Refactoring Project

• Arne de Bruijn arbruijn@students.cs.uu.nl
• Martin Bravenboer mbravenb@students.cs.uu.nl

Topics

Progress - Testing - Programs - Documents - Links - Ideas

Progress

Done:

• Examination of the refactoring tool by Chris Seguin
• Overview of the AST & the Java Grammer file for JavaCC and JJTree
• Tree view of the AST of a method from the UI
• Source view of a method
• Select statements view of a method (not finished yet)

To do:

• Check the role and scope of variables
• Create the parameter list of the method
• Check if the method should return a value and the type of this value.
• Create a new method
• Remove the statements from the parent method

Testing

Maybe we could accept the example refactoring in the refactoring book of Martin Fowler as a test case. We could devide it into several test cases.

Programs

• Source of the tool + extentions we've done so far: http://www.students.cs.uu.nl/people/arbruijn/sg/refactoring/jrefsg02.zip

• First Java Parsing excercise with extra java code in the parser and ast: http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/ParseSimpleJava.zip Start with: parse.simpejava.JavaParser <JAVA_SOURCE_FILE>. The test only supports package, imports and class declarations. Extract the zip file into a directory called parse.

• Java 2 Parser genenerated by the grammar file and building the mentioned AST: http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/JavaParser.zip

Documents

• To do list for extract method: http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/extractMethod.doc

• Complete overview of the Abstract Syntax Tree of the Java 2 Language(Grammar file by David Williams) in quite a large Powerpoint document (Zoom to 100% to view the tree): http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/Java2ParseTree.ppt

• Java 2 Grammar File for Jjtree: http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/Java1.2.jjt

• Some comments and analysis of the Refactoring Tool by Chris Seguin (in dutch): http://www.students.cs.uu.nl/people/mbravenb/sg/refactoring/RefactoringTool.doc

• Provisional version of report (in dutch): http://www.students.cs.uu.nl/people/arbruijn/sg/refactoring/verslag.doc

Links

• Javacc: the Parser Generator for Java. Jjtree: the Abstract Syntax Tree builder preprocessor for Javacc. http://www.metamata.com/javacc/

• The Refactoring book of Martin Fowler: http://www.refactoring.com

• Refactoring Object-Oriented Frameworks, Thesis by William D. Opdyke. More academical view on refactoring and one of the first papers on refactoring: ftp://st.cs.uiuc.edu/pub/papers/refactoring/opdyke-thesis.ps.Z Many information on safety and preserving behaviour.

Ideas

• Make method extraction possible. Maybe we should extend the grammar for this.
• You should be able to view the code of a method from the uml view. The pretty printer should be used for this. This feature can be used for code selection in the extract method refactoring.
• Variable information (currently not supported): references should know what the type of the variable is and where it is defined etc.
• Editing information: is a variable in a piece of code used for reading or also for writing purposes?

Other ideas which could be used to write a new tool:

• Create a tool which supports safe refactoring by warning for any possible error which could occure. It should always create correct Java code or it should warn if this isn't possible.
• Refactorings should be as small and reusable as possible to make it easy to add refactorings.
• Make a very good parse tree which can be used for many refactorings and other program elements:
  • Checking methods should be included in the parse tree to make them reusable for other refactorings.
  • Methods should know where they are called to make refactorings efficient and easy.
  • Classes should know where they are referenced so they can warn that items when classnames or other classitems change.
• Try to use code of the Refactoring Tool by Chris Seguin when some problems are solved there in a nice way.