Deutscher Wetterdienst

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Deutscher Wetterdienst
The NinJo Client Framework Sibylle
Haucke Deutscher Wetterdienst Sibylle.Haucke_at_dwd.d
e
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The NinJo Client FrameworkOverview

• NinJo (Common Graphics System) Client -
  Requirements And Solutions
• MVC And PAC - A Simple Introduction
• PAC - Agents In NinJo
• PAC - The Framework
• PAC - How To Create a New Layer ?

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NinJo Client Important Requirements

• User Requirements
• provide all capabilities of older systems (MAP,
  GeoBert, IGS, SWC) in one
• heavily interactive
• nevertheless easy to use, intuitive user
  interface
• effective, safe and quick to use
• Developer/project Requirements
• expandable, easy to maintain
• portability
• country and language independency
• capability to configure various workplaces
• to be built by distributed teams with long
  distances to each other
• build working environment for each team member to
  take advantage of his capabilities and
  experiences (e.g. RADAR expert , SAT image
  expert, analysis expert)

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The NinJo ClientCan we live up to our customers
expectations

• It seems to be not solvable
• We started with the analysis of the existing
  systems
• their advantages and disadvantages from user side
• kinds of presentation of meteorological data
• different kinds of user interaction
• requirements on products to be produced
• experiences with maintenance
• Then we begun to design lookfeel of GUI
• We could identify tasks for different modules of
  the future software

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NinJo Client Example-MAP-Software
NowcastingObservation DataSatellite ImageModel
Field
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NinJo Client Solutions Layer For Presentation

• We realised that all kinds of presentation in
  geographical area need layers
• Idea of a Layer-Framework
• each (presentation) layer is responsible for one
  kind of data, for example
• surface observation (SYNOP, SHIP, METAR,..)
• radar imagery
• satellite imagery
• geography (several layers for coasts, rivers,
  borders, towns, orography)
• model fields (isoline)
• aerological (FM35)
• nowcasting
• lightning data ...

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NinJo Client Solutions Layer 2

• Layer-Framework
• Each layer can process events and holds its own
  data
• Layers have common and special behaviours
• Layers must be combined in one window (Canvas)
• We need a mechanism to manage layers, process
  events and user actions
• Design of the Layer Framework

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NinJo Client Conclusions Programming
Environment

• We have to construct an open architecture to make
  the system expandable
• Design modular software with clear distribution
  of responsibilities
• Object oriented design gives possibility to build
  expandable, well structured software
• Object oriented techniques are very suitable for
  solving such a problem
• Early decision
• pure Java Application
• Graphics based on Java 3D / Java 2D
• Use design patterns for reusable software modules
  

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Overview

• NinJo Client
• MVC And PAC - A Simple Introduction
• PAC - Agents In NinJo
• PAC - The Framework
• PAC - How to Create a New Layer ?

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MVC And PAC Design Patterns What is that?

• A Design Pattern is a solution to a multiply
  recuring problem in OO software design
• Patterns collect solutions, that were found
  during software development all over the world
• To handle the problems and their solutions as
  patterns, make it easier to recognize problem
  situation and solve it.
• Using design patterns makes the software more
  reusable, more flexible, more modular.
• The Gang of Four has collected and described
  important design patterns 1
• Now we could look for a suitable design pattern
  and found the PAC paradigm, a hierarchical
  Model-View-Controller MVC
• Literature 1 Gamma,Helm,Johnson,Vlissides
  Design Patterns, Addison Wesley 1995

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MVC And PAC MVC- Pattern Model, View, Controller

• Model
• holds application data
• can have several views and informs them of any
  data changes

actualise
actualise
Model

• Views
• visualise data on screen
• get data from model

View1
View2
getData
getData
modify
Controller

• Controller
• controls gui
• receives events
• provides possibilities for handling the user
  inputs
• controls model and view

modify
modify
events
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MVC And PAC PAC - Presentation/Abstraction/Contro
l

• PAC paradigm, a hierarchical Model-View-Controller
  MVC
• Abstraction (Model) - a logical model of the
  problem.
• Presentation (View) the screen representation of
  the complete or of a special part of the model.
  Views can be nested, allowing a view of
  high-level to comprise views of its subsystems.
• Control (Controller) defines how the UI reacts
  to user input.
• In an event-based system, it's the controller
  that catches any fired events.

