ExecutorProvider.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * 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 com.yahoo.pulsar.client.util;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;

import com.google.common.collect.Lists;

import io.netty.util.concurrent.DefaultThreadFactory;

public class ExecutorProvider {
    private final int numThreads;
    private final List<ExecutorService> executors;
    private final AtomicInteger currentThread = new AtomicInteger(0);

    public ExecutorProvider(int numThreads, String threadNamePrefix) {
        checkArgument(numThreads > 0);
        this.numThreads = numThreads;
        checkNotNull(threadNamePrefix);
        executors = Lists.newArrayListWithCapacity(numThreads);
        for (int i = 0; i < numThreads; i++) {
            executors.add(Executors.newSingleThreadExecutor(new DefaultThreadFactory(threadNamePrefix)));
        }
    }

    public ExecutorService getExecutor() {
        return executors.get((currentThread.getAndIncrement() & Integer.MAX_VALUE) % numThreads);
    }

    public void shutdownNow() {
        executors.forEach(executor -> executor.shutdownNow());
    }
}