CheckedOutputStream


1   /*
2    * @(#)CheckedOutputStream.java 1.18 03/12/19
3    *
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   package java.util.zip;
9   
10  import java.io.FilterOutputStream  ;
11  import java.io.OutputStream  ;
12  import java.io.IOException  ;
13  
14  /**
15   * An output stream that also maintains a checksum of the data being
16   * written. The checksum can then be used to verify the integrity of
17   * the output data.
18   *
19   * @see     Checksum
20   * @version     1.18, 12/19/03
21   * @author  David Connelly
22   */
23  public
24  class CheckedOutputStream extends FilterOutputStream   {
25      private Checksum   cksum;
26  
27      /**
28       * Creates an output stream with the specified Checksum.
29       * @param out the output stream
30       * @param cksum the checksum
31       */
32      public CheckedOutputStream(OutputStream   out, Checksum   cksum) {
33      super(out);
34      this.cksum = cksum;
35      }
36  
37      /**
38       * Writes a byte. Will block until the byte is actually written.
39       * @param b the byte to be written
40       * @exception IOException if an I/O error has occurred
41       */
42      public void write(int b) throws IOException   {
43      out.write(b);
44      cksum.update(b);
45      }
46  
47      /**
48       * Writes an array of bytes. Will block until the bytes are
49       * actually written.
50       * @param b the data to be written
51       * @param off the start offset of the data
52       * @param len the number of bytes to be written
53       * @exception IOException if an I/O error has occurred
54       */
55      public void write(byte[] b, int off, int len) throws IOException   {
56      out.write(b, off, len);
57      cksum.update(b, off, len);
58      }
59  
60      /**
61       * Returns the Checksum for this output stream.
62       * @return the Checksum
63       */
64      public Checksum   getChecksum() {
65      return cksum;
66      }
67  }
68
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