1. Building an Eclipse plugin to
recommend changes to developers
Master thesis defense – June 2013
Snaps François – Université catholique de Louvain – EPL
Advisor & Guidance – Prof. Kim Mens & Dr. Angela Lozano
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Master thesis defense

2. Context
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Maintenance and extension of existing systems
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Frequent and complex operations
Difficulty: developers need to interact with unfamiliar code
Before becoming productive, a developer needs to know:
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The limits and bounds of the existing system
Where and how to integrate his modifications in the system
The conventions, coding idioms, etc…
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Master thesis defense

3. Solution
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Build a tool to facilitate this interaction between the
developer and the existing system
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Mendel’s approach:
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Extract regularities from an existing system
Recommend implementation hints
as changes to the developer
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Master thesis defense

4. Mendel: a Genetic Metaphor
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“Tell me who your family is, I will tell you what you should
look like”
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Select an entity
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Find its family members according to a family definition
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Extract dominant and recessive traits of the family
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Family definition (in this example):
all apples belonging to the previous picture
Dominant trait: “color: green” is shared by all other family members
Recommend family trait not implemented by the selected entity
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Recommendation: the selected apple should also have the color green
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Master thesis defense

5. Family Definition: a Key Factor
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What if, instead of the previous definition, we now use
this definition:
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All apples belonging to the same tree as the selected apple
Ø No more “color: green” trait recommended
Ø Possible other family traits (taste, form,…)
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Objective: supporting multiple family definitions
Study the impact of the family definition on:
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The quality of the recommendations produced
The type of the recommendations produced
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Master thesis defense

6. Predefined families
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Default family (Mendel definition)
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For classes & interfaces : all siblings and nephews of the
selected class or interface
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+ distinction between abstract and concrete classes.
For methods : all methods with the same name as the selected
method within the siblings and nephews of the selected
method’s class.
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Master thesis defense

7. Predefined families
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Identifiers Family
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Implements Family
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Relation: part of the entity’s
name
Parameterized family
Relation: implements and
extends links
Specialized family: classes and
interfaces
Callers Family
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Relation: method called
Parameterized family
Specialized family: methods
and constructors
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Master thesis defence

8. Validation
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Hypothesis : a “relevant” recommendation is one that has
actually been implemented by developers
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Technique : analyzing multiple versions of a same project
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Produce recommendations for each version
Verify if these recommendations are implemented in a later
version
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Master thesis defense

9. Validation: implementation
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Multiple parsing issue
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Particularity of Mendel’s approach
Solution used: database
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Extractor tool
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Parses the entire source code of the version and stores it into the
database
Validation on the database
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Master thesis defense

10. Results
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Some family definitions are more suited for some
recommendations types than others
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“Method implemented” type
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Implements family
23 of 1505 recommendations are actually implemented
¨ 41 of 50 recommendations are rated as relevant
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Identifiers family (M2)
0 of 828 recommendations are actually implemented
¨ 22 of 50 recommendations are rated as relevant
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Master thesis defense

11. Future Work
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Improve the validation filters
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Better family thresholds
Better family definitions
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Restrict the number of entities analyzed
Restrict the number of irrelevant recommendations produced
Example: “extends” type and our Default family
Validation with real users
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Master thesis defense

12. Conclusion
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Supporting multiple family definitions
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Allows to select the most appropriate family for a type of
recommendation
Avoids the case where a family definition struggles to produce
some recommendation types
Allows to compare recommendations from a different point of
view (different family definitions)
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Master thesis defense