2009/1/6 <zagiatakrapo...@gmx.ch>: > Hi guys, > > The recently opened the bug no. 46254, there I described the problems with > dup instructions as insertion points. <snip>
I can see the argument for using the very same instance for common instructions (for example, lower memory footprint). I think that using Instruction instances as markers within an InstructionList is possibly misusing the method; BCEL provides InstructionHandle for this very purpose. Let me explain my reasoning... The problem is that this suggestion is making an Instruction both an abstraction of a byte-code instruction and also a unique instance of that byte-code within a particular InstructionList. Compare what Java does with Strings If you write "Hello" in one place and "Hello" in another, they are the very same object. But if you read the string "Hello" from a file, it will almost certainly be a different object, even though it is equal (to the point of being 100% substitutable). To complete the analogy, two DUP instances are substitutable (IIRC). Java deals with the ambiguity of identity in places like List.indexOf() by stating that it finds the index of the "first occurrence". I would be against removing all the common instruction instances (for example, in InstructionConstants). I would rather suggest that the insert method's JavaDoc is improved to clarify what it does. (All IMHO, of course.) Kind regards, Matthew --------------------------------------------------------------------- To unsubscribe, e-mail: bcel-dev-unsubscr...@jakarta.apache.org For additional commands, e-mail: bcel-dev-h...@jakarta.apache.org
