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1
23
24
29
30 package com.sun.appserv.management.util.misc;
31
32 import java.text.StringCharacterIterator  ;
33
34
35
38 public final class StringEscaper
39 {
40 static final public char BACKSLASH = '\\';
41 static final public char NEWLINE = '\n';
42 static final public char RETURN = '\r';
43 static final public char TAB = '\t';
44 static final public char SPACE = ' ';
45
46 static final public char ESCAPE_CHAR = BACKSLASH;
47 static final public char UNICODE_START = 'u';
48 final char mEscapeChar;
49 final char[] mCharsToEscape;
50 StringCharacterIterator mCharIter;
51
52 public
53 StringEscaper()
54 {
55 this( "\n\r\t" );
56 }
57
58 public
59 StringEscaper( String charsToEscape )
60 {
61 this( ESCAPE_CHAR, charsToEscape );
62 }
63
64
65 public
66 StringEscaper( char escapeChar, String charsToEscape )
67 {
68 mCharIter = null;
69
70 mEscapeChar = escapeChar;
71
72 mCharsToEscape = new char[ 1 + charsToEscape.length() ];
73
74 mCharsToEscape[ 0 ] = ESCAPE_CHAR;
75 final int length = charsToEscape.length();
76 for( int i = 0; i < length; ++i )
77 {
78 mCharsToEscape[ i + 1 ] = charsToEscape.charAt( i );
79 }
80 }
81
82 boolean
83 shouldEscape( final char c )
84 {
85 boolean shouldEscape = false;
86
87 for( int i = 0; i < mCharsToEscape.length; ++i )
88 {
89 if ( c == mCharsToEscape[ i ] )
90 {
91 shouldEscape = true;
92 break;
93 }
94 }
95
96 return( shouldEscape );
97 }
98
99
102 String
103 getEscapeSequence( char c )
104 {
105 String sequence = null;
106
107 if ( c == mEscapeChar )
108 {
109 sequence = "" + mEscapeChar + mEscapeChar;
110 }
111 else if ( c == NEWLINE )
112 {
113 sequence = mEscapeChar + "n";
114 }
115 else if ( c == RETURN )
116 {
117 sequence = mEscapeChar + "r";
118 }
119 else if ( c == TAB )
120 {
121 sequence = mEscapeChar + "t";
122 }
123 else if ( c == SPACE )
124 {
125 sequence = mEscapeChar + "s";
126 }
127 else
128 {
129 final int numericValue = (int)c;
130
131 String valueString = "" + Integer.toHexString( numericValue );
132 while ( valueString.length() != 4 )
134 {
135 valueString = "0" + valueString;
136 }
137
138 sequence = mEscapeChar + (UNICODE_START + valueString);
140 }
141
142 return( sequence );
143 }
144
145 public String
146 escape( String s)
147 {
148 final StringBuffer buf = new StringBuffer ();
149
150 final int length = s.length();
151 for( int i = 0; i < length; ++i )
152 {
153 final char c = s.charAt( i );
154
155 if ( shouldEscape( c ) )
156 {
157 buf.append( getEscapeSequence( c ) );
158 }
159 else
160 {
161 buf.append( c );
162 }
163 }
164
165 return( buf.toString() );
166 }
167
168 boolean
169 hasMoreChars()
170 {
171 return( mCharIter.current() != mCharIter.DONE );
172 }
173
174 char
175 peekNextChar()
176 {
177 return( mCharIter.current() );
178 }
179
180 char
181 nextChar()
182 {
183 final char theChar = mCharIter.current();
184 mCharIter.next();
185
186 if ( theChar == mCharIter.DONE )
187 {
188 throw new ArrayIndexOutOfBoundsException ();
189 }
190
191 return( theChar );
192 }
193
194 char
195 escapeSequenceToChar()
196 {
197 final char c = nextChar();
198 char result = 0;
199
200 if ( c == mEscapeChar )
201 {
202 result = mEscapeChar;
203 }
204 else if ( c == 'n' )
205 {
206 result = NEWLINE;
207 }
208 else if ( c == 'r' )
209 {
210 result = RETURN;
211 }
212 else if ( c == 't' )
213 {
214 result = TAB;
215 }
216 else if ( c == 's' )
217 {
218 result = SPACE;
219 }
220 else if ( c == UNICODE_START )
221 {
222 final String unicodeSequence = "" + nextChar() + nextChar() + nextChar() + nextChar();
223 final int intValue = Integer.parseInt( unicodeSequence, 16 );
224
225 result = (char)intValue;
226 }
227 else
228 {
229 throw new IllegalArgumentException ( "Illegal escape sequence" );
230 }
231
232 return( result );
233 }
234
235
236 public String
237 unescape( String s )
238 {
239 final StringBuffer buf = new StringBuffer ();
240
241 mCharIter = new StringCharacterIterator ( s );
242
243 while ( hasMoreChars() )
244 {
245 final char c = (char)nextChar();
246 assert ( c != mCharIter.DONE );
247
248 if ( c == mEscapeChar )
249 {
250 final char newChar = escapeSequenceToChar();
251 buf.append( newChar );
252 }
253 else
254 {
255 buf.append( c );
256 }
257 }
258
259 mCharIter = null;
260
261 return( buf.toString() );
262 }
263 }
264
265 |
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