1 timna: a framework for automatically combining aspect mining analyses david shepherd 1 jeffrey...

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Timna: A Framework for Automatically

Combining Aspect Mining Analyses

David Shepherd1

Jeffrey Palm2

Lori Pollock1

Mark Chu-Carroll3

1University of Delaware

2Northeastern University

3IBM

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Introduction - What is AOP?

Aspect Oriented ProgrammingEach rectangle

represents a source file

Red lines represent source code lines implementing

concept A

figures from aspectj.com

Language Support for Crosscutting Concerns (CCCs)

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Introduction - A Closer Look at AOP

• Benefits of Refactoring into AOP• Increased "ilities"

– readability– maintainability– extensibility

• Crosscutting concerns (CCCs) are explicit

aspect DisplayUpdating {

after(): call(void Line.setP1(Point)) || call(void Line.setP2(Point)) { Display.update(); }}

class Line { private Point p1, p2;

Point getP1() { return p1; } Point getP2() { return p2; }

void setP1(Point p1) { this.p1 = p1;

} void setP2(Point p2) { this.p2 = p2;

}}

figures from aspectj.com

Display.update();

Display.update();

Responsibility of A

OP Community

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Working Assumptions

1.AOP can provide benefits in modularity for some problems

2.Crosscutting Concerns are dangerous; awareness is essential

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Targeted Problem: Mining

• Legacy Applications– refactor into AOP

figures generated by the AJDT

Aspect Mining is the process of finding these candidates

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Targeted Problem: Mining

3 different programmers implement 1 concept

Applications written with AOP, still problems...

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State of the Art

Researchers currently create a single analysis to perform aspect mining

Examples• Fan-in Analysis [Marin et al, WCRE 05]

• Code Clone Analysis [Shepherd et al, SERP 05]

• Dynamic Analysis [Breu et al, ASE 04]

• ...Little work done on combining analysis

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State of the Art• Fan-In public void credit(float amount) {

AccessController.checkPermission( new BankingPermission("accountOperation")); _balance = _balance + amount; } public void debit(float amount) throws InsufficientBalanceException { AccessController.checkPermission( new BankingPermission("accountOperation")); if (_balance < amount) { throw new InsufficientBalanceException("Insufficient total balance"); } else { _balance = _balance - amount; }

checkPermission

Good Candidate for Refactoring

public void checkOut(SpecialList items) { SpecialIterator it = items.iterator(); while(it.hasNext()) checkOut(it.next()); } public void markItems(SpecialList items) { SpecialIterator it = items.iterator(); while(it.hasNext()) ((Item)it.next()).mark();}

next

Bad Candidate for Refactoring

[Marin et al, WCRE 04]

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State of the Art

• Clone Detection

public void debit(float amount) throws InsufficientBalanceException {UserTransaction ut = ...;try {

ut.begin();... business logic ...ut.commit()

} catch (Exception ex) {ut.rollback();// rethrow after logging and wrapping

}}

Conventional Transaction Management

public void credit(float amount) {UserTransaction ut = ...;try {

ut.begin();... business logic ...ut.commit()

} catch (Exception ex) {ut.rollback();// rethrow after logging and wrapping

}}

[Shepherd et al, SERP 05]

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Remaining Challenges

• Combining Analyses– if (code clone & fan-in high), more

likely to be a refactoring candidate

• Running a large number of analyses– Methods with void return types– Getters and setters – ... Our framework (Timna) combines

analyses to make a decisionWe invented several new analyses,

use 11 total analyses

Humans do this during manual

mining

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Key Insight

Currently, humans are the best miners.

What is their process?

