/**
* 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.hadoop.hive.metastore;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.api.MetaException;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* A thread that runs in the metastore, separate from the threads in the thrift service.
*/
public interface MetaStoreThread {
/**
* Set the Hive configuration for this thread.
* @param conf
*/
void setHiveConf(HiveConf conf);
/**
* Set the id for this thread.
* @param threadId
*/
void setThreadId(int threadId);
/**
* Initialize the thread. This must not be called until after
* {@link #setHiveConf(org.apache.hadoop.hive.conf.HiveConf)} and {@link #setThreadId(int)}
* have been called.
* @param stop a flag to watch for when to stop. If this value is set to true,
* the thread will terminate the next time through its main loop.
* @param looped a flag that is set to true everytime a thread goes through it's main loop.
* This is purely for testing so that tests can assure themselves that the thread
* has run through it's loop once. The test can set this value to false. The
* thread should then assure that the loop has been gone completely through at
* least once.
*/
void init(AtomicBoolean stop, AtomicBoolean looped) throws MetaException;
/**
* Run the thread in the background. This must not be called until
* {@link ##init(java.util.concurrent.atomic.AtomicBoolean, java.util.concurrent.atomic.AtomicBoolean)} has
* been called.
*/
void start();
}