01: /*
02: * Bytecode Analysis Framework
03: * Copyright (C) 2003,2004 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.ba.bcp;
21:
22: import org.apache.bcel.generic.ConstantPoolGen;
23: import org.apache.bcel.generic.Instruction;
24: import org.apache.bcel.generic.InstructionHandle;
25: import org.apache.bcel.generic.MONITORENTER;
26:
27: import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
28: import edu.umd.cs.findbugs.ba.vna.ValueNumberFrame;
29:
30: /**
31: * A PatternElement for matching a MONITORENTER instruction.
32: *
33: * @author DavidHovemeyer
34: */
35: public class Monitorenter extends OneVariableInstruction {
36: /**
37: * Constructor.
38: *
39: * @param varName name of the variable representing the reference
40: * to the object being locked
41: */
42: public Monitorenter(String varName) {
43: super (varName);
44: }
45:
46: @Override
47: public MatchResult match(InstructionHandle handle,
48: ConstantPoolGen cpg, ValueNumberFrame before,
49: ValueNumberFrame after, BindingSet bindingSet)
50: throws DataflowAnalysisException {
51:
52: // Instruction must be MONITORENTER.
53: Instruction ins = handle.getInstruction();
54: if (!(ins instanceof MONITORENTER))
55: return null;
56:
57: // Ensure the object being locked matches any previous
58: // instructions which bound our variable name to a value.
59: Variable lock = new LocalVariable(before.getTopValue());
60: return addOrCheckDefinition(lock, bindingSet);
61: }
62: }
63:
64: // vim:ts=4
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