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
  26 /**
  27  * Wrapper around an {@link InputStream} that remembers all bytes that have been
  28  * read from the wrapped input stream. The remembered bytes can be retrieved
  29  * from this stream as another input stream, suitable for use with {@link
  30  * java.io.SequenceInputStream}.
  31  *
  32  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  33  */
  34 public class RememberingInputStream extends FilterInputStream {
  35
  36         /** The buffer for the read bytes. */
  37         private final ByteArrayOutputStream rememberBuffer = new ByteArrayOutputStream();
  38
  39         /**
  40          * Creates a new remembering input stream.
  41          *
  42          * @param inputStream
  43          *              The input stream to remember
  44          */
  45         public RememberingInputStream(InputStream inputStream) {
  46                 super(inputStream);
  47         }
  48
  49         //
  50         // ACCESSORS
  51         //
  52
  53         /**
  54          * Returns all remembered bytes as an {@link InputStream}.
  55          *
  56          * @return All remembered bytes
  57          */
  58         public InputStream remembered() {
  59                 return new ByteArrayInputStream(rememberBuffer.toByteArray());
  60         }
  61
  62         //
  63         // INPUTSTREAM METHODS
  64         //
  65
  66         @Override
  67         public boolean markSupported() {
  68                 return false;
  69         }
  70
  71         @Override
  72         public int read() throws IOException {
  73                 int read = super.read();
  74                 if (read != -1) {
  75                         rememberBuffer.write(read);
  76                 }
  77                 return read;
  78         }
  79
  80         @Override
  81         public int read(byte[] bytes) throws IOException {
  82                 int read = super.read(bytes);
  83                 if (read != -1) {
  84                         rememberBuffer.write(bytes, 0, read);
  85                 }
  86                 return read;
  87         }
  88
  89         @Override
  90         public int read(byte[] bytes, int offset, int length) throws IOException {
  91                 int read = super.read(bytes, offset, length);
  92                 if (read != -1) {
  93                         rememberBuffer.write(bytes, offset, read);
  94                 }
  95                 return read;
  96         }
  97
  98         @Override
  99         public synchronized void reset() throws IOException {
 100                 throw new IOException("mark()/reset() not supported");
 101         }
 102
 103         /**
 104          * {@inheritDoc} <p> This method disallows seeking and always returns {@code
 105          * 0}. </p>
 106          */
 107         @Override
 108         public long skip(long l) throws IOException {
 109                 return 0;
 110         }
 111
 112 }