01: /*
02: *
03: *
04: * Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
05: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License version
09: * 2 only, as published by the Free Software Foundation.
10: *
11: * This program is distributed in the hope that it will be useful, but
12: * WITHOUT ANY WARRANTY; without even the implied warranty of
13: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14: * General Public License version 2 for more details (a copy is
15: * included at /legal/license.txt).
16: *
17: * You should have received a copy of the GNU General Public License
18: * version 2 along with this work; if not, write to the Free Software
19: * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20: * 02110-1301 USA
21: *
22: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
23: * Clara, CA 95054 or visit www.sun.com if you need additional
24: * information or have any questions.
25: */
26:
27: package com.sun.cldchi.jvm;
28:
29: /**
30: * Java API to support run-time method trapping from Java code.
31: * It is used internally by J2ME software stack implementations
32: * and should be placed in a hidden package.
33: * MethodTrap class allows to change execution entry of Java methods.
34: */
35: public final class MethodTrap {
36:
37: /** Invoke callback function */
38: public static final int ACTION_CALLBACK = 0;
39: /** Causes JVM to stop */
40: public static final int ACTION_EXIT = -1;
41: /** Causes current isolate to stop */
42: public static final int ACTION_STOP_ISOLATE = -2;
43: /** Causes native breakpoint to happen */
44: public static final int ACTION_BREAKPOINT = -3;
45:
46: /**
47: * Trap specified Java method for JVM to take special action before
48: * the method is invoked.
49: * @param methodName - fully-qualified name of the method to trap,
50: * looks like package.ClassName.methodName
51: * @param callCount - take an action only when the method is called
52: * callCount times
53: * @param action - the code of the action for JVM to take
54: * on the method invocation, can be
55: * one of ACTION_*
56: * @param targetTask - id of a task that should be stopped on the method call,
57: * method with the same from other tasks won't be trapped.
58: * 0 means any task will match
59: *
60: * @return trapHandle - unique identifier of the trap that can be passed
61: * to subsequent repeaseTrap() call
62: */
63: public static native int setTrap(String methodName, int callCount,
64: int action, int targetTask);
65:
66: /**
67: * Replace the execution entry of the specified method with
68: * the execution entry of another method with the similar signature.
69: * @param methodName - fully-qualified name of the method to trap,
70: * looks like package.ClassName.methodName
71: * @param handlerName - fully-qualified name of the method to be invoked
72: * instead of the trapped method. The handler must
73: * have the same parameter types as the original
74: * method.
75: */
76: public static native int setJavaTrap(String methodName,
77: String handlerName);
78:
79: /**
80: * Release Java method that was previously trapped by setTrap() call.
81: * @param trapHandle - the identifier of the trap that was returned
82: * by previous call to setTrap() or setJavaTrap()
83: */
84: public static native void releaseTrap(int trapHandle);
85:
86: }
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