
    // default stage name will be the class name
    String className = this.getClass().getSimpleName();
    return className;
  }

  public static <T> Future asyncExecute(ExecutorService service, Callable<T> task) {
    if (service != null) {
      return service.submit(task);
    }
    return null;
  }

  protected DedupEventProcessor<String, Runnable> getAsyncWorkerFromClusterEvent(ClusterEvent event,
      AsyncWorkerType workerType) {
    Map<AsyncWorkerType, DedupEventProcessor<String, Runnable>> workerPool =
        event.getAttribute(AttributeName.AsyncFIFOWorkerPool.name());
    if (workerPool != null) {
      if (workerPool.containsKey(workerType)) {
        return workerPool.get(workerType);
      }
    }
    return null;
  }
}