Investigating the Change-proneness of Service Patterns and Antipatterns

Investigating the Change-proneness of
Service Patterns and Antipatterns
Francis Palma, Le An, Foutse Khomh, Naouel Moha, and Yann-Gaël Guéhéneuc
École Polytechnique de Montréal, Canada
SOCA 2014, Matsue, Japan

Problem Context (1/3)
Service-based Systems
2 of 21Investigating the Change-proneness of Service Patterns and Antipatterns
SOAP
Web Services
SCA Systems

SOAP
Web Services
SCA Systems
Design Patterns

SOAP
Web Services
SCA Systems
Maintenance
Evolution
SOAP Web Services
SCA Systems
Design Patterns

SOAP
Web Services
SCA Systems
Maintenance
Evolution
SOAP Web Services
SCA Systems
- may degrade the design
- may degrade the QoS = Antipatterns
Design Patterns

2 of 21
1. Highly change-prone?
2. Require more maintenance
efforts or cause expensive
maintenance?
SOAP Web Services
SCA Systems
Existing
Antipatterns
?
Investigating the Change-proneness of Service Patterns and Antipatterns

Problem Context (2/3):
Service Antipatterns and Patterns
Multi Service Antipattern

Problem Context (2/3):
Service Antipatterns and Patterns
Multi Service Antipattern
Proxy Service Pattern
Proxy
Service
Actual
Service
Calls Calls
Client

Problem Context (3/3): Detection vs. Impact
• Detection of service patterns? (SODOP, Demange et al. 2013)
• Detection of service antipatterns? (SODA, Moha et al. 2012)
• Improve/degrade the design and the QoS?
• Facilitate/hinder the maintenance and evolution of an SBS?
- impact on the change-proneness, i.e., maintenance cost?

Problem Context (3/3): Detection vs. Impact
Change-proneness of a service*
- number of changes
 the frequency of changes on a service source files
- code churns
 the size of changes on a service source files
4 of 21
• Detection of service patterns? (SODOP, Demange et al. 2013)
• Detection of service antipatterns? (SODA, Moha et al. 2012)
• Improve/degrade the design and the QoS?
• Facilitate/hinder the maintenance and evolution of an SBS?
- impact on the change-proneness, i.e., maintenance cost?
*Code Churn: A Measure for Estimating the Impact of Code Change: Sebastian G. Elbaum and John C.
Munson (1998)

Research Questions
• RQ1: What is the relation between service patterns and
change-proneness?
• RQ2: What is the relation between service antipatterns and
change-proneness?
• RQ3: What is the relation between particular kinds of service
antipatterns and change-proneness?
• Confounding impact of OO code-level smells

Outline
- Analysed System: FraSCAti OW2
- Study Design
- Case Study Results
- Conclusion and Future Work

FraSCAti OW2
frascati.ow2.org
Investigating the Change-proneness of Service Patterns and Antipatterns
Total Services 130 (62 analysed)
Total Size 170 KLOC
Total Changed Files 15,863*
Total Java Source Files 9,020*
Total Changes 71,151*
Total Code Churns 62,676,363*
6 of 21
*Entire commit history

