Toward Understanding How Developers Recognize Features in Source Code from Descriptions

Toward Understanding
How Developers Recognize
Features in Source Code
from Descriptions
Shinpei Hayashi†,Takashi Ishio‡,
Hiroshi Kazato*, andTsuyoshi Oshima**
†Tokyo Institute of Technology ‡Osaka University
*NTT DATA CORPORATION **NTT Software Innovation Center
1

Feature Location (FL)
 A first step of software maintenance
– Which modules/functions/methods implement a
feature?
– How they interact?
 Feature location process (for Java)
– A feature description  A list of relevant methods
– Search keywords to find seed methods
– Explore the seed methods and their neighbors
 Many automated FL techniques proposed
2

Feature Boundary
 Our aim:To clarify the boundary of features
– Or:To specify features by description, etc.
 Why?
– For analysts:Writing a clear change specification for
another implementer
– For researchers: Building a better FL benchmark
4
feature
(description)
set of modules

FL Benchmark
 A basic infrastructure for comparing/evaluating
FL techniques
 Content: Input of FL and corresponding output
– Source code
– A set of features
• Name of feature
• Natural language description explaining the feature
– Oracle: location of the feature
• e.g., Set of modules (methods in Java)
5

Usage of FL Benchmark
6
Benchmark
FL techniqueFL user/
researcher
Source
code
Feature name/
description
Dynamic trace
(for dynamic FL)
Input
Output
Set of modules
(ordered/unordered)
Set of modules
(Oracle)
Compare
Precision/Recall
effectiveness measure,
etc.

Current FL Benchmark
 Based on change history and issue tracking
– Assumes that modules modified when adding the
feature will implement the feature
– Associating features and modules by analyzing change
history- and issue-repositories
7
Change
historySVN
ITS
Release ofVer. 2.0
Extracting
source code
#123: Feature XXX
It would be nice if XXX...
r456: Implementing #123.
class Foo {
void foo() {
bar();
+ baz();
} ...
Location of Feature XXX: { Foo.foo(), ... }
Features:
• XXX
• ...

10
Gaps
(1) Feature description vs. Feature
– The description from ITS do not always describe
only the feature introduced by the revision.
(2) Feature vs. Change history
– Change history do not always record only the
changes related the the target feature.
Developer FeatureFeature
description
SVN
Change
history
read
(1)
(2)

Research Question
 Does a clearer description of a feature enable
developers to identify the same set of modules?
Developer Source
code
Feature
description
Developer Source
code
Clearer Feature
description
Output
Set of modules
Output
Set of modules
?
11

Original Description
 The description in the benchmark
–Extracted from ITS
12
As suggested in the [http://www.mucommander.
com/forums/viewtopic.php?f=2&t=938 forums]:
adding a “Skip all” button when an error occurs in
a multiple file move / copy operation would be a
nice feature to have.
muCommander Feature #231:
“Skip all” for errors that occur during a file transfer operation

Refined Description
 2 paragraphs for explaining base/core separately
muCommander has a feature that copies/moves
files selected by a user.When a user tries to
execute a copy, muCommander shows a dialog to
specify a destination directory. Pushing the Copy
button in the dialog starts a copy process. If an
error occurred during the copying of a file, then an
error dialog shows a message and asks the user to
skip the file, retry to copy the file, or cancel the
copy process.
The new feature is “Skip All.”The dialog to specify a
destination directory has a new check box with the
caption is “Skip errors.” If a user checked the box,
then muCommander automatically skips a file if an
error occurred, without showing a dialog.The error
message dialog also has a new button “Skip all.” If
the button is pushed, then muCommander shows
no error dialog in further errors, as “Skip errors” is
checked.
Base behavior:
Explanation of basic
behavior which exists
before implementing the
target feature
Core behavior:
Explanation of the target
feature based on the
recorded change
13

Controlled Experiment
 Task: Read a description and vote for modules
 2 rounds
– One for Feature 1 w/ {original, refined} description
– One for Feature 2 w/ {original, refined} description
 Accumulates the votes of all subjects
Subject
Feature
description
Input
Source
code
Output
Votes
This module is
- relevant.
- useful (for understanding).
- irrelevant.
14

Subjects and Dataset
 Subjects
– 18 subjects (Students in Osaka U. + in Tokyo Tech.)
 Dataset: using Dit et al.’s Benchmark
– Feature 1: jEdit #1747300
– Feature 2: muCommander #231
 Obtained treatments
– 9 of Feature 1 w/ original description
– 9 of Feature 1 w/ refined description
– 9 of Feature 2 w/ original description
– 9 of Feature 2 w/ refined description
15

