/**
* 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 storm.trident.operation;
import java.io.Serializable;
import java.util.Map;
/**
* Parent interface for Trident `Filter`s and `Function`s.
*
* `Operation` defines two lifecycle methods for Trident components. The `prepare()` method is called once when the
* `Operation` is first initialized. The `cleanup()` method is called in local mode when the local cluster is
* being shut down. In distributed mode, the `cleanup()` method is not guaranteed to be called in every situation, but
* Storm will make a best effort call `cleanup()` whenever possible.
*/
public interface Operation extends Serializable {
/**
* Called when the `Operation` is first initialized.
* @param conf the Storm configuration map
* @param context the operation context which provides information such as the number of partitions in the stream,
* and the current partition index. It also provides methods for registering operation-specific
* metrics.
* @see org.apache.storm.trident.operation.TridentOperationContext
*/
void prepare(Map conf, TridentOperationContext context);
/**
* When running in local mode, called when the local cluster is being shut down.
*/
void cleanup();
}