org.apache.pig.backend.executionengine.ExecJob Maven / Gradle / Ivy
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* 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 org.apache.pig.backend.executionengine;
import java.util.Iterator;
import java.util.Properties;
import java.io.OutputStream;
import org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POStore;
import org.apache.pig.data.Tuple;
import org.apache.pig.tools.pigstats.PigStats;
/**
* Abstraction on a job that the execution engine runs. It allows the front-end to
* retrieve information on job status and manage a running job.
*
*/
public interface ExecJob {
public enum JOB_STATUS {
FAILED,
COMPLETED
}
public static final String PROGRESS_KEY = "job.progress";
public JOB_STATUS getStatus();
/**
* true is the physical plan has executed successfully and results are ready
* to be retrieved
*
* @return true if execution has completed, false otherwise.
* @throws ExecException
*/
public boolean hasCompleted() throws ExecException;
/**
* if query has executed successfully we want to retrieve the results
* via iterating over them.
*
* @return iterator for resulting tuples
* @throws ExecException
*/
public Iterator getResults() throws ExecException;
/**
* Returns the alias of relation generated by this job
*/
public String getAlias() throws ExecException;
/**
* Get configuration information
*
* @return configuration information for the execution engine
*/
public Properties getConfiguration();
/**
* Can be information about the state (not submitted, e.g. the execute method
* has not been called yet; not running, e.g. execute has been issued,
* but job is waiting; running...; completed; aborted...; progress information
*
* @return statistics relevant to the execution engine
*/
public PigStats getStatistics();
/**
*
* @return {@link POStore} object associated with the store
*/
public POStore getPOStore();
/**
* hook for asynchronous notification of job completion pushed from the back-end
*/
public void completionNotification(Object cookie);
/**
* Kills current job.
*
* @throws ExecException
*/
public void kill() throws ExecException;
/**
* Collecting various forms of outputs
*/
public void getLogs(OutputStream log) throws ExecException;
public void getSTDOut(OutputStream out) throws ExecException;
public void getSTDError(OutputStream error) throws ExecException;
/**
* Get exceptions that happened during execution
*/
public Exception getException();
}