| /** |
| * 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.tools.util; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * The ThrottleInputStream provides bandwidth throttling on a specified |
| * InputStream. It is implemented as a wrapper on top of another InputStream |
| * instance. |
| * The throttling works by examining the number of bytes read from the underlying |
| * InputStream from the beginning, and sleep()ing for a time interval if |
| * the byte-transfer is found exceed the specified tolerable maximum. |
| * (Thus, while the read-rate might exceed the maximum for a given short interval, |
| * the average tends towards the specified maximum, overall.) |
| */ |
| public class ThrottledInputStream extends InputStream { |
| |
| private final InputStream rawStream; |
| private final long maxBytesPerSec; |
| private final long startTime = System.currentTimeMillis(); |
| |
| private long bytesRead = 0; |
| private long totalSleepTime = 0; |
| |
| private static final long SLEEP_DURATION_MS = 50; |
| |
| public ThrottledInputStream(InputStream rawStream) { |
| this(rawStream, Long.MAX_VALUE); |
| } |
| |
| public ThrottledInputStream(InputStream rawStream, long maxBytesPerSec) { |
| assert maxBytesPerSec > 0 : "Bandwidth " + maxBytesPerSec + " is invalid"; |
| this.rawStream = rawStream; |
| this.maxBytesPerSec = maxBytesPerSec; |
| } |
| |
| /** @inheritDoc */ |
| @Override |
| public int read() throws IOException { |
| throttle(); |
| int data = rawStream.read(); |
| if (data != -1) { |
| bytesRead++; |
| } |
| return data; |
| } |
| |
| /** @inheritDoc */ |
| @Override |
| public int read(byte[] b) throws IOException { |
| throttle(); |
| int readLen = rawStream.read(b); |
| if (readLen != -1) { |
| bytesRead += readLen; |
| } |
| return readLen; |
| } |
| |
| /** @inheritDoc */ |
| @Override |
| public int read(byte[] b, int off, int len) throws IOException { |
| throttle(); |
| int readLen = rawStream.read(b, off, len); |
| if (readLen != -1) { |
| bytesRead += readLen; |
| } |
| return readLen; |
| } |
| |
| private void throttle() throws IOException { |
| if (getBytesPerSec() > maxBytesPerSec) { |
| try { |
| Thread.sleep(SLEEP_DURATION_MS); |
| totalSleepTime += SLEEP_DURATION_MS; |
| } catch (InterruptedException e) { |
| throw new IOException("Thread aborted", e); |
| } |
| } |
| } |
| |
| /** |
| * Getter for the number of bytes read from this stream, since creation. |
| * @return The number of bytes. |
| */ |
| public long getTotalBytesRead() { |
| return bytesRead; |
| } |
| |
| /** |
| * Getter for the read-rate from this stream, since creation. |
| * Calculated as bytesRead/elapsedTimeSinceStart. |
| * @return Read rate, in bytes/sec. |
| */ |
| public long getBytesPerSec() { |
| long elapsed = (System.currentTimeMillis() - startTime) / 1000; |
| if (elapsed == 0) { |
| return bytesRead; |
| } else { |
| return bytesRead / elapsed; |
| } |
| } |
| |
| /** |
| * Getter the total time spent in sleep. |
| * @return Number of milliseconds spent in sleep. |
| */ |
| public long getTotalSleepTime() { |
| return totalSleepTime; |
| } |
| |
| /** @inheritDoc */ |
| @Override |
| public String toString() { |
| return "ThrottledInputStream{" + |
| "bytesRead=" + bytesRead + |
| ", maxBytesPerSec=" + maxBytesPerSec + |
| ", bytesPerSec=" + getBytesPerSec() + |
| ", totalSleepTime=" + totalSleepTime + |
| '}'; |
| } |
| } |