| /** |
| * 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.apex.malhar.lib.bandwidth; |
| |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.datatorrent.api.Component; |
| import com.datatorrent.api.Context; |
| import com.datatorrent.api.Context.OperatorContext; |
| |
| /** |
| * BandwidthManager keeps track of bandwidth consumption and provides limit on maximum bandwidth that can be consumed at |
| * any moment. This accumulates bandwidth upto certain limits so that accumulated bandwidth can be used over a period of |
| * time. |
| * |
| * @since 3.5.0 |
| */ |
| public class BandwidthManager implements Component<Context.OperatorContext> |
| { |
| private static final Logger LOG = LoggerFactory.getLogger(BandwidthManager.class); |
| /** |
| * Maximum bandwidth that can be consumed in bytes/sec |
| */ |
| private long bandwidthLimit = Long.MAX_VALUE; |
| private transient long currentBandwidthConsumption; |
| private final transient ScheduledExecutorService scheduler; |
| private final transient Object lock = new Object(); |
| |
| public BandwidthManager() |
| { |
| scheduler = Executors.newScheduledThreadPool(1); |
| } |
| |
| BandwidthManager(ScheduledExecutorService scheduler) |
| { |
| this.scheduler = scheduler; |
| } |
| |
| @Override |
| public void setup(OperatorContext context) |
| { |
| scheduler.scheduleAtFixedRate(new Runnable() |
| { |
| @Override |
| public void run() |
| { |
| if (isBandwidthRestricted()) { |
| synchronized (lock) { |
| if (currentBandwidthConsumption < 0) { |
| currentBandwidthConsumption += bandwidthLimit; |
| } else { |
| currentBandwidthConsumption = bandwidthLimit; |
| } |
| LOG.debug("Available bandwidth: " + currentBandwidthConsumption); |
| } |
| } |
| } |
| }, 1, 1, TimeUnit.SECONDS); |
| } |
| |
| public boolean canConsumeBandwidth() |
| { |
| if (!isBandwidthRestricted()) { |
| return true; |
| } |
| synchronized (lock) { |
| return currentBandwidthConsumption >= 0; |
| } |
| } |
| |
| public void consumeBandwidth(long sentTupleSize) |
| { |
| if (isBandwidthRestricted()) { |
| synchronized (lock) { |
| currentBandwidthConsumption -= sentTupleSize; |
| } |
| } |
| } |
| |
| public boolean isBandwidthRestricted() |
| { |
| return bandwidthLimit != Long.MAX_VALUE; |
| } |
| |
| /** |
| * get maximum bandwidth that can be consumed in bytes/sec |
| * |
| * @return |
| */ |
| public long getBandwidth() |
| { |
| return bandwidthLimit; |
| } |
| |
| /** |
| * Set maximum bandwidth that can be consumed in bytes/sec |
| * |
| * @param bandwidth |
| */ |
| public void setBandwidth(long bandwidth) |
| { |
| this.bandwidthLimit = bandwidth; |
| LOG.debug("Bandwidth limit is set to: " + bandwidth + " bytes/sec"); |
| } |
| |
| @Override |
| public void teardown() |
| { |
| scheduler.shutdownNow(); |
| } |
| |
| } |