Result
16
GutterOptionPane.addFoldStyleChooser()
Gutter.Gutter(TextArea)
Gutter.paintLine(Graphics2D,...)
TriangleFoldPainter.paintFoldEnd(Gutter,...)
TriangleFoldPainter.paintFoldStart(Gutter,...)
GutterOptionPane._init()
GutterOptionPane._save()
TriangleFoldPainter.paintFoldMiddle(Gutter,...)
EditPane.propertiesChanged()
Gutter.setFoldPainter(FoldPainter)
StandaloneTextArea.StandaloneTextArea(IPropertyManager)
ShapedFoldPainter.paintFoldStart(Gutter,...)
ShapedFoldPainter.paintFoldEnd(Gutter,...)
FoldPainter.paintFoldStart(Gutter,...)
FoldPainter.paintFoldEnd(Gutter,...)
FoldPainter.paintFoldMiddle(Gutter,...)
JEditTextArea.getFoldPainterName()
JEditTextArea.getFoldPainter()
TextArea.getFoldPainter()
ServiceManager.getServiceNames(String)
AbstractOptionPane.save()
DummyFoldHandler.DummyFoldHandler()
ExplicitFoldHandler.ExplicitFoldHandler()
IndentFoldHandler.IndentFoldHandler()
JEditBuffer.propertiesChanged()
MouseHandler.mousePressed(MouseEvent)
JEditTextArea.JEditTextArea(View)
DefaultFoldHandlerProvider.DefaultFoldHandlerProvider()
ExplicitFoldHandler.getFoldLevel(JEditBuffer,...)
ServiceManager.getService(String,...)
Gutter.updateBorder()
CircleFoldPainter.CircleFoldPainter()
Gutter.setBorder(Border)
SquareFoldPainter.SquareFoldPainter()
StandaloneTextArea.initPainter()
TextAreaPainter.setFoldLineStyle(SyntaxStyle[])
TriangleFoldPainter.TriangleFoldPainter()
CircleFoldPainter.paintFoldShape(Graphics2D,...)
SquareFoldPainter.paintFoldShape(Graphics2D,...)
ShapedFoldPainter.paintFoldMiddle(Gutter,...)
Gutter.paintComponent(Graphics)
MouseHandler.getFoldEndOffset(int)
DefaultFoldHandlerProvider.addFoldHandler(FoldHandler)
StandaloneTextArea.initGutter()
ShapedFoldPainter.paintFoldShape(Graphics2D,...)
JEditBuffer.JEditBuffer()
DisplayManager.expandFolds(int)
Gutter.setGutterEnabled(boolean)
Included in
the goldset
Not included in
the goldset
630369
PreferencesDialog.setCommitButtonsEnabled(boolean)
GeneralPreferencesDialog.setCommitButtonsEnabled(boolean)
PreferencesDialog.initUI()
GeneralPreferencesDialog.componentChanged(PrefComponent)
PreferencesDialog.commit()
ThemeEditorDialog.componentChanged(PrefComponent)
PrefTextField.addDialogListener(PreferencesDialog)
PrefComboBox.addDialogListener(PreferencesDialog)
GeneralPreferencesDialog.GeneralPreferencesDialog()
PrefCheckBox.addDialogListener(PreferencesDialog)
PrefRadioButton.addDialogListener(PreferencesDialog)
ColorButton.setCurrentColor(Color,...)
FoldersPanel.FoldersPanel(PreferencesDialog)
GeneralPanel.GeneralPanel(PreferencesDialog)
MailPanel.MailPanel(PreferencesDialog)
MiscPanel.MiscPanel(PreferencesDialog)
ThemeFontChooserListener.stateChanged(ChangeEvent)
GeneralPreferencesDialog.commit()
PreferencesDialog.actionPerformed(ActionEvent)
PreferencesDialog.PreferencesDialog(Frame,...)
PrefEncodingSelectBox.addDialogListener(PreferencesDialog)
PreferencesDialog.PreferencesDialog(Dialog,...)
ThemeEditorDialog.commit()
PreferencesDialog.componentChanged(PrefComponent)
ThemeEditorDialog.ThemeEditorDialog(Dialog,...)
ShowPreferencesAction.performAction()
PreferencesDialog.checkCommit()
PrefTable.addDialogListener(PreferencesDialog)
AbstractButton.setEnabled(boolean)
ThemeEditorDialog.checkCommit()
ThemeData.isIdentical(ThemeData)
AppearancePanel.AppearancePanel(PreferencesDialog)
CustomizeDialog.initUI()
TransferDestinationDialog.TransferDestinationDialog(MainFrame,...)
ShortcutsPanel.ShortcutsPanel(PreferencesDialog)
CommandBarDialog.createCustomizationPanel()
CustomizeDialog.actionPerformed(ActionEvent)
LicenseDialog.createLicensePanel()
PrefComponent.hasChanged()
QuitDialog.QuitDialog(MainFrame)
InitialSetupDialog.InitialSetupDialog(Frame)
AboutDialog.createCreditsPanel()
Included in
the goldset
Not included in
the goldset useful (original)
relevant (original)
relevant (refined)
useful (refined)
jEdit muCommander

Result
17
GutterOptionPane.addFoldStyleChooser()
Included in
the goldset
Not included in
the goldset
630369
PreferencesDialog.setCommitButtonsEnabled(
GeneralPreferencesDialog.setCommitButtonsEPre
GeneralPreferencesDialog.comp
ThemeEdito
Modules included
in the goldset
Modules do not included
in the goldset
# votes when using
original description
# votes when using
refined description

More vs. Less votes
 Differences of # votes to modules in goldset
– Voted by many subjects: actually relevant?
– Voted by less subjects: actually irrelevant?
 Unsuitableness in the benchmark?
18
e.addFoldStyleChooser()
Included in
the goldset
Not included in
the goldset
Included in
the goldset
Not included in
relevant (original)
relevant (refined)
useful (refined)
16 votes 1 vote
Finding 1:

Original vs. Refined
 More subjects voted some modules in goldset
using refined description
 Refined description contributed for
some modules?
19
Included in
the goldset
Not included in
the goldset
Included in
the goldset
Not included in
relevant (original)
relevant (refined)
useful (refined)
Finding 2:

Votes and Goldset
 Many votes to some modules out of the goldset
– Including the ones mostly using refined description
 Actually relevant?
20
Included in
the goldset
Not included in
the goldset
Included in
the goldset
Not included in
relevant (original)
relevant (refined)
useful (refined)
Finding 3:

Further Directions
 More investigations about descriptions
 Fuzzy benchmark
– Likelihood values are added based on votes
 Support for writing clearer descriptions
22
• PreferenecsDialog.initUI():0.7 (7 of 10 developers answered relevant)
...
List of
modules
fragile against
changes
Abstract
description
insufficient to
recognize
?

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