Transcript Enterprise Application Integration

Enterprise Application
Integration
Walter Moerkerken
Ilona Wilmont
Integratie Software Systemen
8 mei 2006
Today’s topics
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Evolution of software architecture
Middleware and EAI
Message Brokers
EAI with message brokers
Publish/subscribe model of interaction
History Workflow Management systems
WfMs`s
WfMs als programmeertaal
Conclusions
Evolution of software
architecture
Information system design
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Presentation layer
- communication with other entities
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Application logic layer
- actual operation
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Resource management layer
- data to work with
Architectural design
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Information systems are composed of
several layers, or tiers.
One-tier architectures
Two-tier architectures
Three-tier architectures
N-tier architectures
Middleware and EAI
Middleware
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Interaction between applications
across heterogeneous platforms
Solution to integrating set of servers
and applications under a common
service interface
Basic infrastucture behind distributed
information system
Enterprise Application
Integration
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Extends middleware capabilities to
cope with application integration
Uses application logic layers of
different middleware systems as
building blocks
The supply chain
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Customer request
- Querying company
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Order processing
- Analysis and verification purchase order
- Scheduling manufacturing of goods
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Order fulfillment
- Delivery to customer
- Financial issues
Difficulties
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Different operating system
Support for different interfaces and
functionality
Different data format
Different security requirements
Different infrastructure and interaction
protocols
Message Brokers
Traditional MOM
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Point-to-point links
No support for routing logic
No support for heterogeneity
Sender identifies receiver
Complexity increases as more
applications are added to the system
Message Brokers
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Enhanced MOM-systems
Distribution of messages
Provides flexibility in routing
Filtering of messages
Processing of messages
Adapters for uniform data format
Routing logic moved to middleware
Routing logic
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Based on sender’s identity, message
type or message content
Rule-based language
Message broker level
Queue level
MOM vs. Message Brokers
Message Broker Problems
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No tools provided for debugging and
maintenance
Performance decreases if applicationspecific rules are executed at each
delivery
Inability to handle large messages
EAI with message
brokers
EAI platform components
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Adapters
– map heterogeneous data formats into
common format
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Message broker
– facilitates interaction among back-end
systems
Advantages of message
brokers
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Lower development cost
Lower opportunity costs
Lower maintenance effort
Publish/subscribe
interaction model
Publish/subscribe
overview
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Sender publishes message to
middleware
Receivers subscribe with middleware
to register their interest
Decoupling
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Time
– not actively participating in event at the
same time
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Space
– no references to each other
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Synchronisation
– asynchronous publication and notification
Types of
publish/subscribe
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Topic-based
Content-based
Type-based
Topic-based
publish/subscribe
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Earliest scheme, based on topics
Identified by keywords
Represented as strings
Improvement: hierarchical addressing
– SupplyChain.newPO
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Static scheme with limited expressive
power
Content-based
publish/subscribe
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Based on content of message
Attributes
Meta-data associated with message
Subscribe using subscription language
Specify filters for valid events
– type = “newPO” AND quantity = “1200”
Type-based
publish/subscribe
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Only a suggestion
Filtering messages according to type
Message kind linked to message type
Closer integration of language and
middleware
Workflow Management
Systems
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Geschiedenis
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WfMs`s in chronologische volgorde
– Administrative workflows
– Production workflows
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WfMs`s vs. EAI tools
– Heterogeniteit
– Logica definitie
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Perfecte combinatie
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Wat is een workflow?
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Workflow proces:
– Work Nodes
– Routing Nodes
– Start & Completion
Nodes
– Workflow instantie
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Uitvoering van een
Workflow
Workflow Engine
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Workflow als
programmeertaal
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Variabelen
Uitvoerder van de procedure
Resource regels
Afhandeling van fouten is anders
– Forward Recovery
– Backward Recovery
– Exception-handling Languages
– Deadlines
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Workflow met andere
middleware
Workflow Management
Systems
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Geschiedenis
Wat is een workflow?
Uitvoering van een workflow
Workflow als programmeertaal
Workflows met andere Middleware
Voordelen/Nadelen
Voordelen/Nadelen
Voordelen:
 Snel procesontwerp
 Foutenafhandeling
 Makkelijk te
ondersteunen
Nadelen:
 Een overvloed aan
workflows
 Dure software
licenties
 Complexe installatie
en operatie
 Lange
ontwikkelingsfase
Conclusies
Message broker & Workflow in EAI:
 Message broker
 Workflow modegevoelig
– Lijmen van verschillende systemen
– Bieden (nog) niet wat men verwachtte
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Samenvoeging
Waarom zoekt men nog wel naar iets
anders?