| /* |
| * 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.commons.io.input; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.InterruptedIOException; |
| import java.time.Duration; |
| import java.time.temporal.ChronoUnit; |
| import java.util.concurrent.TimeUnit; |
| |
| import org.apache.commons.io.build.AbstractStreamBuilder; |
| |
| /** |
| * 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 short interval, the average tends towards the |
| * specified maximum, overall.) |
| * <p> |
| * Inspired by Apache HBase's class of the same name. |
| * </p> |
| * |
| * @since 2.16.0 |
| */ |
| public final class ThrottledInputStream extends CountingInputStream { |
| |
| /** |
| * Builds a new {@link ThrottledInputStream} instance. |
| * <h2>Using NIO</h2> |
| * |
| * <pre>{@code |
| * ThrottledInputStream in = ThrottledInputStream.builder().setPath(Paths.get("MyFile.xml")).setMaxBytesPerSecond(100_000).get(); |
| * } |
| * </pre> |
| * |
| * <h2>Using IO</h2> |
| * |
| * <pre>{@code |
| * ThrottledInputStream in = ThrottledInputStream.builder().setFile(new File("MyFile.xml")).setMaxBytesPerSecond(100_000).get(); |
| * } |
| * </pre> |
| * |
| * <pre>{@code |
| * ThrottledInputStream in = ThrottledInputStream.builder().setInputStream(inputStream).setMaxBytesPerSecond(100_000).get(); |
| * } |
| * </pre> |
| */ |
| public static class Builder extends AbstractStreamBuilder<ThrottledInputStream, Builder> { |
| |
| /** |
| * Effectively not throttled. |
| */ |
| private long maxBytesPerSecond = Long.MAX_VALUE; |
| |
| /** |
| * Constructs a new instance. |
| * <p> |
| * You must provide an origin that supports calling {@link #getInputStream()} on this builder, otherwise, this method throws an exception. |
| * </p> |
| * |
| * @return a new instance. |
| * @throws IllegalStateException if the {@code origin} is {@code null}. |
| * @throws UnsupportedOperationException if the origin cannot be converted to an {@link InputStream}. |
| * @throws IOException if an I/O error occurs. |
| * @see #getInputStream() |
| */ |
| @SuppressWarnings("resource") |
| @Override |
| public ThrottledInputStream get() throws IOException { |
| return new ThrottledInputStream(getInputStream(), maxBytesPerSecond); |
| } |
| |
| /** |
| * Sets the maximum bytes per second. |
| * |
| * @param maxBytesPerSecond the maximum bytes per second. |
| */ |
| public void setMaxBytesPerSecond(final long maxBytesPerSecond) { |
| this.maxBytesPerSecond = maxBytesPerSecond; |
| } |
| |
| } |
| |
| /** |
| * Constructs a new {@link Builder}. |
| * |
| * @return a new {@link Builder}. |
| */ |
| public static Builder builder() { |
| return new Builder(); |
| } |
| |
| static long toSleepMillis(final long bytesRead, final long maxBytesPerSec, final long elapsedMillis) { |
| assert elapsedMillis >= 0 : "The elapsed time should be greater or equal to zero"; |
| if (bytesRead <= 0 || maxBytesPerSec <= 0 || elapsedMillis == 0) { |
| return 0; |
| } |
| // We use this class to load the single source file, so the bytesRead |
| // and maxBytesPerSec aren't greater than Double.MAX_VALUE. |
| // We can get the precise sleep time by using the double value. |
| final long millis = (long) ((double) bytesRead / (double) maxBytesPerSec * 1000 - elapsedMillis); |
| if (millis <= 0) { |
| return 0; |
| } |
| return millis; |
| } |
| |
| private final long maxBytesPerSecond; |
| private final long startTime = System.currentTimeMillis(); |
| private Duration totalSleepDuration = Duration.ZERO; |
| |
| private ThrottledInputStream(final InputStream proxy, final long maxBytesPerSecond) { |
| super(proxy); |
| assert maxBytesPerSecond > 0 : "Bandwidth " + maxBytesPerSecond + " is invalid."; |
| this.maxBytesPerSecond = maxBytesPerSecond; |
| } |
| |
| @Override |
| protected void beforeRead(final int n) throws IOException { |
| throttle(); |
| } |
| |
| /** |
| * Gets the read-rate from this stream, since creation. Calculated as bytesRead/elapsedTimeSinceStart. |
| * |
| * @return Read rate, in bytes/sec. |
| */ |
| private long getBytesPerSecond() { |
| final long elapsedSeconds = (System.currentTimeMillis() - startTime) / 1000; |
| if (elapsedSeconds == 0) { |
| return getByteCount(); |
| } |
| return getByteCount() / elapsedSeconds; |
| } |
| |
| private long getSleepMillis() { |
| return toSleepMillis(getByteCount(), maxBytesPerSecond, System.currentTimeMillis() - startTime); |
| } |
| |
| /** |
| * Gets the total duration spent in sleep. |
| * |
| * @return Duration spent in sleep. |
| */ |
| Duration getTotalSleepDuration() { |
| return totalSleepDuration; |
| } |
| |
| private void throttle() throws InterruptedIOException { |
| final long sleepMillis = getSleepMillis(); |
| if (sleepMillis > 0) { |
| totalSleepDuration = totalSleepDuration.plus(sleepMillis, ChronoUnit.MILLIS); |
| try { |
| TimeUnit.MILLISECONDS.sleep(sleepMillis); |
| } catch (final InterruptedException e) { |
| throw new InterruptedIOException("Thread aborted"); |
| } |
| } |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public String toString() { |
| return "ThrottledInputStream[bytesRead=" + getByteCount() + ", maxBytesPerSec=" + maxBytesPerSecond + ", bytesPerSec=" + getBytesPerSecond() |
| + ", totalSleepDuration=" + totalSleepDuration + ']'; |
| } |
| } |