AOP/cross-cutting

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AOP/cross-cutting

• What is an aspect?

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What is an aspect?

• An aspect is a modular unit that cross-cuts other
  modular units.
• What means cross-cutting?
• Apply AOP to AOP. Tease an aspect apart into
  three units ideal graph, labels on nodes and
  edges of ideal graph, application to concrete
  graph using connectors specifies cross-cutting

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Example ACs

• Ideal graph participant graph
• Labels on nodes and edges participant code
• Concrete graph participant graph or application
  class graph
• Connectors specify cross-cutting

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Theory of cross cutting

• Model programs as graphs (e.g. class diagrams,
  abstract syntax trees, etc.)
• Aspects model as graph editing instructions
  modeled with respect to an ideal graph.
• Graph editing add new nodes and edges and add to
  node labels and edge labels

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Specifying cross-cutting

• Uniform node to nodes, edge to edges simple
  weaving
• explicit A,B,C,D
• succinct Nodes(Graph(From A to D))
• Non-uniform edge to multiple edges code is
  different from target edge to target edge

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Open-Closed Principleapply to aspects?

• A satisfactory modular decomposition technique
  should support modules that are both open and
  closed.
• A module is open if it is available for extension
• A module is closed if it is available for use by
  other modules

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Static model with behavior
Scheduler
sessions
instructors
courses


instructor 0..1
Course
Session
Instructor
sessions

duration Duration
rating Grade free(Date,Date)
sessions

start Date end Date confirmed
Boolean overlaps( Session)
course
Static model


qualifiedFor
qualifiedInstructors
Invariant (business rule) inv Instructorqualifi
edFor-gtincludesAll(sessions.course) inv Session
confirmed gt instructor ltgt null and end
startcourse.duration
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Minimal specification

• Action Schedulerchange_dates
• (Session s, Date d)
• pre s.start gt now and (1)
• s.courseltgtnil and (2)
• s.course.duration Days (3)
• post s.start d (4)
• s.end d course.duration (5)

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Minimal specification

• Action Schedulerchange_dates
• (Session s, Date d)
• pre s.start gt now and (1)
• /pre s.courseltgtnil and (2)
• s.course.duration Days (3)
• post s.start d (4)
• /post s.end d course.duration (5)

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Which parts are needed?

• 1, 4