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18 package org.apache.struts.util;
19
20 import javax.servlet.ServletContext;
21
22 import java.io.PrintWriter;
23 import java.io.StringWriter;
24
25 /***
26 * A PrintWriter implementation that uses the logging facilities of a
27 * <code>javax.servlet.ServletContext</code> to output its results. Output
28 * will be buffered until a newline character is output, <code>flush()</code>
29 * is called, or until one of the <code>println()</code> methods is called.
30 * Along the way, carriage return characters are skipped.
31 *
32 * @version $Rev: 421119 $ $Date: 2005-05-07 12:11:38 -0400 (Sat, 07 May 2005)
33 * $
34 */
35 public class ServletContextWriter extends PrintWriter {
36
37
38 /***
39 * The buffer into which we accumulate lines to be logged.
40 */
41 protected StringBuffer buffer = new StringBuffer();
42
43 /***
44 * The servlet context with which we are associated.
45 */
46 protected ServletContext context = null;
47
48 /***
49 * The error state for this stream.
50 */
51 protected boolean error = false;
52
53
54
55 /***
56 * Construct a ServletContextWriter associated with the specified
57 * ServletContext instance.
58 *
59 * @param context The associated servlet context
60 */
61 public ServletContextWriter(ServletContext context) {
62 super(new StringWriter());
63 this.context = context;
64 }
65
66
67
68 /***
69 * Flush the stream and check for its error state. <strong>IMPLEMENTATION
70 * NOTE</strong> - our associated servlet context gives no indication of
71 * problems with logging, so the only way this method will return
72 * <code>true</code> is if <code>setError()</code> is called.
73 */
74 public boolean checkError() {
75 flush();
76
77 return (error);
78 }
79
80 /***
81 * Close the stream.
82 */
83 public void close() {
84 flush();
85 }
86
87 /***
88 * Flush the stream.
89 */
90 public void flush() {
91 if (buffer.length() > 0) {
92 context.log(buffer.toString());
93 buffer.setLength(0);
94 }
95 }
96
97 /***
98 * Print a boolean value.
99 *
100 * @param b The value to be printed
101 */
102 public void print(boolean b) {
103 write(String.valueOf(b));
104 }
105
106 /***
107 * Print a character value.
108 *
109 * @param c The value to be printed
110 */
111 public void print(char c) {
112 write(c);
113 }
114
115 /***
116 * Print a character array.
117 *
118 * @param c The character array to be printed
119 */
120 public void print(char[] c) {
121 for (int i = 0; i < c.length; i++) {
122 write(c[i]);
123 }
124 }
125
126 /***
127 * Print a double value.
128 *
129 * @param d The value to be printed
130 */
131 public void print(double d) {
132 write(String.valueOf(d));
133 }
134
135 /***
136 * Print a float value.
137 *
138 * @param f The value to be printed
139 */
140 public void print(float f) {
141 write(String.valueOf(f));
142 }
143
144 /***
145 * Print an integer value.
146 *
147 * @param i The value to be printed
148 */
149 public void print(int i) {
150 write(String.valueOf(i));
151 }
152
153 /***
154 * Print a long value.
155 *
156 * @param l The value to be printed
157 */
158 public void print(long l) {
159 write(String.valueOf(l));
160 }
161
162 /***
163 * Print an object.
164 *
165 * @param o The value to be printed
166 */
167 public void print(Object o) {
168 write(o.toString());
169 }
170
171 /***
172 * Print a String value.
173 *
174 * @param s The value to be printed
175 */
176 public void print(String s) {
177 int len = s.length();
178
179 for (int i = 0; i < len; i++) {
180 write(s.charAt(i));
181 }
182 }
183
184 /***
185 * Terminate the current line and flush the buffer.
186 */
187 public void println() {
188 flush();
189 }
190
191 /***
192 * Print a boolean value and terminate the line.
193 *
194 * @param b The value to be printed
195 */
196 public void println(boolean b) {
197 println(String.valueOf(b));
198 }
199
200 /***
201 * Print a character value and terminate the line.
202 *
203 * @param c The value to be printed
204 */
205 public void println(char c) {
206 write(c);
207 println();
208 }
209
210 /***
211 * Print a character array and terminate the line.
212 *
213 * @param c The character array to be printed
214 */
215 public void println(char[] c) {
216 for (int i = 0; i < c.length; i++) {
217 print(c[i]);
218 }
219
220 println();
221 }
222
223 /***
224 * Print a double value and terminate the line.
225 *
226 * @param d The value to be printed
227 */
228 public void println(double d) {
229 println(String.valueOf(d));
230 }
231
232 /***
233 * Print a float value and terminate the line.
234 *
235 * @param f The value to be printed
236 */
237 public void println(float f) {
238 println(String.valueOf(f));
239 }
240
241 /***
242 * Print an integer value and terminate the line.
243 *
244 * @param i The value to be printed
245 */
246 public void println(int i) {
247 println(String.valueOf(i));
248 }
249
250 /***
251 * Print a long value and terminate the line.
252 *
253 * @param l The value to be printed
254 */
255 public void println(long l) {
256 println(String.valueOf(l));
257 }
258
259 /***
260 * Print an object and terminate the line.
261 *
262 * @param o The value to be printed
263 */
264 public void println(Object o) {
265 println(o.toString());
266 }
267
268 /***
269 * Print a String value and terminate the line.
270 *
271 * @param s The value to be printed
272 */
273 public void println(String s) {
274 int len = s.length();
275
276 for (int i = 0; i < len; i++) {
277 print(s.charAt(i));
278 }
279
280 println();
281 }
282
283 /***
284 * Set the error state for this stream.
285 */
286 public void setError() {
287 this.error = true;
288 }
289
290 /***
291 * Write a single character to this stream.
292 *
293 * @param c The character to be written
294 */
295 public void write(char c) {
296 if (c == '\n') {
297 flush();
298 } else if (c != '\r') {
299 buffer.append(c);
300 }
301 }
302
303 /***
304 * Write a single character to this stream.
305 *
306 * @param c The character to be written
307 */
308 public void write(int c) {
309 write((char) c);
310 }
311
312 /***
313 * Write an array of charaters to this stream.
314 *
315 * @param buf The character array to be written
316 */
317 public void write(char[] buf) {
318 for (int i = 0; i < buf.length; i++) {
319 write(buf[i]);
320 }
321 }
322
323 /***
324 * Write the specified subset of an array of characters to this stream.
325 *
326 * @param buf The character array from which to write
327 * @param off The zero-relative starting offset to write
328 * @param len The number of characters to write
329 */
330 public void write(char[] buf, int off, int len) {
331 for (int i = off; i < len; i++) {
332 write(buf[i]);
333 }
334 }
335
336 /***
337 * Write a String to this stream.
338 *
339 * @param s The string to be written
340 */
341 public void write(String s) {
342 int len = s.length();
343
344 for (int i = 0; i < len; i++) {
345 write(s.charAt(i));
346 }
347 }
348
349 /***
350 * Write the specified portion of a String to this stream.
351 *
352 * @param s The String from which to write
353 * @param off The zero-relative starting offset to write
354 * @param len The number of characters to write
355 */
356 public void write(String s, int off, int len) {
357 for (int i = off; i < len; i++) {
358 write(s.charAt(i));
359 }
360 }
361 }