1. Manual Inspection2. Learn to identify candidates in

specific system3. Generalize to other systems4. Apply in other systems

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Automated Approach

1. Create Training Data1. Manual Tag Known Program2. Automatically Run Individual Mining

Analyses

2. Learn • Output: set of rules to classify

• boolean or categories

3. Classify Unknown programs• Output: refactoring candidates

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Create Training Data

Approach - Learning

KnownProgram

ManualTagging

Method A Class 2

Method B Class 1

Method C Class 1

Method D Class 3

Fan-in

No Parameters

Code Clone

Pairings

Method A Attributes Class 2

Method B Attributes Class 1

Method C Attributes Class 1

Method D Attributes Class 3

MachineLearning

ClassificationRules

Classification Table

Augmented Classification Table

Mining Analyses

1. Create Training Data2. Learn3. Apply

Method Identifier

Attributes

Classification

toolDone {?, ?, ?} refactor

setTool {?, ?, ? } don't refactor

exit {?, ?, ?} don't refactor

Start {?, ?, ?} refactor

Learn Rules

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Create Training Data

Learn Rules

Approach - Learning

ProgramManualTagging

Method A Class 2

Method B Class 1

Method C Class 1

Method D Class 3

Fan-in

No Parameters

Code Clone

Pairings





MachineLearning

ClassificationRules



Mining Analyses

1. Create Training Data2. Learn3. Apply

1. If( Fan-in > 5 and is-Void = true ), then (refactor)

2. If ( true ), then (don't refactor)

Method Identifier

Attributes

Classification

toolDone {6, false, 3}

refactor

setTool {1, true, 1 }

don't refactor

exit {0, false, 2}

don't refactor

Start {4, false, 2}

refactor

Final Result:Only output to Classifying

Phase

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UnknownProgram

Approach - Classifying

Method A

Method B

Method C

Method D

Fan-in

No Parameters

Code Clone

Pairings

Method A Attributes

Method B Attributes

Method C Attributes

Method D Attributes

Classifier






Mining Analyses


Completed Classification Table

Classify Unknown Program

Method Identifier

Attributes

Classification

showPrompt {6, false, 3}

refactor

takeOrder {1, true, 1 }

don't refactor

sendMessage {0, false, 2}

don't refactor

end {4, false, 2}

refactor

ClassificationRules

Method Identifier

Attributes

Classification

showPrompt {6, false, 3}

takeOrder {1, true, 1 }

sendMessage {0, false, 2}

end {4, false, 2}

Method Identifier

Attributes

Classification

showPrompt {}

takeOrder {}

sendMessage {}

end {}

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Evaluation Questions

1. Does combining analyses increase precision and recall?

2. Are generated rules effective on other programs?

3. Does categorical tagging increase performance?

4. What is the (time) overhead?5. Can rules help direct research

and evaluate new analyses?

Tagged in two different ways:Boolean: either refactor or

don't Categorical: either don't

refactor or a reason (category) why to refactor

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Experimental SetupSubject Programs• Training Program (JHotDraw, 11K LOC)• Testing Program (PetStore, 9K LOC)Steps1. Train 2. Test on Training Program3. Test on Testing ProgramMetrics• Precision and Recall• Time

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Experimental Results

Program not tagged, so can't calculate

recall

Timna: CatTimna: Bool


Precision = (number of good candidates returned) / (number of candidates returned)

Recall = (number of candidates returned) / (number of actual good candidates)

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1.Does combining analyses increase precision and recall?



Why is Fan-In performing poorly?

Single analyses work well for specific cases,

but fail to find all aspects.

In this case, combining analyses does increase precision and recall.

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2. Are generated rules effective on other programs?



In this case, the rules effectively mine from the testing program.

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3. Does categorical tagging increase performance?



In this case, the categorical tagging and the boolean tagging perform similarly.

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4. What is the (time) overhead?

Can be done incrementally, at each

compile/edit, or overnight

Only done onceCan be done

incrementally, at each compile/edit, or

overnight



From these results, we believe Timna could be integrated into an IDE without degrading

response time.

6.24s1.88s

----

5m28s5m28s2m04s2m04s

AnalyzeLearn

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5. Can rules help direct research and evaluate new analyses?

• [WARE 05] elaborates on use in evaluating new analyses• if analyses does not appear in

rules, it is providing no new information

• Human readable rules can help define style

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Contributions

• Technique to combine mining analyses to automatically identify refactoring candidates

• Demonstrated how to apply machine learning to learn good AOP style from canonical examples– generate human readable rules

• Invented several (7) novel mining analyses during our initial use of Timna

• Experimentally shown evidence that combining analyses can improve performance

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Possible Application

Of course! Whenever I change something in the drawing, I should

check to see if I damaged the drawing. Moving this concept to an aspect can eliminate a lot of similar

calls from my OOP code.

Provide hints, shaded by level of confidence

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Future Work

• Examine other aspect categorization– "Sorts" (Marin et al, ICSM 05)

• Extend with additional analyses– NLP-based analyses

• Apply to more unknown programs

1 timna: a framework for automatically combining aspect mining analyses david shepherd 1 jeffrey...

Documents

analysis slide

essential slide

void setp1point p1

void setp2point p2

usertransaction ut

aop figures

return p1

return p2