任何高级字节码编辑器？

Question

Suppose I have a the following in Scala

object Foo {
  var functions: List[String => String] = Nil // can be any type to any type.
  def addFunc(f:String => String) = functions = f :: functions
}

At runtime, I am given Foo with some functions added. I now want to construct a new .class file implementing something like following in Scala:

object MyObject { 
  def process1(s:String) = // call Foo.functions(1)
}

I then want to save MyObject in bytecode that can be executed later on even when Foo is not there.

The above is just an example to show what I want to do . I am given the names MyObject , process1 , and I have to generate an executable file MyObject.class . The source of MyObject is not needed (it could well have been Java source).

So, at a high level, we need to take memory "snapshot" of Foo.function(1) , convert that snapshot into bytecode to store, and generate bytecode of MyObject using this.

All the bytecode engineering libraries I found are too low-level, so I was wondering if there is a higher level library that lets me deal with abstract objects such as functions etc.

Answer 1

Have you looked at the Tree model of ASM ? I've only used the Event model before, but the Tree sounds like just what you're looking for. You'll find an overview in section 1.2.2 of the ASM user guide (a PDF--I don't think there's an HTML version, or I'd link that).

Answer 2

I will also recommend ASM framework. There is a paper from AOSD'07 about implementing common bytecode transformation patterns with ASM. Sections "Merging Two Classes into One" and "Inline Method" describing bytecode transformations very close to yours.