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1
18 package org.apache.beehive.netui.util.internal;
19
20 import java.io.Serializable  ;
21
22
23
26 public final class InternalStringBuilder
27 implements Serializable
28 {
29 private char _buffer[];
30 private int _length = 0;
31 private boolean _shared;
32
33 static final long serialVersionUID = 1;
34
35 public InternalStringBuilder()
36 {
37 this( 16 );
38 }
39
40 public InternalStringBuilder( int length )
41 {
42 _buffer = new char[length];
43 _shared = false;
44 }
45
46 public InternalStringBuilder( String str )
47 {
48 this( str.length() + 16 );
49 append( str );
50 }
51
52 public int length()
53 {
54 return _length;
55 }
56
57 private final void copyWhenShared()
58 {
59 if ( _shared )
60 {
61 char newValue[] = new char[_buffer.length];
62 System.arraycopy( _buffer, 0, newValue, 0, _length );
63 _buffer = newValue;
64 _shared = false;
65 }
66 }
67
68 public void ensureCapacity( int minCapacity )
69 {
70 int maxCapacity = _buffer.length;
71
72 if ( minCapacity > maxCapacity )
73 {
74 int newCapacity = ( maxCapacity + 1 ) * 2;
75 if ( minCapacity > newCapacity ) newCapacity = minCapacity;
76 char newValue[] = new char[newCapacity];
77 System.arraycopy( _buffer, 0, newValue, 0, _length );
78 _buffer = newValue;
79 _shared = false;
80 }
81 }
82
83 public void setLength( int length )
84 {
85 if ( length < 0 ) throw new StringIndexOutOfBoundsException ( length );
86 ensureCapacity( length );
87
88 if ( _length < length )
89 {
90 copyWhenShared();
91 while ( _length < length )
92 {
93 _buffer[_length++] = '\0';
94 }
95 }
96 _length = length;
97 }
98
99 public char charAt( int index )
100 {
101 if ( index < 0 || index >= _length ) throw new StringIndexOutOfBoundsException ( index );
102 return _buffer[index];
103 }
104
105 public InternalStringBuilder append( Object obj )
106 {
107 return append( String.valueOf( obj ) );
108 }
109
110 public InternalStringBuilder append( String str )
111 {
112 if ( str == null ) str = String.valueOf( str );
113 int len = str.length();
114 ensureCapacity( _length + len );
115 copyWhenShared();
116 str.getChars( 0, len, _buffer, _length );
117 _length += len;
118 return this;
119 }
120
121 public InternalStringBuilder append( char c )
122 {
123 ensureCapacity( _length + 1 );
124 copyWhenShared();
125 _buffer[_length++] = c;
126 return this;
127 }
128
129 public InternalStringBuilder append( int i )
130 {
131 return append( String.valueOf( i ) );
132 }
133
134 public String toString()
135 {
136 _shared = true;
137 return new String ( _buffer, 0, _length );
138 }
139
140 public InternalStringBuilder deleteCharAt( int index )
141 {
142 if ( index < 0 || index >= _length ) throw new StringIndexOutOfBoundsException ( index );
143 System.arraycopy( _buffer, index + 1, _buffer, index, _length - index - 1 );
144 _length--;
145 return this;
146 }
147 }
148 |
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