The Next Generation Messaging
Technology
- Makes Web Services Effective
Maria E Orlowska
The University of Queensland
School of ITEE
Australia
Overview
•
•
•
•
•
Process oriented computing,
Issues with BPM (Business Process Management),
WS (Web Services) – a new promise,
Why it is hard to deploy WSs,
Will HMT (Harmonising Message Technology) – a
smart messaging help ?
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Process meets Technology
• Could web services live up to their promise and spell
the end of integration dramas forever?
– Several success stories already reported,
– Web services standards around collaborative capabilities of
UDDI (Universal Description, Discovery and Integration)
WSDL ( Web Services Description Language) and
SOAP (Simple Object Access Protocol) which respectively
catalogue, describe and publish the various Web services
offered by a service provider,
– Web services should hide the complexity of business processes
and focus on getting data flow as efficiently and simply as
possible,
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‘It is a massively complex undertaking and the
devil is literally in the detail’
David Clarke, Managing Director, Webjet
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4
Process-Oriented Computing
Process
Logic
Business
Process
Management
Configure,
Coordinate,
Collaborate,
Integrate
Presentation
Logic
User
Interaction
Business
Logic
Data
Logic
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Application
Services and
Components
Execute
Database
Management
Persist
Present,
Interact
5
Process-Oriented Computing
Process
Logic
Business
Process
Management
Configure,
Coordinate,
Collaborate,
Integrate
Presentation
Logic
User
Interaction
Business
Logic
Data
Logic
APWeb’04 – April 04
Application
Services and
Components
Database
Management
Execute
Present,
Interact
Persist
Focus of Business
Process Modeling and
Management
6
Process-Oriented Computing
Process
Logic
Business
Process
Management
Configure,
Coordinate,
Collaborate,
Integrate
Presentation
Logic
User
Interaction
Business
Logic
Data
Logic
APWeb’04 – April 04
Application
Services and
Components
Database
Management
Execute
Present,
Interact
Persist
Focus of Application
Development
7
Process-Oriented Computing
Process
Logic
Business
Process
Management
Configure,
Coordinate,
Collaborate,
Integrate
Presentation
Logic
User
Interaction
Business
Logic
Data
Logic
APWeb’04 – April 04
Application
Services and
Components
Database
Management
Execute
Present,
Interact
Persist
Focus of processoriented application
development and
deployment
8
Key issue - Separation of Process Logic
WFMS
Process
Logic
Process Logic
Process Logic
Application
Logic
Data
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Application
Logic
DBMS
Data
Application
Logic
DBMS
Data
9
Wfs - Current Computational Model
• Isolation of process logic triggers;
– User initiated flow - reflecting activity/task progress
– Workflow engine initiated flow- reflecting process progress
Activity
Activity
Activity
Activity
Activity
Activity
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Wfs - Current Computational Model (cont)
• Each task has predefined, generic FSM,
– Creates difficulty to map activity logic to engine readable
states,
– Provides a strict meaning of the process flow,
• Simplicity for the price of restrictions,
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Activity Execution
User level
Activity
Process Model level
Complete
Allocate
Completed
Active
Scheduled
Abort
Recall
Terminated
Workflow Engine level
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Process Execution
Activity
Activity
Complete
Allocate
Completed
Active
Scheduled
Completed
Active
Abort
Abort
Recall
Recall
Terminated
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Complete
Allocate
Scheduled
Terminated
13
Instances Execution
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Impossible Instances Execution -
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End to End Process Management (Example)
Create
Purchase
Request
Create
Purchase
Order
Send
Purchase
Order
Receive
Goods
Receive
Invoice
Send
Payment
Process
Application Services
Purchase
Request
Service
Purchase
Order
Service
Shipment
Notice
Service
Payment
Service
Application Database
Database
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BPM, Application Services, and Data Model (N – M)
Create
Purchase
Request
Create
Purchase
Order
Purchase
Request
Service
Send
Purchase
Order
Receive
Goods
Purchase
Order
Service
PR
N
M
Receive
Invoice
Shipment
Notice
Service
PO
N
M
SN
Send
Payment
Payment
Service
N
M
INV
1
1
1
1
N
N
N
N
PR I
N
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M
PO I
N
M
SN I
N
M
INV I
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Process Modeling
Create
Purchase
Request
Create
Purchase
Order
Send
Purchase
Order
PO 1
A 50
B 30
PR 1
A 20
B 30
C 20
PO 2
C 10
D 10
PR 2
A 30
D 10
E 15
PO 3
C 10
E 15
Receive
Goods
SN 1
A 50
B 30
C 10
Receive
Invoice
Send
Payment
INV 1
A 50
