src/be/nikiroo/utils/streams/ReplaceOutputStream.java

   1 package be.nikiroo.utils.streams;
   2
   3 import java.io.IOException;
   4 import java.io.OutputStream;
   5
   6 /**
   7  * This {@link OutputStream} will change some of its content by replacing it
   8  * with something else.
   9  *
  10  * @author niki
  11  */
  12 public class ReplaceOutputStream extends BufferedOutputStream {
  13         private byte[] from;
  14         private byte[] to;
  15
  16         /**
  17          * Create a {@link ReplaceOutputStream} that will replace <tt>from</tt> with
  18          * <tt>to</tt>.
  19          *
  20          * @param out
  21          *            the under-laying {@link OutputStream}
  22          * @param from
  23          *            the {@link String} to replace
  24          * @param to
  25          *            the {@link String} to replace with
  26          */
  27         public ReplaceOutputStream(OutputStream out, String from, String to) {
  28                 this(out, StreamUtils.bytes(from), StreamUtils.bytes(to));
  29         }
  30
  31         /**
  32          * Create a {@link ReplaceOutputStream} that will replace <tt>from</tt> with
  33          * <tt>to</tt>.
  34          *
  35          * @param out
  36          *            the under-laying {@link OutputStream}
  37          * @param from
  38          *            the value to replace
  39          * @param to
  40          *            the value to replace with
  41          */
  42         public ReplaceOutputStream(OutputStream out, byte[] from, byte[] to) {
  43                 super(out);
  44                 bypassFlush = false;
  45
  46                 this.from = from;
  47                 this.to = to;
  48         }
  49
  50         @Override
  51         protected void flush(boolean includingSubStream) throws IOException {
  52                 // Note: very simple, not efficient implementation, sorry.
  53                 while (start < stop) {
  54                         if (from.length > 0
  55                                         && StreamUtils.startsWith(from, buffer, start, stop)) {
  56                                 out.write(to);
  57                                 bytesWritten += to.length;
  58                                 start += from.length;
  59                         } else {
  60                                 out.write(buffer[start++]);
  61                                 bytesWritten++;
  62                         }
  63                 }
  64
  65                 start = 0;
  66                 stop = 0;
  67
  68                 if (includingSubStream) {
  69                         out.flush();
  70                 }
  71         }
  72 }