msr asia summit

Yann-Gaël Guéhéneuc

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Some Challenges of Quality Assurance withMulti-language Systems

MSR Asia Summit13/10/28

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Software development services?

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Software costs?

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Cost of bugshttp://www.di.unito.it/~damiani/ariane5rep.html

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Cost of qualityhttp://calleam.com/WTPF/?p=4914

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Maintainability is the ease with which a software system can be modified

—IEEE Standard Glossary of Software Engineering Terminology, 2013

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Agenda

Maintainability– Quality models– Good practices– Social studies– Developers studies

Multi-language Systems Challenges

– Maintainability– Not only for quality assurance!

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Maintainability

Quality Models Models

Good Practices Definition

Metrics

Detection Occurrences

Social Studies Characteristics

Developers Studies Behaviour

Factors

Measures

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Maintainability

Quality Models Models

Good Practices Definition

Metrics

Detection Occurrences

Social Studies Characteristics

Developers Studies Behaviour

Factors

Measures

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Quality model are models with the objective to describe, assess, and–or predict quality

—Deissenboeck et al., WOSQ, 2009(With minor adaptations)

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Quality Models

Basis for quality models – Software measures (aka metrics)– Relationships among characteristics and metrics

• Theoretical• Practical

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Quality Models

Metrics have been well researched– Chidamber and Kemerer– Hitz and Montazeri– Lorenz and Kidd– McCabe– …

(Do not miss Briand et al.’s surveys on cohesion and coupling metrics)

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Quality Models

Different input metrics, different output characteristics– Bansiya and Davis’ QMOOD

• Design metrics• Maintainability-related characteristics

– Zimmermann et al.’s models• Code and historical metrics• Fault-proneness

– …

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Quality Models

Feedback– Measures– Occurrences– Factors

to build “better” quality models

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Maintainability

Quality Models Models

Good Practices Definition

Metrics

Detection Occurrences

Social Studies Characteristics

Developers Studies Behaviour

Factors

Measures

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Important assumptions– That practices can be codified in such a way that

they can be shared between different designers– That reuse will lead to “better” designs. There is

an obvious question here of what constitutes “better”, but a key measure is maintainability

—Zhang and Budgen, 2012 (With minor adaptations)

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Good Practices

We can identifyin the architectureof a systemsmicro-architectures similar todesign motifsto explain theproblem solved

Figure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

To compose objectsin a tree-like structureto describe whole–parthierarchies

Frame

DrawingEditor

Tool

Handle

Panel

DrawingView

Drawing

Figure

AbstractFigure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

Component

operation()

Leaf

operation()

Composite

add(Component)remove(Component)getComponent(int)operation()

ramification

For each componentscomponent.operation()

1..nClient

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Good Practices

We can identifyin the architectureof a systemsmicro-architectures similar todesign motifsto explain theproblem solved

Figure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

To compose objectsin a tree-like structureto describe whole–parthierarchies

Frame

DrawingEditor

Tool

Handle

Panel

DrawingView

Drawing

Figure

AbstractFigure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

Component

operation()

Leaf

operation()

Composite

add(Component)remove(Component)getComponent(int)operation()

ramification

For each componentscomponent.operation()

1..nClient

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Good Practices

We can identifyin the architectureof a systemsmicro-architectures similar todesign motifsto explain theproblem solved

Figure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

To compose objectsin a tree-like structureto describe whole–parthierarchies

Frame

DrawingEditor

Tool

Handle

Panel

DrawingView

Drawing

Figure

AbstractFigure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

Component

operation()

Leaf

operation()

Composite

add(Component)remove(Component)getComponent(int)operation()

ramification

For each componentscomponent.operation()

1..nClient

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Good Practices

We can identifyin the architectureof a systemsmicro-architectures similar todesign motifsto explain theproblem solved

Figure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

To compose objectsin a tree-like structureto describe whole–parthierarchies

Frame

DrawingEditor

Tool

Handle

Panel

DrawingView

Drawing

Figure

AbstractFigure

CompositeFigureAttributeFigure PolyLineFigureDecoratorFigure

Component

operation()

Leaf

operation()

Composite

add(Component)remove(Component)getComponent(int)operation()

ramification

For each componentscomponent.operation()

1..nClient

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Good Practices

Impact of practices– “Good”, such as DPs

• Comprehension by Lange et al.• Quality metrics by Masuda et al.• Change-proneness by Bieman et al. and Khomh et al.