B 30
C 10
D 10
SN 2
D 5
SN 3
D 5
INV 2
C 10
E 15
SN 4
C 10
E 15
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Process Modeling
Create
Purchase
Request
Create
Purchase
Order
Send
Purchase
Order
PO 1
A 50
B 30
PR 1
A 20
B 30
C 20
PO 2
C 10
D 10
PR 2
A 30
D 10
E 15
Item C is no
longer required
and is cancelled
on the purchase
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request
PO 3
C 10
E 15
Receive
Goods
SN 1
A 50
B 30
C 10
Receive
Invoice
Send
Payment
INV 1
A 50
B 30
C 10
D 10
SN 2
D 5
SN 3
D 5
INV 2
C 10
E 15
SN 4
C 10
E 15
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The HMT Concept
• A technology allowing messages coordination from
multiple parties,
• Some characteristics:
– It should be easy to use – minimal technical skills required to set
up a collaboration,
– It should be easy to join (leave) the collaboration arrangement,
– Rich and extensible language to specify relationships between
messages,
– Provide a natural subsumption of workflows-like collaboration,
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Functionality
• HMT supports:
– Checking the message template for completeness and
authentication (check)
– Storing the message persistently (store),
– Evaluate specified collaboration rules (evaluate) with resulting
one of the functions:
1. Create a new instance of a msg template (create),
2. Send a message (send),
3. Store for re-evaluation (delay),
4. Accept transaction (transac)
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Collaboration Space
• Massage harmonization is defined within a Collaboration
Space,
• A Collaboration Space (CS) consists of:
– Registered Partners (security issues, who is allowed to
participate)
– Set of message templates ,
– Set of rules (temporal first order logic in terms of message
attributes)
• Only one create function is expected to be applied before
send,
• CS deals with many “single steps” to form the overall
collaboration,
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Message Template
• Each Message Template (MT) has it’s XML schema,
• Several functional parts can be distinguished;
– Scheduling attributes such as CS_id, MT_type_id, instance _id
(optional)
– Content structural attributes (those which forms terms in rules
specification),
• Attributes can be mandatory and optional,
• Other constraints
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Rules Specification
• Each rule LHS is an expression (temporal first order
logic expression) with literals being attributes of MTs
from that CS,
• Each rule RHS is a HMT function either
create (MT) followed by send (MT) or send (MT)
• Rules may be in conflict and not leading to a unique
action – need for methods for design and verification,
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Further issues for MT and Rules
• Those two entities must be tightly “integrated”,
• One framework for design and specification – systems
completeness:
– Each rule is supported (LHS and RHS),
• Impacts of modifications either rules or MTs
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Collaboration Space in Messaging Service
Collaboration Space
Incoming Message
Instances
Senders
S01
Message
Transformation
Rules
Outgoing Message
Instances
MT08.I001
MT08.O001
MT01.I002
MT06.O001
Receivers
R01
S02
R02
S03
MT01.I003
MT06.O002
MT02.I001
MT07.O001
MT03.I001
MT09.O001
MT03.I002
MT06.O003
MT04.I001
MT07.O002
MT05.I001
MT08.O002
R03
S04
R04
S05
R05
Message Templates
MT01
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MT02
MT03
MT04
MT05
MT06
MT07
MT08
MT09
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Message-Oriented BPM using Harmonization
Messaging Service ensures that A, B, C, and D are performed in the right order
as well as only messages are used to communicate with BPM Objects. This is
the goal of the HMT invention. The HMT would provide a SINGLE platform to
manage both coordinative and collaborative communication.
Messaging
Service
A
B
BPM Object X
C
D
BPM Object Y
Outgoing Messages
Message
Templates
Message
Handler
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Incoming Messages
Public Methods
Outgoing Messages
Message
Templates
Message
Handler
Incoming Messages
Public Methods
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Challenges
• Requirements for HMT:
–
–
–
–
Traditional Wf model must be a special case,
Simple graphical language to specify the rules,
Process modelling shouldn’t be harder,
Validation and verification methods should assist with
specification,
– Process monitoring and transactional behaviour
should be guaranteed,
– The model should formally capture Wf integration,
– Scalability for process-intensive environments,
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Concluding Remarks
Promise:
• HMT offers flexible service composition,
• HMT is applicable to communicating active RFID devices,
Status: first demo scheduled for Nov 2004 at SAP Future
Scope event, Germany,
More Info: http://www.itee.uq.edu/~dke
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