Call%20Data%20Collection%20-%201

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Aspect Browser Plus Ling Neil Patricia
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Motivation

• When modifying code it is important to find all
  dependencies
• Backtracing is helpful when learning new code

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Scenario

• Find all references to a member function called
  getName that is in a class called Class
• Looking for
• classNew.getName()
• myClass.getName()
• anything.getName()
• As long as it is of type Class

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How to do this with AB

• Create getName() aspect
• May result in a lot of false positives
• Create Class aspect and note all variables that
  have this type. Search for variable.getName()
• Tedious
• Detracts from task at hand
• Wont find implicit this references
• Take advantage of naming conventions
• No guarantee

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Goals

• Keep Aspect Browser language independent
• Minimize modification to AB
• Modularize language dependent portion

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How did we do it?

• Language dependent component creates a database
• Can use any method desired to populate file
• Aspect Browser uses database when Aspect Plus
  Aspects are created
• getName_at__at_Class

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Demo

• Want to modify getName() function of a class
  called Class

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What went right?

• Modularization was almost perfect
• I still have no idea how Patricias code works
• Patricia and Ling have never seen my
  modifications
• Integration with Aspect Browser was almost
  trivial.
• AspectPlus inherited from Aspect
• Factory created AspectPlus based on string parse

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What went wrong?

• We couldnt use this on Aspect Browser itself
  because of AspectJ. Bummer!
• Emacs interface is not perfect

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Whats next?

• Support for another language (c)
• Support member variable references as well
• Support RegExp matches
• Fix bug with emacs highlighting

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Questions?
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Extra Slides Time Permitting
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Call Data Collection Implementation

• Java bytecode based collector. Requires
  pre-compiled files.
• Uses Apache BCEL to read and parse class files.
• Extracts source file, line number, target type,
  and function name for each call.

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Call Collection Issues

• Requires optional line number and local variable
  tables. Debug compile generates them.
• Compilation and collection should be automated.
• Virtual calls - currently indicates only match to
  compile time type.

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Function of AspectPlusDatabase

• User Interface calls findAspect with sFile, sType
  and sFunction.
• findAspect goes through the Database and returns
  the line for every occurrence of them.

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Implementation1

• AspectPlusDatabase goes through the Database once
  and saves all the information in a hashmap for
  later uses.

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Implementation2

• AspectPlusDatabase finds the vector by key sFile,
  then finds sType and sName in the vector.