A Metamodel for Enabling a Service Oriented Architecture

Transcription

1 A Metamodel for Enabling a Service Oriented Architecture Baba Piprani, Chong Wang, and Keqing He 1

2 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 2

3 Your presenter Baba Piprani, SICOM Canada Senior IT Consultant with over 30 yrs standardization experience Computer Languages, SQL, Conceptual Schema, Data Modelliing, IRDS, Metadata Registry, MOF Developed award winning implementations of standards-based Data Quality Firewalls for advanced generation architecture data warehouses and Web based applications using SBVR, ORM, NIAM, Master Data Management, Metadata Repositories/Registries using SQL DBMSs incorporating Service Oriented Architectures Clients: Canadian Government departments Transport, Foreign Affairs, Defence, Superintendent of Financial Systems, Public Works including private sector, and CNIS (China National Institute for Standardization) 3

4 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 4

5 Background Many businesses suffer from weak IT infrastructure consisting of disconnected databases, applications and services Glaring eye-opener lack of documented business processes, data semantics New Technology, faster processing or shall we say faster hard line undocumented garbage processing is here! 5

6 Recap Conceptual Schema TR9007 Conceptual Schema essentially reflects static and dynamic behaviour rules of enterprise Processes address the dynamics part and Process Modelling has been around for many decades along with their own paradigms 6

7 The fallacy of process modelling techniques Various representational notations, description languages for focused domains (it is a free world.) Most process modelling paradigms focus on flow of control of operations, weaving a complex scenario that may include several re-usable individual standalone processes in the form of a service 7

8 How vs. What Note: Processes represent the How part of the behavioural dynamics Focus is lost on the What part and its semantics which is normally buried or hidden as a process Hey we need to orchestrate them together (see good old TR9007).. Change is more in the how and much less in what.e.g. airline ticket going from paper to e- ticket but person goes from point A to point B and associated semantics 8

9 Background Hype concepts or Buzzword contexts also bring in what is known as Services Services in a Services Oriented Architecture (SOA) has its own connotation Infrastructure Services Oriented Architecture (also known as Enterprise Service Oriented Architecture) Application Services Oriented Architecture..(this paper) 9

10 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 10

11 Objective of ISO Aim: Enable availability, common sourcing, and reuse of various kinds of process models includes workflows, business process, web services, software process described by different process modeling languages Objective: register administrative information of process models Structural information Semantic constraints within process models Flows between processes promote semantic interoperation between them 11

12 Overall structure of ISO Process_Modeling_Language -hasinput Input -constrainedby Precondition Goal 1..* 1 0..* 1 -modeltype * -referredto 1 -realizes 1..* Proces * Artifact 1 1..* Artifact_Constraint Condition 1 2..* -type : boolean(idl) * -referredto * -constrainedby 1..* 1 Composite_Proces -hasoutput Output -constrainedby Postcondition 1..* 1 0..* Atomic_Process 1 Control_Constraint Control_Construct -constrainedby * 12

13 Key concepts in ISO Atomic Process: a process model that cannot be decomposed Composite Process: a process consisting of at least two sub-processes, which can be atomic process or other composite process Process Model Language: name of the modeling language adopted by the registered process model Input: the message to be transformed or used by a process model Output: the generated message after transforming Control Constraint: to specify sequence control of a Composite Process Artifact Constraint: to restrict semantics of artifacts in Input/Output Precondition: refers to Input specifying the information state that may exist and should be satisfied before execution Postcondition: refers to Output representing desirable outcomes when a process is completed as specified. 13

14 ISO : Status Submitted in 2008 to ISO / IEC SC32 WG2 Metadata WG as a Working Draft Slated for progression into Committee Draft for 2009 Open for review and comments 14

15 ORM schema of ISO Goal Process Modelling Language.Owned by./... has... >=2... realizes.../... has... Process Composite Process... Model type.../... has has.../... Constrained by has.../... has output Has input.../... has... Control Constraint Input Artifact Output... has.../constrained by Referred to/... has... Pre Condition... has.../constrained by... has.../referred to Post Condition... has.../constrained by Artifact Constraint Condition... has.../..owned by... Atomic Process... has.../... Owned by... Control Construct 15

