Presented by Andrs Daz Pace

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Composing Modeling Frameworksin CATALYSIS

• CHAPTER 19
• Presented by Andrés Díaz Pace
• April 2000

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Overview

• Introduction to reuse with frameworks
• Extending the framework notion in Catalysis
• An example
• Composing generic models and specifications
• Main concepts in Catalysis
• Types
• Refinements
• Collaborations
• Frameworks
• The complete picture
• Summary

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Introduction

• Reusable artifacts
• pieces of code
• models
• specifications
• interactions
• refinements
• Essence of a design ?
• Collaborations and relationships between elements
• Framework notion It is generalized to object
  modeling and specification activities, permitting
  construction of specifications and design models
  by composition (Catalysis).
• UML compliant
• Component-based and Framework-based development

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Frameworks - Beyond OOP

• An OO framework is often characterized as a
  set of abstract and concrete classes that
  collaborate to provide the skeleton of an
  implementation for a given set of applications
• A framework should be ADAPTABLE

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Catalysis goals

• Apply frameworks-like techniques to the
  modeling, specification and implementation of
  systems in a methodical way.

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An Example

• A service company that delivers seminars
• Allocation for instructors and facilities to a
  seminar
• On-time production of seminar materials for
  delivery
• Targeted marketing of seminars
• Invoicing and accounts receivable
• How can these operations be decomposed in
  relatively orthogonal aspects ?

Operations
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Composing generic specifications and models

• Conceive abstract specifications of each aspect
  of the problem
• Library of reusable abstract specification
  components
• Problems to be solved
• Framework descriptions must be abstract. We can
  be able to substitute domain terms into the
  generic concepts provided by the framework
• The generic models must be precise. This permit
  meaningful manipulation when composed.
• Ways to hook the frameworks together in a
  particular composition.
• Different levels of detail in the description.
  Refinement.

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Resource Allocation (1)

• // For any job, only allocate resources that meet
  the requirements of the job
• inv jJob, j allocated ! Null ?
  (j.allocated.provides.meets(j.requires))
• action allocate (rResource,jJob) post // Spec
  of allocate operation
• action confirm(jJob) post // Spec of
  confirming a job
• action complete(jJob) post // Spec of
  completing a job

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Resource Allocation (2)

• The Resource allocation framework can be mapped
  to different concrete situations assigning cars
  to renters, instructors to rooms, jobs to
  machines, videos to club members, etc.

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Main Concepts in Catalysis

• Types
• Abstracting behavior using type models
• Refinements
• Explicitly mappings between levels of
  abstraction.
• Collaborations
• Abstract joint behaviors and dialogs
• Frameworks
• A foundation for design composition and reuse

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Types and classes

• A type is an external view of (some interesting
  aspects of) the visible behavior of some set of
  objects.
• A type names an interface
• A type is not the same that a class
• A type does not specify implementation
• A class implements a type, making its own
  implementation decisions.

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Actions, Roles and Collaborations

• A collaboration defines a set of actions between
  typed objects playing certain roles with respect
  to other objects in that collaboration. A
  collaboration may be refined by a more detailed
  set of actions

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Frameworks with Placeholders

• Every object plays multiple roles in many
  collaborations.
• Each collaboration partially defines the joint
  behaviors of some sets of objects.
• A framework defines patterns in generic terms by
  utilizing placeholders for elements. It can be
  applied to a family of related types with
  appropriate substitutions to generate different
  models and designs.
• A model
• A group of models for a collaboration
• A static relationship between objects
• A single type
• A class
• A package of related classes

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Subject-Observer pattern (1)

• The state of the observer is some function
  project of the state of the subject.

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Subject-Observer pattern (2)

• A telephony application using the
  Subject-Observer pattern

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Framework composition

• From a partial framework application a tool could
  automatically generate the resulting model,
  including all the invariants and behaviors

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Summary

• Catalysis generalizes the concept of frameworkto
  object modeling and specification activities.
• Specification and design models by composition.
• A tool could automatically generate a final
  model with specific details.
• For more information
• DSouza99 DSouza, D., and Wills, A. Objects,
  Components, and Frameworks with UML The
  Catalysis Approach. Object Technology Series.
  Addison-Wesley. 1999.
• UML99 Unified Modeling Language, Version 1.3,
  http//www.rational.com/uml
• Gamma94 Gamma, E., Helm, R., Johnson, R., and
  Vlissides, J. Design Patterns, Addison-Wesley,
  Reading, Massachussetts 1994.