Re: getLocalVariable help

Hi Eric

The pc refers to the count within the bytecode array, so the instruction 
your interested in should have a pc associated with it (if the 
InstructionList has been changed these counts will be invalid) 
IntructionList.setPositions() sets these counts, or I think it must be 
done automatically by MethodGen.getMethod(). If you are changing the 
InstructionList you can request a LocalVariableGen which uses 
InstructionHandles which maintain their targets even if the 
InstructionList is edited later (InstructionHandles are then converted 
back to pc).

The pc parameter to getLocalVariable(..) is required because a local 
variable index can be re-used by another local variable with a different 
type once the original local variable is no longer required so the 
method needs to know which section of code or instruction you are 
interested in.

Importantly in my experience LocalVariable tables are not to be trusted 
to be correct, unless you have created them yourself and know they are 
correct. It is possible to remove the local variable table completely or 
have the local variable table completely wrong and still have valid and 
working bytecode. LocalVariableTables like LineNumberTables are not 
compulsory and are only there as debugging structures.

The only way I know of to get local variable information you can trust 
is from the instructions themselves.

I hope this helps

Bye Arrin

Eric Sheridan wrote:

>Group,
>
>I am a relatively new BCEL user and I am trying to invoke the getLocalVariable(int index, int pc) method on the LocalVariableTable object. I am unable to determine how to access the current pc, the second parameter required for the method. What is the best way to obtain this value?
>
>Thanks in advance for everyone's help!
>
>-Eric
>
>  
>

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