1 cananian 1.1.2.1 // Counters.java, created Thu Feb 22 21:48:58 2001 by cananian
2 cananian 1.1.2.1 // Copyright (C) 2000 C. Scott Ananian <cananian@alumni.princeton.edu>
3 cananian 1.1.2.1 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 cananian 1.1.2.1 package harpoon.Runtime;
5 cananian 1.1.2.1
6 cananian 1.1.2.1 import java.lang.reflect.Field;
7 cananian 1.1.2.1 /**
8 cananian 1.1.2.1 * <code>Counters</code> uses reflection to provide a very light-weight
9 cananian 1.1.2.1 * counter package -- light-weight in terms of FLEX code required to
10 cananian 1.1.2.1 * add/enable counters, not necessarily light-weight in terms of
11 cananian 1.1.2.1 * execution time. All counters are thread-safe. We use reflection
12 cananian 1.1.2.1 * at initialization time and at program termination to initialize
13 cananian 1.1.2.1 * and report counter values, which minimizes the amount of
14 cananian 1.1.2.1 * counter-specific code generation required by the FLEX side of
15 cananian 1.1.2.1 * this. No special runtime support is required.
16 cananian 1.1.2.1 * <p>
17 cananian 1.1.2.1 * The dynamic generation of counter fields in this class is
18 cananian 1.1.2.1 * handled by <code>harpoon.Analysis.Counters.CounterFactory</code>.
19 cananian 1.1.2.3 * There is a <code>HCodeFactory</code> in this class which must be
20 cananian 1.1.2.3 * included as a compilation pass to generate the proper calls to
21 cananian 1.1.2.3 * the <code>report()</code> method at program's end.
22 cananian 1.1.2.1 *
23 cananian 1.1.2.1 * @author C. Scott Ananian <cananian@alumni.princeton.edu>
24 cananian 1.2 * @version $Id: Counters.java,v 1.2 2002/02/25 21:06:26 cananian Exp $
25 cananian 1.1.2.1 */
26 cananian 1.1.2.1 public class Counters {
27 cananian 1.1.2.2 // hide constructor. all fields/methods are static.
28 cananian 1.1.2.2 private Counters() { }
29 cananian 1.1.2.1 /** Initialize by using reflection to store new <code>Object</code>s in
30 cananian 1.1.2.1 * all (FLEX-generated) fields of this class with names starting
31 cananian 1.1.2.1 * with "LOCK_".
32 cananian 1.1.2.1 */
33 cananian 1.1.2.1 static {
34 cananian 1.1.2.1 Field[] field = Counters.class.getDeclaredFields();
35 cananian 1.1.2.1 for (int i=0; i<field.length; i++)
36 cananian 1.1.2.1 if (field[i].getName().startsWith("LOCK_"))
37 cananian 1.1.2.1 try {
38 cananian 1.1.2.1 field[i].set(null, new Object());
39 cananian 1.1.2.1 } catch (IllegalAccessException e) {
40 cananian 1.1.2.4 System.err.println("SKIPPING INIT OF "+field[i].toString());
41 cananian 1.1.2.1 }
42 cananian 1.1.2.1 }
43 cananian 1.1.2.1
44 cananian 1.1.2.1 /** Report counter values to <code>System.err</code>, using reflection
45 cananian 1.1.2.1 * to discover all fields starting with "COUNTER_". */
46 cananian 1.1.2.1 public static void report() {
47 cananian 1.1.2.1 Field[] field = Counters.class.getDeclaredFields();
48 cananian 1.1.2.1 for (int i=0; i<field.length; i++)
49 cananian 1.1.2.1 if (field[i].getName().startsWith("COUNTER_"))
50 cananian 1.1.2.1 try {
51 cananian 1.1.2.1 String name = field[i].getName().substring(8);
52 cananian 1.1.2.1 Field Flck = Counters.class.getDeclaredField("LOCK_"+name);
53 cananian 1.1.2.1 synchronized(Flck.get(null)) {
54 cananian 1.1.2.4 System.err.println(name+": "+
55 cananian 1.1.2.4 ((Number)field[i].get(null))
56 cananian 1.1.2.4 .longValue());
57 cananian 1.1.2.1 }
58 cananian 1.1.2.1 } catch (NoSuchFieldException e) {
59 cananian 1.1.2.4 System.err.println("CAN'T FIND FIELD: "+e.toString());
60 cananian 1.1.2.1 } catch (IllegalAccessException e) {
61 cananian 1.1.2.4 System.err.println("CAN'T READ FIELD: "+e.toString());
62 cananian 1.1.2.1 }
63 cananian 1.1.2.1 }
64 cananian 1.2 }