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1
55 package org.apache.log.format;
56
57 import java.io.PrintWriter  ;
58 import java.io.StringWriter ;
59 import java.lang.reflect.Method ;
60 import java.util.StringTokenizer ;
61
62
72 final class ExceptionUtil
73 {
74 private static final String LINE_SEPARATOR = System.getProperty( "line.separator" );
75 private static final String GET_CAUSE_NAME = "getCause";
76 private static final Class [] GET_CAUSE_PARAMTYPES = new Class [ 0 ];
77 private static final Class CASCADING_INTERFACE;
78
79 static
80 {
81 Class klass = null;
82 try
83 {
84 klass = Class.forName("org.apache.avalon.framework.CascadingThrowable");
85 }
86 catch (Exception e)
87 {
88 klass = null;
90 }
91
92 CASCADING_INTERFACE = klass;
93 }
94
95
98 private ExceptionUtil()
99 {
100 }
101
102
108 public static String printStackTrace( final Throwable throwable )
109 {
110 return printStackTrace( throwable, 0, true );
111 }
112
113
120 public static String printStackTrace( final Throwable throwable,
121 final boolean printCascading )
122 {
123 return printStackTrace( throwable, 0, printCascading );
124 }
125
126
135 public static String printStackTrace( final Throwable throwable, final int depth )
136 {
137 int dp = depth;
138 final String [] lines = captureStackTrace( throwable );
139
140 if( 0 == dp || dp > lines.length )
141 {
142 dp = lines.length;
143 }
144
145 final StringBuffer sb = new StringBuffer ();
146
147 for( int i = 0; i < dp; i++ )
148 {
149 sb.append( lines[ i ] );
150 sb.append( LINE_SEPARATOR );
151 }
152
153 return sb.toString();
154 }
155
156
164 public static String printStackTrace( final Throwable throwable,
165 final int depth,
166 final boolean printCascading )
167 {
168 return printStackTrace( throwable, depth, printCascading, true );
169 }
170
171
184 public static String printStackTrace( final Throwable throwable,
185 final int depth,
186 final boolean printCascading,
187 final boolean useReflection )
188 {
189 final String result = printStackTrace( throwable, depth );
190
191 if( !printCascading )
192 {
193 return result;
194 }
195 else
196 {
197 final StringBuffer sb = new StringBuffer ();
198 sb.append( result );
199
200 Throwable cause = getCause( throwable, useReflection );
201
202 while( null != cause )
203 {
204 sb.append( "rethrown from" );
205 sb.append( LINE_SEPARATOR );
206 sb.append( printStackTrace( cause, depth ) );
207
208 cause = getCause( cause, useReflection );
209 }
210
211 return sb.toString();
212 }
213 }
214
215
222 public static Throwable getCause( final Throwable throwable,
223 final boolean useReflection )
224 {
225 if( useReflection ||
226 ( null != CASCADING_INTERFACE &&
227 CASCADING_INTERFACE.isAssignableFrom(throwable.getClass()) ) )
228 {
229 try
230 {
231 final Class clazz = throwable.getClass();
232 final Method method =
233 clazz.getMethod( GET_CAUSE_NAME, GET_CAUSE_PARAMTYPES );
234 return (Throwable )method.invoke( throwable, null );
235 }
236 catch( final Throwable t )
237 {
238 return null;
239 }
240 }
241 else
242 {
243 return null;
244 }
245 }
246
247
253 public static String [] captureStackTrace( final Throwable throwable )
254 {
255 final StringWriter sw = new StringWriter ();
256 throwable.printStackTrace( new PrintWriter ( sw, true ) );
257 return splitStringInternal( sw.toString(), LINE_SEPARATOR );
258 }
259
260
268 public static String [] splitString( final String string, final String onToken )
269 {
270 return splitStringInternal( string, onToken );
271 }
272
273
280 private static String [] splitStringInternal( final String string, final String onToken )
281 {
282 final StringTokenizer tokenizer = new StringTokenizer ( string, onToken );
283 final String [] result = new String [ tokenizer.countTokens() ];
284
285 for( int i = 0; i < result.length; i++ )
286 {
287 result[ i ] = tokenizer.nextToken();
288 }
289
290 return result;
291 }
292 }
293 |
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