src/main/java/net/pterodactylus/sonitus/data/filter/RateLimitingFilter.java

   1 /*
   2  * Sonitus - DelayFilter.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sonitus.data.filter;
  19
  20 import static com.google.common.io.Closeables.close;
  21
  22 import java.io.EOFException;
  23 import java.io.IOException;
  24 import java.io.PipedInputStream;
  25 import java.io.PipedOutputStream;
  26 import java.util.Arrays;
  27 import java.util.logging.Logger;
  28
  29 import net.pterodactylus.sonitus.data.ConnectException;
  30 import net.pterodactylus.sonitus.data.Connection;
  31 import net.pterodactylus.sonitus.data.Filter;
  32 import net.pterodactylus.sonitus.data.Format;
  33 import net.pterodactylus.sonitus.data.Metadata;
  34 import net.pterodactylus.sonitus.data.Source;
  35
  36 import com.google.common.base.Preconditions;
  37
  38 /**
  39  * Rate limiting filter that only passes a specified amount of data per second
  40  * from its {@link Source} to its {@link net.pterodactylus.sonitus.data.Sink}.
  41  *
  42  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  43  */
  44 public class RateLimitingFilter implements Filter {
  45
  46         /** The logger. */
  47         private static final Logger logger = Logger.getLogger(RateLimitingFilter.class.getName());
  48
  49         /** The limiting rate in bytes/second. */
  50         private final int rate;
  51
  52         /** The source’s format. */
  53         private Source source;
  54
  55         /** The input stream to read from. */
  56         private PipedInputStream pipedInputStream = new PipedInputStream();
  57
  58         /**
  59          * Creates a new rate limiting filter.
  60          *
  61          * @param rate
  62          *              The limiting rate (in bytes/second)
  63          */
  64         public RateLimitingFilter(int rate) {
  65                 this.rate = rate;
  66         }
  67
  68         //
  69         // FILTER METHODS
  70         //
  71
  72         @Override
  73         public Format format() {
  74                 return source.format();
  75         }
  76
  77         @Override
  78         public Metadata metadata() {
  79                 return source.metadata();
  80         }
  81
  82         @Override
  83         public byte[] get(int bufferSize) throws EOFException, IOException {
  84                 byte[] buffer = new byte[bufferSize];
  85                 int read = pipedInputStream.read(buffer);
  86                 if (read == -1) {
  87                         throw new EOFException();
  88                 }
  89                 return Arrays.copyOf(buffer, read);
  90         }
  91
  92         @Override
  93         public void connect(Source source) throws ConnectException {
  94                 Preconditions.checkNotNull(source, "source must not be null");
  95
  96                 this.source = source;
  97                 final long start = System.currentTimeMillis();
  98                 try {
  99                         pipedInputStream = new PipedInputStream();
 100                         final PipedOutputStream pipedOutputStream = new PipedOutputStream(pipedInputStream);
 101                         new Thread(new Connection(source) {
 102
 103                                 @Override
 104                                 protected int bufferSize() {
 105                                         return rate;
 106                                 }
 107
 108                                 @Override
 109                                 protected void feed(byte[] buffer) throws IOException {
 110                                         long waitTime = 1000 * buffer.length / rate;
 111                                         long now = System.currentTimeMillis();
 112                                         pipedOutputStream.write(buffer);
 113                                         pipedOutputStream.flush();
 114                                         while ((System.currentTimeMillis() - now) < waitTime) {
 115                                                 try {
 116                                                         long limitDelay = waitTime - (System.currentTimeMillis() - now);
 117                                                         logger.finest(String.format("Waiting %d ms...", limitDelay));
 118                                                         Thread.sleep(limitDelay);
 119                                                 } catch (InterruptedException ie1) {
 120                                                         /* ignore, keep looping. */
 121                                                 }
 122                                         }
 123                                 }
 124
 125                                 @Override
 126                                 protected void finish() throws IOException {
 127                                         close(pipedInputStream, true);
 128                                         close(pipedOutputStream, true);
 129                                 }
 130                         }).start();
 131                 } catch (IOException ioe1) {
 132                         throw new ConnectException(ioe1);
 133                 }
 134         }
 135
 136 }