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17 package org.apache.log4j;
18
19 import junit.framework.Assert;
20
21 import org.apache.log4j.Level;
22 import org.apache.log4j.Logger;
23 import org.apache.log4j.VectorAppender;
24 import org.apache.log4j.spi.LoggingEvent;
25
26 import java.util.Vector;
27
28
29 /***
30 * Helper class to set up and capture log messages.
31 */
32 public class LogCapture {
33 /***
34 * Appender.
35 */
36 private final VectorAppender appender;
37
38 /***
39 * Expected level.
40 */
41 private final Level level;
42
43 /***
44 * Creates new instance of LogCapture.
45 *
46 */
47 public LogCapture(final Level level) {
48 this.level = level;
49
50 Logger root = Logger.getRootLogger();
51 appender = new VectorAppender();
52 root.addAppender(appender);
53 }
54
55 /***
56 * Get message.
57 * @return rendered message, null if no logging event captured.
58 */
59 public String getMessage() {
60 Vector vector = appender.getVector();
61 String msg = null;
62
63 switch (vector.size()) {
64 case 0:
65 break;
66
67 case 1:
68
69 LoggingEvent event = (LoggingEvent) vector.elementAt(0);
70 Assert.assertNotNull(event);
71 Assert.assertEquals(level, event.getLevel());
72 msg = event.getRenderedMessage();
73
74 break;
75
76 default:
77 Assert.fail("More than one request captured");
78 }
79
80 return msg;
81 }
82 }