Migration and Refactoring - Identifying Overly Strong Conditions in Refactoring Implementations

Identifying overly strong conditions in refactoring implementations

Gustavo SoaresMelina Mongiovi

Rohit Gheyi

[email protected] University of Campina Grande

terça-feira, 11 de outubro de 2011

mailto:[email protected]


2

Employee

...

Engineer

...name

Salesman

...name

Duplicated code


Pull Up Field Refactoring

3

Employee

...

Engineer

...name

Salesman

...name

Employee

...name

Engineer

...

Salesman

...

Refactoring engines

Precondition The name field is not declared in class Employee


preconditions

It’s difficult to specify and implement preconditions

4


preconditionsImplemented

Overly weakcondi0ons allow

unsafe transforma+ons

Overly strong condi0onsprevent safe transforma+ons

Problem

5


Motivating example

A

B

private int fint getF() : f

Pull up field

JRRT

GetF() cannot access variable f

6


A

B


Pull up field

JRRT

GetF() cannot access variable f

A

B


Pull up field

A

protected int f

B

int getF() : f

7

Overly strong


Identifying overly strong conditions

An evaluation on 3 refactoring engines

JRRT

8


input

expected output

Testing

9


input

expected output

Testing

10

engine

output

Overly strong


input

Overly Strong

conditions

11

Differential testing

Overly StrongCondition

Exhaustively generating programs


2 Class, 2 Method, 2 Field

One subclass declaring a field

12


public class Class0 {public int method2(){ return 10; }}class Class1 extends Class0 { public int method1(){ return 20; } public int method2(){ super.k(); }}



Java Meta model Alloy Solutions Java programs

2 Class, 2 Method, 2 Field

One subclass declaring a field

13


input

expected output

14

Differential testing

Overly StrongCondition

Exhaustively generating programs


B.getF

No behavioral change was found

0/4 0/4

A

B


A

protected int f

B

int getF() : f4

15


Technique

Differentialtesting

Classifying

overly strongpreconditions

SPEC

16


Classifying overly strong conditions

A.test cannot access method A.k

B.m cannot access method B.n

C.test cannot access method C.k

cannot access method

OTC

17


Evaluation

18


Up to 10 refactoringsRefactoring Eclipse JRRT NetBeansRename Class X X X

Rename Method X X XRename Field X X X

Push Down Method X X XPush Down Field X X XPull Up Method X X XPull Up Field X X X

Encapsulate Field X XMove Method X XAdd Parameter X X

2 Packages, 3 classes, 4 methods, 2 fields19


ResultsRefactoring Program

Rejected Beh. Pres.Rejected Beh. Pres.Rejected Beh. Pres. Overly Strong ConditionOverly Strong ConditionOverly Strong ConditionRefactoring Program

Ecl JRRT NetB Ecl JRRT NetBRename Class 4660 446 0 0 2 0 0

Rename Method 4752 4802 419 0 4 1 0Rename Field 3168 200 0 0 2 0 0

Push Down Method 9366 59 40 0 1 1 0Push Down Field 4800 0 0 0 0 0 0Pull Up Method 10322 251 398 0 2 2 0Pull Up Field 4320 744 584 0 1 1 0

Encapsulate Field 900 176 1536 - 1 1 -Move Method 3002 367 135 - 2 1 -Add Parameter 4279 79 0 - 2 0 -

Total 42774 7124 3112 0 17 7 0

20


JRRT feedbackRefactoring Strong conditions

Rename Method overriding has changed

Push Down Method cannot access method

Pull Up Methodmethod is used

Pull Up Methodcannot access method

Pull Up Field cannot access variable

Encapsulate Field cannot insert method here

Move Method cannot inline ambiguous method call

21


JRRT feedbackRefactoring Strong conditions Cause

Rename Method overriding has changed precondi+on

Push Down Method cannot access method incorrect analysis

Pull Up Methodmethod is used incorrect analysis

Pull Up Methodcannot access method incorrect analysis

Pull Up Field cannot access variable feature not implemented

Encapsulate Field cannot insert method here feature not implemented

Move Method cannot inline ambiguous method call incorrect analysis

22


Conclusions

preconditionsImplemented

DifferentialTesting

+

overly strong conditions + overly weak conditions

23


Identifying overly strong conditions in refactoring implementations

Gustavo SoaresMelina Mongiovi

Rohit Gheyi

[email protected] University of Campina Grande

24




Migration and Refactoring - Identifying Overly Strong Conditions in Refactoring Implementations

Technology

Transcript of Migration and Refactoring - Identifying Overly Strong Conditions in Refactoring Implementations