/**
* Copyright 2010 The Apache Software Foundation
*
* 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.hbase.master;
import java.io.IOException;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.concurrent.Executors;
import org.apache.hadoop.hbase.Server;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
/**
* Base class used bulk assigning and unassigning regions.
* Encapsulates a fixed size thread pool of executors to run assignment/unassignment.
* Implement {@link #populatePool(java.util.concurrent.ExecutorService)} and
* {@link #waitUntilDone(long)}. The default implementation of
* the {@link #getUncaughtExceptionHandler()} is to abort the hosting
* Server.
*/
public abstract class BulkAssigner {
protected final Server server;
/**
* @param server An instance of Server
*/
public BulkAssigner(final Server server) {
this.server = server;
}
/**
* @return What to use for a thread prefix when executor runs.
*/
protected String getThreadNamePrefix() {
return this.server.getServerName() + "-" + this.getClass().getName();
}
protected UncaughtExceptionHandler getUncaughtExceptionHandler() {
return new UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
// Abort if exception of any kind.
server.abort("Uncaught exception in " + t.getName(), e);
}
};
}
protected int getThreadCount() {
return this.server.getConfiguration().
getInt("hbase.bulk.assignment.threadpool.size", 20);
}
protected long getTimeoutOnRIT() {
return this.server.getConfiguration().
getLong("hbase.bulk.assignment.waiton.empty.rit", 5 * 60 * 1000);
}
protected abstract void populatePool(
final java.util.concurrent.ExecutorService pool) throws IOException;
public boolean bulkAssign() throws InterruptedException, IOException {
return bulkAssign(true);
}
/**
* Run the bulk assign.
*
* @param sync
* Whether to assign synchronously.
* @throws InterruptedException
* @return True if done.
* @throws IOException
*/
public boolean bulkAssign(boolean sync) throws InterruptedException,
IOException {
boolean result = false;
ThreadFactoryBuilder builder = new ThreadFactoryBuilder();
builder.setDaemon(true);
builder.setNameFormat(getThreadNamePrefix() + "-%1$d");
builder.setUncaughtExceptionHandler(getUncaughtExceptionHandler());
int threadCount = getThreadCount();
java.util.concurrent.ExecutorService pool =
Executors.newFixedThreadPool(threadCount, builder.build());
try {
populatePool(pool);
// How long to wait on empty regions-in-transition. If we timeout, the
// RIT monitor should do fixup.
if (sync) result = waitUntilDone(getTimeoutOnRIT());
} finally {
// We're done with the pool. It'll exit when its done all in queue.
pool.shutdown();
}
return result;
}
/**
* Wait until bulk assign is done.
* @param timeout How long to wait.
* @throws InterruptedException
* @return True if the condition we were waiting on happened.
*/
protected abstract boolean waitUntilDone(final long timeout)
throws InterruptedException;
}