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Java > Open Source Codes > alt > jiapi > instrumentor > CombInstrumentor


1 /*
2  * Copyright (C) 2001 Mika Riekkinen, Joni Suominen
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with this library; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  */
18
19 package alt.jiapi.instrumentor;
20
21 import java.math.BigDecimal JavaDoc;
22
23 import org.apache.log4j.Category;
24
25 import alt.jiapi.reflect.InstructionList;
26 import alt.jiapi.Runtime;
27
28 /**
29  * CombInstrumentor keeps track of the instruction lists passing through
30  * it, and forwards some of them according to pattern given to it.
31  *
32  * @author Mika Riekkinen
33  * @author Joni Suominen
34  * @version $Revision: 1.8 $ $Date: 2004/03/15 14:47:53 $
35  */
36 public class CombInstrumentor extends AbstractInstrumentor {
37     private static Category log = Runtime.getLogCategory(CombInstrumentor.class);
38     private long pattern;
39     private long mask = 1;
40
41     /**
42      * Creates CombInstrumentor with given pattern.
43      *
44      * @param pattern
45      */
46     public CombInstrumentor(long pattern) {
47         this.pattern = pattern;
48     }
49
50     public void instrument(InstructionList il) {
51         if ((pattern & mask) == mask) {
52             forward(il);
53         }
54
55         mask = mask << 1;
56
57         if (mask > pattern) { // wrap
58 mask = 1;
59         }
60     }
61 }
62
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