/*
* 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.zeppelin.notebook.repo.zeppelinhub.websocket.scheduler;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
/**
* Creates a thread pool that can schedule zeppelinhub commands.
*
*/
public class SchedulerService {
private final ScheduledExecutorService pool;
private static SchedulerService instance = null;
private SchedulerService(int numberOfThread) {
pool = Executors.newScheduledThreadPool(numberOfThread);
}
public static SchedulerService create(int numberOfThread) {
if (instance == null) {
instance = new SchedulerService(numberOfThread);
}
return instance;
}
public static SchedulerService getInstance() {
if (instance == null) {
instance = new SchedulerService(2);
}
return instance;
}
public void add(Runnable service, int firstExecution, int period) {
pool.scheduleAtFixedRate(service, firstExecution, period, TimeUnit.SECONDS);
}
public void addOnce(Runnable service, int firstExecution) {
pool.schedule(service, firstExecution, TimeUnit.SECONDS);
}
public void close() {
pool.shutdown();
}
}