01: /*
02: * FindBugs - Find bugs in Java programs
03: * Copyright (C) 2004-2006 University of Maryland
04: *
05: * This library is free software; you can redistribute it and/or
06: * modify it under the terms of the GNU Lesser General Public
07: * License as published by the Free Software Foundation; either
08: * version 2.1 of the License, or (at your option) any later version.
09: *
10: * This library is distributed in the hope that it will be useful,
11: * but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13: * Lesser General Public License for more details.
14: *
15: * You should have received a copy of the GNU Lesser General Public
16: * License along with this library; if not, write to the Free Software
17: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18: */
19:
20: package edu.umd.cs.findbugs.bcel;
21:
22: import org.apache.bcel.classfile.Code;
23:
24: import edu.umd.cs.findbugs.BytecodeScanningDetector;
25: import edu.umd.cs.findbugs.OpcodeStack;
26:
27: /**
28: * Base class for Detectors that want to scan the bytecode
29: * of a method and use an opcode stack.
30: *
31: * @see BytecodeScanningDetector
32: */
33: abstract public class OpcodeStackDetector extends
34: BytecodeScanningDetector {
35:
36: protected OpcodeStack stack;
37:
38: @Override
39: public void visit(Code obj) {
40: stack = new OpcodeStack();
41: stack.resetForMethodEntry(this );
42: super .visit(obj);
43: }
44:
45: @Override
46: public boolean beforeOpcode(int seen) {
47: stack.mergeJumps(this );
48: return !stack.isTop();
49: }
50:
51: @Override
52: public void afterOpcode(int seen) {
53: stack.sawOpcode(this , seen);
54: }
55:
56: @Override
57: abstract public void sawOpcode(int seen);
58: }
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