– “Bad”, such as APs• Comprehension by Deligiannis et al. and Abbes et al.• Change-proneness by Khomh et al.• Fault-proneness by Li et al.

Feedback in quality models?

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Maintainability

Quality Models Models

Good Practices Definition

Metrics

Detection Occurrences

Social Studies Characteristics

Developers Studies Behaviour

Factors

Measures

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Social Studies

Developers’ characteristics– Gender– Status – Expertise– Training– Processes– …

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Social Studies

Need for social studies, typically in the form of experiments– Independent variable (few)– Dependent variables (many)– Statistical analyses (few)

– Threats to validity (many)

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Social Studies

For example, impact on identifiers on program understandability– Identifier styles by Sharif et al. and Binkley et al.– Identifier quality by Lawrie et al.– Identifiers styles and gender by Sharafi et al.– …

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Maintainability

Quality Models Models

Good Practices Definition

Metrics

Detection Occurrences

Social Studies Characteristics

Developers Studies Behaviour

Factors

Measures

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Developers Studies

Developers’ thought processes– Cognitive theories

• Brooks’• Von Mayrhauser’s• Pennington’s• Soloway’s

– Mental models• Gentner and Stevens’ mental models

– Memory theories• Kelly’s categories• Minsky’s frames• Piaget’s schema• Schank’s scripts

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Developers Studies

Picking into developers’ thought processes

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Developers Studies

Picking into developers’ thought processes

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Developers Studies

Developers’ thought processes– Reading code by Hansen et al. and Sharafi et al.– Reading design models

• Content by Kagdi et al. and Sharafi et al.• Form by Cepeda et al.

– …

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What’s with today’s systems?

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Multi-language Systems

Today’s systems are multi-languages– Facebook– Twitter– …

– Even your “regular” software system is now multi-language, typically a Web application

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Multi-language Systems

New problems– Different computational models– Complex interfaces (API)– Wrong assumptions– Wrong conversions– …

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Multi-language Systems

For example, control- and data-flows between Java and “native” C/C++ code

native methods in Java are used by Java classes but (typically) implemented in C/C++

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Multi-language Systems

Control-flow interactions– Java code calls native code– Native code calls Java methods– Native code can “throw” and must catch

exceptions Data-flow interactions

– Java code passes objects (pointers)– Native code creates objects– …

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Multi-language Systems

Different computational modelsstatic void *xmalloc(JNIEnv *env, size_t size) {

void *p = malloc(size);if (p == NULL)

JNU_ThrowOutOfMemoryError(env, NULL);return p;

}

#define NEW(type, n) ((type *) xmalloc(env, (n) * sizeof(type)))

static const char *const *splitPath(JNIEnv *env, const char *path) {...pathv = NEW(char *, count+1);pathv[count] = NULL;...

}

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Multi-language Systems

Different computational modelsstatic void *xmalloc(JNIEnv *env, size_t size) {

void *p = malloc(size);if (p == NULL)

JNU_ThrowOutOfMemoryError(env, NULL);return p;

}

#define NEW(type, n) ((type *) xmalloc(env, (n) * sizeof(type)))

static const char *const *splitPath(JNIEnv *env, const char *path) {...pathv = NEW(char *, count+1);pathv[count] = NULL;...

}

No diversion of control flow!

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What challenges?

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Unbalanced focus on “mono”-language systems vs. multi-language systems

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Challenges

Maintainability– Quality models

• Metrics?• Relations?

– Good practices• “Border-line” practices?

– Social and developers’ studies• Independent variables?

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Challenges

Not only for quality assurance!(Just for examples…)

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Challenges

Not only for quality assurance!(Just for examples…)

Build systemsdescriptions

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Challenges

Not only for quality assurance!(Just for examples…)

Build systemsdescriptions

Legal issues dueto interrelations

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Challenges

Not only for quality assurance!(Just for examples…)

Clone definitionand detection

Build systemsdescriptions

Legal issues dueto interrelations

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Challenges

Not only for quality assurance!(Just for examples…)

Clone definitionand detection

Build systemsdescriptions

Legal issues dueto interrelations

Impact on studiesof large systems

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Conclusion

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