forked from cwensel/cascading
/
FlowListener.java
63 lines (58 loc) · 2.1 KB
/
FlowListener.java
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/*
* Copyright (c) 2007-2013 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* 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 cascading.flow;
/**
* Interface FlowListener provides hooks for receiving events on various stages of a {@link Flow} execution.
* <p/>
* Any {@link RuntimeException} thrown from any of the listener methods will force the given {@code flow} to
* stop by calling {@link Flow#stop()}.
*/
public interface FlowListener
{
/**
* The onStarting event is fired when a Flow instance receives the start() message.
*
* @param flow
*/
void onStarting( Flow flow );
/**
* The onStopping event is fired when a Flow instance receives the stop() message.
*
* @param flow
*/
void onStopping( Flow flow );
/**
* The onCompleted event is fired when a Flow instance has completed all work whether if was success or failed. If
* there was a thrown exception, onThrowable will be fired before this event.
*
* @param flow
*/
void onCompleted( Flow flow );
/**
* The onThrowable event is fired if any child {@link cascading.flow.FlowStep} throws a Throwable type. This throwable is passed
* as an argument to the event. This event method should return true if the given throwable was handled and should
* not be rethrown from the {@link Flow#complete()} method.
*
* @param flow
* @param throwable
* @return returns true if this listener has handled the given throwable
*/
boolean onThrowable( Flow flow, Throwable throwable );
}