/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* 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 eu.stratosphere.nephele.execution;
public interface ExecutionObserver {
/**
* Called when the execution state of the associated task has changed.
*
* @param newExecutionState
* the execution state the task has just switched to
* @param optionalMessage
* an optional message providing further information on the state change
*/
void executionStateChanged(ExecutionState newExecutionState, String optionalMessage);
/**
* Called when the user task has started a new thread.
*
* @param userThread
* the user thread which has been started
*/
void userThreadStarted(Thread userThread);
/**
* Called when a thread spawn by a user task has finished.
*
* @param userThread
* the user thread which has finished
*/
void userThreadFinished(Thread userThread);
/**
* Returns whether the task has been canceled.
*
* @return <code>true</code> if the task has been canceled, <code>false</code> otherwise
*/
boolean isCanceled();
}