Study Design

Study Design: FraSCAti Commit
[[frascati-commits]] [1196] trunk/tinfi: More refactoring.
 Subject: [[frascati-commits]] [1196] trunk/tinfi: More refactoring.
 From: Lionel.Seinturier@xxxxxxx
 Date: Sat, 13 Dec 2008 21:41:32 +0100 (CET)
 Delivered-to: frascati-commits@xxxxxxx
Title: [1196] trunk/tinfi: More refactoring.
Revision
1196
Author
seintur
Date
2008-12-13 21:41:32 +0100 (Sat, 13 Dec 2008)
Log Message
More refactoring.
Modified Paths
 trunk/tinfi/runtime/oo-dyn/src/main/java/org/ow2/frascati/tinfi/Tinfi.java
 trunk/tinfi/runtime/oo-dyn/src/main/java/org/ow2/frascati/tinfi/TinfiBootstrapComponentImpl.java
Added Paths
 trunk/tinfi/opt/comp/src/main/java/org/ow2/
 trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/
 trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/
 trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/
 trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/FCCompCtrlSourceCodeGenerator.java
 trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/InitializerCompCtrlSourceCodeGenerator.java
Removed Paths
 trunk/tinfi/opt/comp/src/main/java/org/scorware/
 trunk/tinfi/runtime/oo-dyn/src/main/java/org/scorware/
Property Changed
 trunk/tinfi/tinfi-mixed/
Diff
Copied:
trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/FCCompCtrlSourceCodeGenerator.j
ava (from rev 1186,
trunk/tinfi/opt/comp/src/main/java/org/scorware/tinfi/juliac/FCCompCtrlSourceCodeGenerator.jav
a) (0 => 1196)
---
trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/FCCompCtrlSourceCode
Generator.java (rev 0)
+++
trunk/tinfi/opt/comp/src/main/java/org/ow2/frascati/tinfi/juliac/FCCompCtrlSourceCode
Generator.java 2008-12-13 20:41:32 UTC (rev 1196)
@@ -0,0 +1,167 @@
+package org.ow2.frascati.tinfi.juliac;
+
+import java.io.IOException;
+
+import org.objectweb.fractal.api.control.AttributeController;
+import org.objectweb.fractal.api.type.InterfaceType;
+import org.objectweb.fractal.julia.control.attribute.CloneableAttributeController;
+import org.objectweb.fractal.julia.type.BasicInterfaceType;
+import org.objectweb.fractal.juliac.InitializerClassGenerator;
+import org.objectweb.fractal.juliac.Juliac;
+import org.objectweb.fractal.juliac.JuliacConfig;
+import org.objectweb.fractal.juliac.proxy.AttributeControllerClassGenerator;
+import org.objectweb.fractal.juliac.proxy.InterfaceImplementationClassGenerator;
+import org.objectweb.fractal.juliac.proxy.ProxyClassGenerator;
+import org.objectweb.fractal.juliac.ucf.UnifiedClass;
+import org.osoa.sca.annotations.Callback;
+
+/**
+public class FCCompCtrlSourceCodeGenerator
+extends org.objectweb.fractal.juliac.opt.comp.FCCompCtrlSourceCodeGenerator {
+
+ public FCCompCtrlSourceCodeGenerator() {
+ super();
+ }
+
+
+ // -----------------------------------------------------------------------
+ // Implementation of the OptLevelSourceCodeGenerator interface
+ // -----------------------------------------------------------------------
+
....
....
....
Modified: trunk/tinfi/runtime/oo-dyn/src/main/java/org/ow2/frascati/tinfi/Tinfi.java (1195 => 1196)
--- trunk/tinfi/runtime/oo-dyn/src/main/java/org/ow2/frascati/tinfi/Tinfi.java
2008-12-12 18:10:44 UTC (rev 1195)
+++ trunk/tinfi/runtime/oo-dyn/src/main/java/org/ow2/frascati/tinfi/Tinfi.java
2008-12-13 20:41:32 UTC (rev 1196)
@@ -21,7 +21,7 @@
* Author: Lionel Seinturier
*/
+package org.ow2.frascati.tinfi;
import org.objectweb.fractal.api.Component;
import org.objectweb.fractal.api.Type;
Modified: trunk/tinfi/runtime/oo-
dyn/src/main/java/org/ow2/frascati/tinfi/TinfiBootstrapComponentImpl.java (1195 => 1196)
--- trunk/tinfi/runtime/oo-
dyn/src/main/java/org/ow2/frascati/tinfi/TinfiBootstrapComponentImpl.java 2008-12-
12 18:10:44 UTC (rev 1195)
+++ trunk/tinfi/runtime/oo-
dyn/src/main/java/org/ow2/frascati/tinfi/TinfiBootstrapComponentImpl.java 2008-12-
13 20:41:32 UTC (rev 1196)
@@ -21,7 +21,7 @@
* Author: Lionel Seinturier