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Overview

• NinJo Client
• MVC And PAC - A Simple Introduction
• PAC Agents In NinJo
• PAC - The Framework
• PAC - How to Create a New Layer ?

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PAC Agents MVC Triples In NinJo

• NinJo Client consists of a tree of MVC triples,
  called PAC Agent
• These agents are used like GUI components
• Hierarchy of agents as aggregation represents
  the GUI
• Build different NinJo (DWD, MeteoSWISS, GeoPhys,
  DMI ) clients with a building kit

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PAC Agents MVC In NinJo

• PAC agent hierarchy in NinJo
• models hold raw data
• views can be nested
• controllers map the hierarchy of the agents as a
  tree
• control flow always goes along the controllers
• Objectives of the PAC framework design
• configurability of agent-hierarchy (XML)
• configurability of representation of an agent
• strict decoupling of agents

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PAC Agents Identify Agents In GUI
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PAC Agents Composition Of View Components

• Lower views provide to compose into higher
• component (for instance JPanel)
• menu, optional
• toolbar, optional
• graphical objects (GOF-Layer, visualising
  meteorological data)
• Higher view actively integrates the delivered GUI
  components into itself
• Lower view retains control about the delivered
  GUI components
• Client is composed with a building kit (like
  LEGO)

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PAC Agents Composition Of View Components
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Overview

• NinJo Client
• MVC And PAC - A Simple Introduction
• PAC Agents In NinJo
• PAC - The Framework
• PAC - How Creating A New Layer ?

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PAC Framework The Layer Architecture

• What is a Layer Architecture ?
• Layer Architecture strong rules of how to
  create a layer in NinJo.
• Why a Layer Architecture ?
• uniform design
• less cost of teaching
• less complexity
• simpler documentation
• better quality of design
• helps to create reusable components

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PAC FrameworkThe Layer Architecture

• GOF basic graphic methods, abstracts from
  Java2D/3D
• VisLib higher level visualisation techniques
  independent from concrete data
• Layer different abstractions or technical level
  of visualisation of meteorological data
• Layer Data Model deals with specific details of
  particular kind of data
• Access Layer access to server objects
• Layer Framework control of course, vertical to
  the layers

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PAC Framework Base Classes

• Base classes are abstract, so they cannot be used
  without derivation
• They contain all common functionality of agents
  and so the programmers of agents are relieved of
  the implementation of basic functionalities.
• Following capabilities are completely provided
  by the PAC-framework
• building of controller-hierarchy (methods and
  attributes for the parent- child-relation),
• shared models

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PAC Framework The Layercontainer

• The LayerContainer controls all common
  functionality of activating and visualising
  layers.
• Following capabilities are completely provided
  by the LayerContainer
• visualising a set of layers
• geographical projections and map areas
• zooming, panning
• date
• switching layers on/off
• arranging legends
• interaction with mouse
• updating layers

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Overview

• NinJo Client
• MVC And PAC - A Simple Introduction
• PAC - Agents In NinJo
• PAC - The Framework
• PAC - How to Create a New Layer ?

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PAC Framework - How to Create a New Layer ?

• 7 Steps To Create A New Layer Agent
• Design the data classes for effective storing of
  data
• Design classes for a specific visualisation using
  
• common visualisation classes and GOF classes
• Derive from basic PAC classes to create a new
  kind of PAC (Layer-) agent with model, view and
  controller
• Use the new specific data classes inside the PAC
  model
• Derive from basic GUI classes to create the menu
  of the new kind of data
• Develop specific GUI-elements like Toolbar,
  Dialog boxes
• Extend the client configuration file to integrate
  the new Layer Agent into NinJo client by
  inserting a tag for the new BottomLevel Agent

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Conclusions What do you need to create a new
2D-visualisation layer
NinJo PAC (Layer) Framework including
LayerContainer and GOF the building kit
The rules of Layer Architecture
A Layer Team some people, well familiar with OO
and JAVA
One-Week-Course
Last, but not least A good idea of What your
layer shall do ?
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Overview

• NinJo Client
• MVC And PAC - A Simple Introduction
• PAC - Agents In NinJo
• PAC - The Framework
• PAC - How Creating A New Layer ?