org.apache.hadoop.hbase.ipc.FifoRpcScheduler.java Source code

Introduction

Here is the source code for org.apache.hadoop.hbase.ipc.FifoRpcScheduler.java

Source

/**
 * 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.ipc;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.DaemonThreadFactory;

import java.io.IOException;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * A very simple {@code }RpcScheduler} that serves incoming requests in order.
 *
 * This can be used for HMaster, where no prioritization is needed.
 */
public class FifoRpcScheduler extends RpcScheduler {
    private static final Log LOG = LogFactory.getLog(FifoRpcScheduler.class);
    private final int handlerCount;
    private final int maxQueueLength;
    private final AtomicInteger queueSize = new AtomicInteger(0);
    private ThreadPoolExecutor executor;

    public FifoRpcScheduler(Configuration conf, int handlerCount) {
        this.handlerCount = handlerCount;
        this.maxQueueLength = conf.getInt(RpcScheduler.IPC_SERVER_MAX_CALLQUEUE_LENGTH,
                handlerCount * RpcServer.DEFAULT_MAX_CALLQUEUE_LENGTH_PER_HANDLER);
        LOG.info("Using " + this.getClass().getSimpleName() + " as user call queue; handlerCount=" + handlerCount
                + "; maxQueueLength=" + maxQueueLength);
    }

    @Override
    public void init(Context context) {
        // no-op
    }

    @Override
    public void start() {
        this.executor = new ThreadPoolExecutor(handlerCount, handlerCount, 60, TimeUnit.SECONDS,
                new ArrayBlockingQueue<Runnable>(maxQueueLength),
                new DaemonThreadFactory("FifoRpcScheduler.handler"), new ThreadPoolExecutor.CallerRunsPolicy());
    }

    @Override
    public void stop() {
        this.executor.shutdown();
    }

    @Override
    public boolean dispatch(final CallRunner task) throws IOException, InterruptedException {
        // Executors provide no offer, so make our own.
        int queued = queueSize.getAndIncrement();
        if (maxQueueLength > 0 && queued >= maxQueueLength) {
            queueSize.decrementAndGet();
            return false;
        }
        executor.submit(new Runnable() {
            @Override
            public void run() {
                task.setStatus(RpcServer.getStatus());
                task.run();
                queueSize.decrementAndGet();
            }
        });
        return true;
    }

    @Override
    public int getGeneralQueueLength() {
        return executor.getQueue().size();
    }

    @Override
    public int getPriorityQueueLength() {
        return 0;
    }

    @Override
    public int getReplicationQueueLength() {
        return 0;
    }

    @Override
    public int getActiveRpcHandlerCount() {
        return executor.getActiveCount();
    }

    @Override
    public long getNumGeneralCallsDropped() {
        return 0;
    }

    @Override
    public long getNumLifoModeSwitches() {
        return 0;
    }
}