Identification of Crosscutting in Software Design

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Identification of Crosscutting in Software
Design

• Klaas van den Berg University of Twente
• José María Conejero University of Extremadura
• Juan Hernández University of Extremadura

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• CC ! S T
• Problem statement
• CC

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Context Motivation
AOSD
many solutions! what is the problem?

• Steps
• Define crosscutting
• Identify crosscutting
• Quantify crosscutting
• Resolve crosscutting

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Concept Diagram
operationalization
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Definitions

• Crosscutting
• the tangling and/or scattering of concerns
• Scattering
• the spreading of a concern to multiple modules
• Tangling
• the intermixing of multiple concerns in a module
• Aspect
• a concern that crosscuts an artifacts
  decomposition
• CC ! S T
• Needed operationalization CC

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Outline

• Crosscutting pattern
• definitions of scattering, tangling and
  crosscutting
• change impact analysis
• Representation
• dependency graph
• dependency matrix crosscutting matrix
• Application
• change impact analysis / examples / case studies
• cascaded crosscutting pattern
• extended crosscutting pattern
• Open issues

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Crosscutting Pattern
source and target
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Examples

• source and target are abstractions from
• specific phases, levels, layers, domains,..

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Crosscutting Pattern

• Pattern recurring problem and reusable solution
• Concepts source and target are taken from MDA
• However, no automated transformations are
  assumed!

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Crosscutting
Elements involved both in scattering and tangling
s3 crosscuts s4
s5
source
s3
s1
s4
s2
tangling
scattering
target
t5
t2
t1
t3
t4
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Crosscutting

• Crosscutting
• a source element is scattered over target
  elements and where in at least one of these
  target elements, multiple source elements are
  tangled
• s1 crosscuts s2
• source element s1 crosscuts source element s2 for
  a given mapping between source and target, if s1
  is scattered over target elements and in at least
  one of these target elements, s1 is tangled with
  source element s2
• s1 crosscuts s2 with respect to a mapping to and
  decomposition of the target

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Change Impact Examples

• Scattering change s5 gt impacted t4, t5
• Tangling change s1 gt impacted t1, s2
• Crosscutting change s3 gt impacted t2, t3, s4

s5
s3
s1
s4
s2
Propagation of change impact across multiple
levels
to be preserved
t5
t2
t1
t3
t4
Dependency graph
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Change impact

• change element v in the mapping (x,v)
• impact(x,v)
• change(x,v)
• (preserve(u,v) u ? preds(v) x ? v)
• (impact(v,w) w ? succs(v))
• preds predecessors of an element
• adjacent elements in backward trace
• succs successors of an element
• adjacent elements in forward trace

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Representation

• Dependency graph
• node elements in source and target
• edge dependency relation between source target
  elements
• Dependency matrix
• source x target
• cell dependency relation between source target
  elements
• Crosscutting matrix
• source x source
• cell crosscutting relation between source
  elements

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Crosscutting
source s1, s2, s3
Example
s3
s1
s2
s1 crosscuts s3
dependency graph
t2
t1
t4
t3
target t1, t2, t3, t4
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Matrices

• s1 crosscuts s3

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Mathematics

• Dependency matrix source x target
• Scattering matrix source x target
• Tangling matrix target x source
• Crosscutting product matrix source x source
• crosscutting product matrix
• scattering matrix x tangling matrix
• matrix multiplication
• Crosscutting matrix source x source
• normalized crosscutting product matrix

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Case Studies

• DVD System
• Gradecki Lesiecki
• Logging
• Dialog system in GUI
• Mediator Pattern
• Drawing editor
• Adapter Pattern

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Across Life Cycle

• Consecutive levels or phases
• Traceability links between phases
• (e.g. concerns, requirements, architecture,
  design,..)
• Approach
• Cascading of crosscutting pattern
• Transitivity of dependency relations
• Matrix multiplication of dependency matrices

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Extended Crosscutting Pattern

• Transitivity of inter-level and intra-level
  dependencies

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Evaluation

• Identification of Crosscutting
• Crosscutting pattern
• Based on inter-level dependencies
• Definitions of tangling, scattering and
  crosscutting
• Formalization
• Matrix representation and matrix operations
• Operationalization of tangling, scattering and
  crosscutting
• Across consecutive phases
• Cascading of crosscutting pattern
• Extended crosscutting pattern
• Based on inter-level and intra-level dependencies

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Open Issues

• Elements in source and target
• granularity of decomposition
• composites (vs atomic elements)
• Dependency relations
• inter-level dependency types
• intra-level dependency types
• directionality and transitivity of relations
• Change impact in case of crosscutting
• number of changes (delete, add, modify)
• severity of changes (effort)
• Validation scalability in case studies
• Tool support