CHAPTER 12: APPLICATION AND COMPONENT INTEGRATION 11:35 2 - - PowerPoint PPT Presentation

CHAPTER 12: APPLICATION AND COMPONENT INTEGRATION

Architecture and Modelling

• f Information Systems (D0I71A)
• Prof. dr. Monique Snoeck

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Application integration

• What if you already have software ?
• Software manages its own business objects
• Software offers services per business objects
• If you have several software applications
•  same business object may appear in several applications

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E-learning Platform ERP system Planning Software Student Teacher Course Budget Schedule Course Document Invoice Assignment Room

Shared objects require coordination

• Each individual application manages its own data
•  business objects + their methods = 1 column of OET
• Coordination across applications is missing

 can be achieved based on “events”

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Course document Assignment Student-1 Course-1 Teacher-1 Student-2 Course-2 Teacher-2 Room-2 Budget Invoice Course-3 Teacher-3 Room-3 Schedule cr_student

x x

end_student

x x

cr_course

x x x

end_course

x x x

cr_room

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end_room

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cr_schedule x cr_assignment x E-learning platform ERP system Planning Software

Component-event table

• OET becomes CET

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(Recap) A Business Event is ...

• A request to perform an activity to register something that happens or that

you would like to happen in the real world.

(c) Monique Snoeck

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(Recap) Business Event Handling

1. Tasks Event Dispatcher

• Check Preconditions of all participants
• By Event Dispatcher
• By rule engine
• By Objects/Components
• Notify Event (broadcast) to participants
• Co-ordinate answers
• Check first – do then
• Do & compensate

2. How many Event Dispatchers ?

• Centralised versus Distributed
• ne event handler for all events (maximally centralised)
• ne event handler per event (maximally distributed)

(c) Monique Snoeck 30/03/2020

(Recap) Event Broadcasting

• Event handler coordinates the handling of
• ne event across 1-many participant(s)

(c) Monique Snoeck 30/03/2020

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Event

PRODUCT TYPE PRODUCT ORDER ORDER LINE

modify_quantity

Modify Quantity

Check modify quantity

Done Done Done Done

modify quantity

Done Ok Ok Ok Ok

E-learning Platform ERP system Planning Software Student Teacher Course Budget Schedule Course Document Invoice Assignment Room

Application Integration

• CASE 1: Intra-enterprise integration layer with Enterprise Layer
• Enterprise layer used to handle information sharing between different

components

Application Integration, Case 1

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New Input Services Event Handling Layer New Output Services Domain Layer Off-the- shelf Software 2

1 1 2 2

Off-the- shelf Software 3

4 5 2

Off-the- shelf Software 1

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event handler

3

Application Integration

Architecture services:

1.

Off-the-shelf software can inspect the state of business objects (= regular output services).

2.

Off-the-shelf software uses the services of the event handlers to trigger business events whenever it wishes to update business objects in the enterprise layer (= regular input service).

3.

OR The event handler ‘listens’ to detect the occurrence of a business event in the Off-the-shelf software application.

4.

The event handler notifies business events to the business objects residing in the enterprise layer.

5.

Off-the-shelf software can subscribe to the corresponding event handler in order to be notified upon occurrence of the event.

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Application Integration

• CASE 2: Integration of Distributed (loosely coupled) Components
• The enterprise layer may itself be distributed among multiple components,

applications or web services, possibly developed and controlled by different authorities.

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Application Integration, Case 2

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New Input Services Event Handling Layer New Output Services Domain Layer Off-the- shelf Software 2 Off-the- shelf Software 3 Off-the- shelf Software 1 event handler Domain Layer Domain Layer

Application Integration

• CASE 2: Integration of Distributed (loosely coupled) Components
• The enterprise layer may itself be distributed among multiple components,

applications or web services, possibly developed and controlled by different authorities.

• Existing components  see architecture case 1
• New Components  develop with layered architecture
• Internal domain layer
• Internal event handling layer
• IS-layer:
• Event triggering interface
• Event listening interface
• Object Inspection interface

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Integration of Distributed Component

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Local Enterprise Layer Local Event Handling Layer

component with other internal structure

Global Event Handling Layer

Event triggering interface Object inspection interface Event triggering interface Object inspection interface Event invocation interface Event listening interface

Event handling Architecture

• With Publish-Subscribe Architectures
• To be combined with coordination protocol
• No ‘fire & forget’
• Different precondition verification patterns
• Centralised (e.g. in event handler)
• Distributed
• Allows for dynamic run-time management of the CET
• New components can publish new types of events to which existing components

can subscribe

• New components can subscribe to existing types of events

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Calculated at design time

• r

at run-time (upon subscrition of new components)

SUPPLIER PRODUCT ORDERLINE ORDER CUSTOMER 1 * 1 * 1 * 1 * SUPPLIER-WS CUSTOMER-WS

Contract Management Capabilities

Application Integration

• Use of Enterprise Layer avoids problems associated to data replication
• Coordination is simplified by the introduction of event handlers
• Dynamic integration possible with use of publish-subscribe architectures

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