1 // ========================================================================
2 // Copyright (c) 2006-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13
14 package org.eclipse.jetty.util;
15
16 /* ------------------------------------------------------------ */
17 /**
18 * UTF-8 StringBuffer.
19 *
20 * This class wraps a standard {@link java.lang.StringBuffer} and provides methods to append
21 * UTF-8 encoded bytes, that are converted into characters.
22 *
23 * This class is stateful and up to 4 calls to {@link #append(byte)} may be needed before
24 * state a character is appended to the string buffer.
25 *
26 * The UTF-8 decoding is done by this class and no additional buffers or Readers are used.
27 * The UTF-8 code was inspired by http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
28 */
29 public class Utf8StringBuffer extends Utf8Appendable
30 {
31 final StringBuffer _buffer;
32
33 public Utf8StringBuffer()
34 {
35 super(new StringBuffer());
36 _buffer = (StringBuffer)_appendable;
37 }
38
39 public Utf8StringBuffer(int capacity)
40 {
41 super(new StringBuffer(capacity));
42 _buffer = (StringBuffer)_appendable;
43 }
44
45 @Override
46 public int length()
47 {
48 return _buffer.length();
49 }
50
51 @Override
52 public void reset()
53 {
54 super.reset();
55 _buffer.setLength(0);
56 }
57
58 public StringBuffer getStringBuffer()
59 {
60 checkState();
61 return _buffer;
62 }
63
64 @Override
65 public String toString()
66 {
67 checkState();
68 return _buffer.toString();
69 }
70
71 private void checkState()
72 {
73 if (!isUtf8SequenceComplete())
74 throw new IllegalArgumentException("Tried to read incomplete UTF8 decoded String");
75 }
76 }