1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.tomcat.util.log;
19
20 import java.io.IOException;
21 import java.io.PrintStream;
22 import java.util.EmptyStackException;
23 import java.util.Stack;
24
25 /**
26 * This helper class may be used to do sophisticated redirection of
27 * System.out and System.err on a per Thread basis.
28 *
29 * A stack is implemented per Thread so that nested startCapture
30 * and stopCapture can be used.
31 *
32 * @author Remy Maucherat
33 * @author Glenn L. Nielsen
34 */
35 public class SystemLogHandler extends PrintStream {
36
37
38 // ----------------------------------------------------------- Constructors
39
40
41 /**
42 * Construct the handler to capture the output of the given steam.
43 */
44 public SystemLogHandler(PrintStream wrapped) {
45 super(wrapped);
46 out = wrapped;
47 }
48
49
50 // ----------------------------------------------------- Instance Variables
51
52
53 /**
54 * Wrapped PrintStream.
55 */
56 protected PrintStream out = null;
57
58
59 /**
60 * Thread <-> CaptureLog associations.
61 */
62 protected static ThreadLocal logs = new ThreadLocal();
63
64
65 /**
66 * Spare CaptureLog ready for reuse.
67 */
68 protected static Stack reuse = new Stack();
69
70
71 // --------------------------------------------------------- Public Methods
72
73
74 /**
75 * Start capturing thread's output.
76 */
77 public static void startCapture() {
78 CaptureLog log = null;
79 if (!reuse.isEmpty()) {
80 try {
81 log = (CaptureLog)reuse.pop();
82 } catch (EmptyStackException e) {
83 log = new CaptureLog();
84 }
85 } else {
86 log = new CaptureLog();
87 }
88 Stack stack = (Stack)logs.get();
89 if (stack == null) {
90 stack = new Stack();
91 logs.set(stack);
92 }
93 stack.push(log);
94 }
95
96
97 /**
98 * Stop capturing thread's output and return captured data as a String.
99 */
100 public static String stopCapture() {
101 Stack stack = (Stack)logs.get();
102 if (stack == null || stack.isEmpty()) {
103 return null;
104 }
105 CaptureLog log = (CaptureLog)stack.pop();
106 if (log == null) {
107 return null;
108 }
109 String capture = log.getCapture();
110 log.reset();
111 reuse.push(log);
112 return capture;
113 }
114
115
116 // ------------------------------------------------------ Protected Methods
117
118
119 /**
120 * Find PrintStream to which the output must be written to.
121 */
122 protected PrintStream findStream() {
123 Stack stack = (Stack)logs.get();
124 if (stack != null && !stack.isEmpty()) {
125 CaptureLog log = (CaptureLog)stack.peek();
126 if (log != null) {
127 PrintStream ps = log.getStream();
128 if (ps != null) {
129 return ps;
130 }
131 }
132 }
133 return out;
134 }
135
136
137 // ---------------------------------------------------- PrintStream Methods
138
139
140 public void flush() {
141 findStream().flush();
142 }
143
144 public void close() {
145 findStream().close();
146 }
147
148 public boolean checkError() {
149 return findStream().checkError();
150 }
151
152 protected void setError() {
153 //findStream().setError();
154 }
155
156 public void write(int b) {
157 findStream().write(b);
158 }
159
160 public void write(byte[] b)
161 throws IOException {
162 findStream().write(b);
163 }
164
165 public void write(byte[] buf, int off, int len) {
166 findStream().write(buf, off, len);
167 }
168
169 public void print(boolean b) {
170 findStream().print(b);
171 }
172
173 public void print(char c) {
174 findStream().print(c);
175 }
176
177 public void print(int i) {
178 findStream().print(i);
179 }
180
181 public void print(long l) {
182 findStream().print(l);
183 }
184
185 public void print(float f) {
186 findStream().print(f);
187 }
188
189 public void print(double d) {
190 findStream().print(d);
191 }
192
193 public void print(char[] s) {
194 findStream().print(s);
195 }
196
197 public void print(String s) {
198 findStream().print(s);
199 }
200
201 public void print(Object obj) {
202 findStream().print(obj);
203 }
204
205 public void println() {
206 findStream().println();
207 }
208
209 public void println(boolean x) {
210 findStream().println(x);
211 }
212
213 public void println(char x) {
214 findStream().println(x);
215 }
216
217 public void println(int x) {
218 findStream().println(x);
219 }
220
221 public void println(long x) {
222 findStream().println(x);
223 }
224
225 public void println(float x) {
226 findStream().println(x);
227 }
228
229 public void println(double x) {
230 findStream().println(x);
231 }
232
233 public void println(char[] x) {
234 findStream().println(x);
235 }
236
237 public void println(String x) {
238 findStream().println(x);
239 }
240
241 public void println(Object x) {
242 findStream().println(x);
243 }
244
245 }