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From "Showalter, Jim" <Jim_Showal...@intuit.com>
Subject RE: [BCEL] Re: How can I recover .class references separate from other references to classes using BCEL?
Date Sun, 10 Sep 2017 21:11:24 GMT
This works:

	public void visitCode(final Code obj) {
		ConstantPoolGen cpg = new ConstantPoolGen(javaClass.getConstantPool());
		InstructionList list = new InstructionList(obj.getCode());
		Iterator<InstructionHandle> iter = list.iterator();
		while (iter.hasNext()) {
			Instruction instruction = ((InstructionHandle)iter.next()).getInstruction();
			if (instruction instanceof LDC) {
				LDC load = (LDC)instruction;
				if (javaClass().getConstantPool().getConstant(load.getIndex()).getTag() == Const.CONSTANT_Class)
{
					Object val = load.getValue(cpg);
					System.out.println(type.classFileName() + ": " + val);
				}
			}
		}
	}

-----Original Message-----
From: Stephan Herrmann [mailto:stephan.herrmann@berlin.de] 
Sent: Sunday, September 10, 2017 1:12 PM
To: user@commons.apache.org
Subject: [BCEL] Re: How can I recover .class references separate from other references to
classes using BCEL?

quick guess: check if the previous instruction is ldc.

HTH,
Stephan

On 10.09.2017 21:50, Showalter, Jim wrote:
> The use case is, suppose you want to recover the source from a .class file.
> 
> In the original source, it said:
> 
> public class SomeExperiment {
>       public static void main(String[] args) {
>       System.out.println(SomeOtherClass.class); <<< WANT TO RECOVER THE ".class"
FROM HERE
>       }
> }
> 
> In the visitor I wrote, there's an override:
> 
>       public void visitConstantClass(final ConstantClass obj) {
>             String className = JavaUtils.dotsToSlashes(javaClass().getConstantPool().getConstant(obj.getNameIndex()).toString());
>            System.out.println(class file name + ": " + className);
>       }
> 
> Dumping out the data on a .class from a .java file that contains no occurrences of the
string ".class", I get:
> 
> com/intuit/qbo/Misc.class: com/intuit/qbo/Misc$Reader
> com/intuit/qbo/Misc.class: com/intuit/qbo/util/SomeException
> com/intuit/qbo/Misc.class: com/intuit/qbo/Misc
> com/intuit/qbo/Misc.class: com/intuit/qbo/api/MiscIf
> 
> This means ClassConstant isn't just for .class references. It's for all references to
classes.
> 
> How can I use BCEL to recover the original ".class" reference in SomeExperiment?
> 
> Jim Showalter
> Programmer
> Intuit, 2003H-265Z
> Garcia Avenue
> Mountain View, CA 94043
> (408) 353-4954
> (408) 204-1661
> 
> 


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