How to use UserValue to implement FindBugs plugin

UserValue is a good way to mark local variable. By this marking, you can chase item or classify type of item.

To use operand stack, your detector should extend OprandStackDetector or its subclass.

• OprandStackDetector
  • OpcodeStackDetector#getStack()
• OpcodeStack
• OpcodeStackValue
  • OpcodeStack.Item#setUserValue()
  • OpcodeStack.Item#getUserValue()

And, this is key point, your detector should be annotated with @CustomUserValue to use UserValue. This marker annotation will help FindBugs to understand your detector and treat OprandStack correctly.

• @CustomUserValue

If you forget this annotation, you will find that your UserValue is lost in some case, especially around branching code (like if).

• issue of my FindBugs plugin