Study Design
 Detection of Service Patterns:
SODOP – Service Oriented Detection Of Patterns (Demange et al. 2013)
 Detection of Service Antipatterns:
SODA – Service Oriented Detection for Antipatterns (Moha et al. 2012)
8 of 21
Names Detected
Instances
Involved Java
Source Files
Patterns
Adapter 1 14
Basic Service 5 54
Facade 3 62
Proxy 3 61
Antipatterns
Bloated Service 3 25
Bottleneck Service 2 24
God Component 2 4
Multi Service 1 5
Nobody Home 4 12
Service Chain 3 10
The Knot 1 24
Tiny Service 1 24
OO Code Smells - 26,381 3,717

Study Design

Study Design: Variables
 Independent Variables
Eight service antipatterns and four service patterns
i. f1
i  a file i was involved in the implementation of at least one pattern (RQ1)
ii. f2
i  a file i was involved in the implementation of at least one antipattern (RQ2)
iii. f3
i,j  a file i was involved in the implementation of antipattern j (RQ3)
 Dependent Variables
Change-proneness of services' source files
i. total number of changes as ci
ii. total number of code churns as di

Study Design: Interpretation of Values
 Interpreting the effect sizes
 Interpreting the p-values

RQ1: What is the relation between service patterns
and change-proneness?

H1
01 : there is no difference between the total number of changes experienced
by files involved in the implementation of a service pattern and other files
H2
01 : there is no difference between the total number of code churns
experienced by files involved in the implementation of a service pattern and
other files

H1
01 : there is no difference between the total number of changes experienced
by files involved in the implementation of a service pattern and other files
H2
experienced by files involved in the implementation of a service pattern and
other files
SODOP
Measure
change-proneness
Test H1
01 &H2
01
(Wilcoxon rank sum test)

Findings RQ1: Patterns are less change-prone but
not at (statistically) significant level

RQ2: What is the relation between service

H1
02: there is no difference between the total number of changes experienced
by files involved in the implementation of a service antipattern and other files
H2
experienced by files involved in the implementation of a service antipattern and
other files

H1
by files involved in the implementation of a service antipattern and other files
H2
experienced by files involved in the implementation of a service antipattern and
other files
SODA
Measure
change-proneness
Test H1
02 & H2
02

Findings RQ2: Antipatterns are more change-prone
at the statistically significant level
15 of 21

15 of 21
Findings RQ2: Antipatterns are more change-prone
at the statistically significant level

RQ3: What is the relation between particular kinds
of service antipatterns and change-proneness?

H1
by files from groups (GAi)iє{1,….8} and GNoAP
H1
03: there is no difference between the total number of code churns
experienced by files from groups (GAi)iє{1,….8} and GNoAP

H1
by files from groups (GAi)iє{1,….8} and GNoAP
H1
03: there is no difference between the total number of code churns
experienced by files from groups (GAi)iє{1,….8} and GNoAP
16 of 21
SODA
Measure
change-proneness
Test H1
03 & H2
03
(Kruskal-Wallis test)
Classify source files
(antipatterns vs non-antipatterns)

Findings RQ3: Antipatterns (investigated in this
study) are not equally change-prone
17 of 21

17 of 21
Findings RQ3: Antipatterns (investigated in this
study) are not equally change-prone

Confounding Impact:
Are service antipatterns more vulnerable to OO
code-level smells (and vice-versa for service pattern)?

Confounding Impact:
Are service antipatterns more vulnerable to OO
code-level smells (and vice-versa for service pattern)?
SODA
SODOP
Compare the groups
Classify source files
(patterns vs. non-patterns)
(antipatterns vs. non-antipatterns)

Findings on Confounding Impact
19 of 21
 Service antipatterns contain more (but not statistically significant) code smells
 Service patterns contain less code smells at the statistically significant level

Take Home Message…
• Developers should avoid implementing Service
Antipatterns to
- reduce maintenance efforts and costs, and
- improve maintainability and ease evolution
• Implemented service patterns have less code-level
OO smells

Conclusion

Future Work
• Future works include
- replicate the study on other SBSs and service antipatterns
- investigate the changes types and their impact on antipatterns
- investigate the relation between service antipatterns
and fault-proneness

Investigating the Change-proneness of Service Patterns and Antipatterns

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