Source for javax.imageio.stream.FileCacheImageOutputStream

 1:  /* FileCacheImageOutputStream.java --
 2:  Copyright (C) 2004 Free Software Foundation, Inc.
 3: 
 4: This file is part of GNU Classpath.
 5: 
 6: GNU Classpath is free software; you can redistribute it and/or modify
 7: it under the terms of the GNU General Public License as published by
 8: the Free Software Foundation; either version 2, or (at your option)
 9: any later version.
 10: 
 11: GNU Classpath is distributed in the hope that it will be useful, but
 12: WITHOUT ANY WARRANTY; without even the implied warranty of
 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 14: General Public License for more details.
 15: 
 16: You should have received a copy of the GNU General Public License
 17: along with GNU Classpath; see the file COPYING. If not, write to the
 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 19: 02110-1301 USA.
 20: 
 21: Linking this library statically or dynamically with other modules is
 22: making a combined work based on this library. Thus, the terms and
 23: conditions of the GNU General Public License cover the whole
 24: combination.
 25: 
 26: As a special exception, the copyright holders of this library give you
 27: permission to link this library with independent modules to produce an
 28: executable, regardless of the license terms of these independent
 29: modules, and to copy and distribute the resulting executable under
 30: terms of your choice, provided that you also meet, for each linked
 31: independent module, the terms and conditions of the license of that
 32: module. An independent module is a module which is not derived from
 33: or based on this library. If you modify this library, you may extend
 34: this exception to your version of the library, but you are not
 35: obligated to do so. If you do not wish to do so, delete this
 36: exception statement from your version. */
 37: 
 38: 
 39:  package javax.imageio.stream;
 40: 
 41:  import java.io.File;
 42:  import java.io.IOException;
 43:  import java.io.OutputStream;
 44:  import java.io.RandomAccessFile;
 45: 
 46:  /**
 47:  * @author Michael Koch (konqueror@gmx.de)
 48:  */
 49:  public class FileCacheImageOutputStream extends ImageOutputStreamImpl
 50: {
 51:  private OutputStream stream;
 52:  private File cacheFile;
 53:  private RandomAccessFile cache;
 54:  private long maxPos;
 55: 
 56:  public FileCacheImageOutputStream(OutputStream s, File cacheDir)
 57:  throws IOException
 58:  {
 59:  stream = s;
 60:  cacheFile = File.createTempFile("imageio", ".tmp", cacheDir);
 61:  cache = new RandomAccessFile(cacheFile, "rw");
 62:  maxPos = 0;
 63:  }
 64: 
 65:  public void close()
 66:  throws IOException
 67:  {
 68:  maxPos = cache.length();
 69:  seek(maxPos);
 70:  flushBefore(maxPos);
 71:  super.close();
 72:  cache.close();
 73:  cacheFile.delete();
 74:  stream.flush();
 75:  stream = null;
 76:  }
 77: 
 78:  public boolean isCached()
 79:  {
 80:  return true;
 81:  }
 82: 
 83:  public boolean isCachedFile()
 84:  {
 85:  return true;
 86:  }
 87:  
 88:  public boolean isCachedMemory()
 89:  {
 90:  return false;
 91:  }
 92:  
 93:  public int read()
 94:  throws IOException
 95:  {
 96:  bitOffset = 0;
 97:  int val = cache.read();
 98:  if (val != -1)
 99:  streamPos++;
 100:  return val;
 101:  }
 102: 
 103:  public int read(byte[] data, int offset, int len)
 104:  throws IOException
 105:  {
 106:  bitOffset = 0;
 107:  int num = cache.read(data, offset, len);
 108:  if (num != -1)
 109:  streamPos += num;
 110:  return num;
 111:  }
 112: 
 113:  public void write(byte[] data, int offset, int len)
 114:  throws IOException
 115:  {
 116:  flushBits();
 117:  cache.write(data, offset, len);
 118:  streamPos += len;
 119:  maxPos = Math.max(streamPos, maxPos);
 120:  }
 121: 
 122:  public void write(int value)
 123:  throws IOException
 124:  {
 125:  flushBits();
 126:  cache.write(value);
 127:  streamPos++;
 128:  maxPos = Math.max(streamPos, maxPos);
 129:  }
 130: 
 131:  public long length()
 132:  {
 133:  long l;
 134:  try
 135:  {
 136:  l = cache.length();
 137:  }
 138:  catch (IOException ex)
 139:  {
 140:  l = -1;
 141:  }
 142:  return l;
 143:  }
 144: 
 145:  public void seek(long pos)
 146:  throws IOException
 147:  {
 148:  checkClosed();
 149:  if (pos < flushedPos)
 150:  throw new IndexOutOfBoundsException();
 151:  cache.seek(pos);
 152:  streamPos = cache.getFilePointer();
 153:  maxPos = Math.max(streamPos, maxPos);
 154:  bitOffset = 0;
 155:  }
 156: 
 157:  public void flushBefore(long pos)
 158:  throws IOException
 159:  {
 160:  long oldPos = flushedPos;
 161:  super.flushBefore(pos);
 162:  long flushed = flushedPos - oldPos;
 163:  if (flushed > 0)
 164:  {
 165:  int len = 512;
 166:  byte[] buf = new byte[len];
 167:  cache.seek(oldPos);
 168:  while (flushed > 0)
 169:  {
 170:  int l = (int) Math.min(flushed, len);
 171:  cache.readFully(buf, 0, l);
 172:  stream.write(buf, 0, l);
 173:  flushed -= l;
 174:  }
 175:  stream.flush();
 176:  }
 177:  }
 178: }