Decision Deck Platform Technical Overview

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Decision Deck Platform Technical Overview

• Gilles Dodinet

2nd Decision Deck Dev Days 2008, 3-4 December
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Agenda

• General architecture
• Inside a plugin
• Development

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Agenda

• General architecture
• The whole picture
• Plugin architecture
• Example core model
• Inside a plugin
• Development

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The whole picture
General architecture

• Plugin oriented
• Core
• Plugin manager
• Base features
• Third party plugins
• MCDA methods
• Shared components

Decision Deck Platform
MCDA Plugins
Core
Plugin Manager
Other Plugins
Core Plugins
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Plugin architecture
General architecture

• Bundled as a jar
• Classes (.class)
• Resources
• Images
• Properties files
• Meta information
• Plugin descriptor
• Service descriptor
• Persistent classes

User Interface
Plugin Manager
OSGi
Business Services
Data Access
Hibernate
Model
Legend
depends on
plugin classes
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Core Model Plugin
General architecture

• A few common concepts
• Almost every object is attached (directly or
  transitively) to a Project
• So do plugin model objects

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Agenda

• General architecture
• Inside a plugin
• Data access
• Service layer
• Events
• User interface

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Object persistence
Inside a plugin data access

• Model state stored in MySQL
• Object/Relational Mapping
• Reconcile two views on the same data
• As painless as possible
• Mapping declared using annotations
• Managed connection
• Still need to query the database

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Persisting model objects
Inside a plugin data access

• DAOs built upon Hibernate
• Generic Accessors provided
• Simple CRUD
• A few aggregate functions (count, ..)
• Most of Hibernate complexity is hidden in
  GenericDao and DaoRegistry

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Services
Inside a plugin

• Two  service  types
• Static
• Dynamic
• In both cases strongly typed
• Static services
• Singletons
• Delegates data access to DAOs
• Ex CriterionService.getInstance()
• Dynamic services
• Declared in plugin.xml
• Ex Navigation item providers
• Accessed through PluginManager API

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Model Events
Inside a plugin events

• Plugins can communicate
• Directly
• Through events
• Centralized event management
• Homogenization
• Strongly typed
• Semantics
• Easier debugging

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Handling references
Inside a plugin events

• Fact
• Hibernate imposes strong relational integrity
  (good practice)
• Example
• Criterion does not know anything about
  CriterionRefinement
• Criterion deletion may fail if there exist some
  refinements
• Resolution
• CriterionRefinement provider must register a
  ModelEvent listener to monitor Criterion
  deletions
• Throw VetoException if needed

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User interface
Inside a plugin

• Most of the work involved
• Swing-based
• A few building blocks provided
• Table
• Matrix
• Progress dialog

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Agenda

• General architecture
• Inside a plugin
• Development
• Handling dependencies
• Communicating with D3
• Creating a new plugin

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Plugin dependencies
Development
 plugin  IRIS

• Must be explicitly defined
• MANIFEST.MF
• Require-Bundle
• Example
• Plugin  GLPK  can not see classes from
  plugin  Model 
• Managed by OSGi
• Validation (cycles, missing dependencies, )
• Classloading

 plugin  GLPK
 plugin  DAO
 plugin  Model
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Communicating with D3
Development

• D3
• Distributed Decision Deck
• A web platform to register and execute remote web
  services
• A few D3 features available from D2
• Register a MCDA problem
• Query for the solution
• Delete a problem
• Example Rubis plugin

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Create a new MCDA plugin
Development
Model definition
Data accessors and services definition
Create POJOs
Annotate POJOs
Create DAOs
Create Services
Configuration
Create User Interface
MANIFEST.MF
plugin.xml
persistence.xml
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Eclipse D² Plugin
Development
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Questions