src/main/java/net/pterodactylus/sonitus/io/RememberingInputStream.java

   1 /*
   2  * Sonitus - RememberingInputStream.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.io;
  19
  20 import java.io.ByteArrayInputStream;
  21 import java.io.ByteArrayOutputStream;
  22 import java.io.FilterInputStream;
  23 import java.io.IOException;
  24 import java.io.InputStream;
  25 import java.io.SequenceInputStream;
  26
  27 /**
  28  * Wrapper around an {@link InputStream} that remembers all bytes that have been
  29  * read from the wrapped input stream. The remembered bytes can be retrieved
  30  * from this stream as another input stream, suitable for use with {@link
  31  * java.io.SequenceInputStream}.
  32  *
  33  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  34  */
  35 public class RememberingInputStream extends FilterInputStream {
  36
  37         /** The buffer for the read bytes. */
  38         private final ByteArrayOutputStream rememberBuffer = new ByteArrayOutputStream();
  39
  40         /**
  41          * Creates a new remembering input stream.
  42          *
  43          * @param inputStream
  44          *              The input stream to remember
  45          */
  46         public RememberingInputStream(InputStream inputStream) {
  47                 super(inputStream);
  48         }
  49
  50         //
  51         // ACCESSORS
  52         //
  53
  54         /**
  55          * Returns an input stream that repeats the originally wrapped stream,
  56          * including all bytes that have already been read.
  57          *
  58          * @return A new input stream with the original content
  59          */
  60         public InputStream remembered() {
  61                 return new SequenceInputStream(new ByteArrayInputStream(rememberBuffer.toByteArray()), in);
  62         }
  63
  64         //
  65         // INPUTSTREAM METHODS
  66         //
  67
  68         @Override
  69         public boolean markSupported() {
  70                 return false;
  71         }
  72
  73         @Override
  74         public int read() throws IOException {
  75                 int read = super.read();
  76                 if (read != -1) {
  77                         rememberBuffer.write(read);
  78                 }
  79                 return read;
  80         }
  81
  82         @Override
  83         public int read(byte[] bytes) throws IOException {
  84                 return read(bytes, 0, bytes.length);
  85         }
  86
  87         @Override
  88         public int read(byte[] bytes, int offset, int length) throws IOException {
  89                 int read = super.read(bytes, offset, length);
  90                 if (read != -1) {
  91                         rememberBuffer.write(bytes, offset, read);
  92                 }
  93                 return read;
  94         }
  95
  96         @Override
  97         public synchronized void reset() throws IOException {
  98                 throw new IOException("mark()/reset() not supported");
  99         }
 100
 101         /**
 102          * {@inheritDoc} <p> This method disallows seeking and always returns {@code
 103          * 0}. </p>
 104          */
 105         @Override
 106         public long skip(long l) throws IOException {
 107                 return 0;
 108         }
 109
 110 }