01: /***
02: * ASM Guide
03: * Copyright (c) 2007 Eric Bruneton
04: * All rights reserved.
05: *
06: * Redistribution and use in source and binary forms, with or without
07: * modification, are permitted provided that the following conditions
08: * are met:
09: * 1. Redistributions of source code must retain the above copyright
10: * notice, this list of conditions and the following disclaimer.
11: * 2. Redistributions in binary form must reproduce the above copyright
12: * notice, this list of conditions and the following disclaimer in the
13: * documentation and/or other materials provided with the distribution.
14: * 3. Neither the name of the copyright holders nor the names of its
15: * contributors may be used to endorse or promote products derived from
16: * this software without specific prior written permission.
17: *
18: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28: * THE POSSIBILITY OF SUCH DAMAGE.
29: */package ch7.sec2;
30:
31: import static org.objectweb.asm.Opcodes.CHECKCAST;
32:
33: import org.objectweb.asm.MethodAdapter;
34: import org.objectweb.asm.MethodVisitor;
35: import org.objectweb.asm.commons.AnalyzerAdapter;
36:
37: /**
38: * ASM Guide example class.
39: *
40: * @author Eric Bruneton
41: */
42: public class RemoveUnusedCastAdapter extends MethodAdapter {
43:
44: public AnalyzerAdapter aa;
45:
46: public RemoveUnusedCastAdapter(MethodVisitor mv) {
47: super (mv);
48: }
49:
50: public void visitTypeInsn(int opcode, String desc) {
51: if (opcode == CHECKCAST) {
52: Class to = getClass(desc);
53: if (aa.stack != null && aa.stack.size() > 0) {
54: Object operand = aa.stack.get(aa.stack.size() - 1);
55: if (operand instanceof String) {
56: Class from = getClass((String) operand);
57: if (to.isAssignableFrom(from)) {
58: return;
59: }
60: }
61: }
62: }
63: mv.visitTypeInsn(opcode, desc);
64: }
65:
66: private static Class getClass(String desc) {
67: try {
68: return Class.forName(desc.replace('/', '.'));
69: } catch (ClassNotFoundException e) {
70: throw new RuntimeException(e.toString());
71: }
72: }
73: }
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