16 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 16

17 Positioning the Process Model in a model driven architecture SDLC There are SDLCs and SDLCs and SDLCs from waterfall, spiral, agile whatever! Here is an SDLC that has been successfully followed for NIAM / ORM based projects over the past 20 years and more (since CRIS 82..) ---[OK, new terminology has been added to keep up with the times ] Entails formalizing a semantic model (NIAM / ORM) as the kingpin core supplying semantics to other components and derivation of metadata Many parallels to OMG s Model Driven Architecture and SVBR driven 17

18 Positioning the Services and Processes in an overall ORM driven SDLC Propositions Business Process Model Business Requirements (Business activity model decomp.) X Process Model (n-1) F1, F2, F3, F4 semantics (IDEF0) Semantic Model i.e. Computation Independent Model (Natural Language Facts ORM, NIAM,CogNIAM ) F1 F2 Agent Atomic Process Store Actor F4 F3 (n level) CONTROL SEQUENCE MODEL Process Sequence Ordering Platform Independent Model (Grouped Facts) EVENT MODEL Events SERVICES MODEL Event Control Seq REPOSITORY Process REPORT DESIGN SCREEN DESIGN Web Services CREATE TABLE CHECK PRIMARY KEY FOREIGN KEY... CREATE TABLE VARCHAR CHECK PRIMARY KEY FOREIGN KEY UNIVERSE... Platform Independent Model (Attribute Model ER, UML..) Platform Independent Model (URI) Platform Specific Model [syn. vendor independent] (SQL) Vendor Platform Specific Model (Oracle 10g) Business Intelligence (Business Objects,Crystal Reports, Cognos...) 18

19 Business Activity Model Semantic Model Starting with a forest level view, analyzing the flows between the decomposed lowest level process (elementary or atomic) to derive a strong semantic model MOST PROCESS MODELLING APPROACHES PAY LIP-SERVICE TO THIS semantics STEP- --thus embedding their business rules in processes, sequences. 19

20 Propositions Business Requirements Agent Actor CONTROL SEQUENCE MODEL EVENT MODEL SERVICES MODEL F1 F4 REPOSITORY Atomic Process Process Seq (n-1) F2 F3 REPORT DESIGN Store F1, F2, F3, F4 semantics (IDEF0) (n level) SCREEN DESIGN Positioning the Services and Processes in an overall ORM driven SDLC CREATE TABLE CHECK PRIMARY KEY FOREIGN KEY... CREATE TABLE VARCHAR CHECK PRIMARY KEY FOREIGN KEY... X (Natural Language Facts ORM, NIAM,CogNIAM ) (Attribute Model ER, UML..) independent] (SQL) (Oracle 10g) Objects,Crystal Reports, Cognos...) Business Process Model (Business activity model decomp.) Process Model Semantic Model i.e. Computation Independent Model Propositions Business Process Model Process Sequence Ordering Events Platform Independent Model (Grouped Facts) Platform Independent Model Business Requirements (Business activity model decomp.) X Web Services Platform Independent Model (URI) Platform Specific Event Control... UNIVERSE... Model [syn. vendor Vendor Platform Specific Model Business Intelligence (Business Process Model (n-1) F1, F2, F3, F4 semantics (IDEF0) Semantic Model i.e. Computation Independent Model (Natural Language Facts ORM, NIAM,CogNIAM ) F1 F2 Agent Atomic Process Store Actor F4 F3 (n level) 20

21 Elementary, my dear Watson Note the separation of control sequence and event drivers from the atomic processes This is necessary, because when you address the viewpoint of a service Rigidly defined services with non-reusable processes break quickly Secret is to orchestrate atomic processes and stitch together the necessary couplings involving sequencing and events to form a Service 21

22 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 22

23 Positioning the Services and Processes in an overall ORM driven SDLC CREATE TABLE CHECK PRIMARY KEY FOREIGN KEY... CREATE TABLE VARCHAR CHECK PRIMARY KEY FOREIGN KEY... X Propositions Business Process Model Business Requirements (Business activity model decomp.) F1, F2, F3, F4 semantics (n-1) (IDEF0) Semantic Model i.e. Computation Independent Model (Natural Language Facts ORM, NIAM,CogNIAM ) Propositions Business Process Model Agent Actor Process Model F1 F2 Atomic Store Process F4 F3 (n level) Business Requirements (Business activity model decomp.) X CONTROL Process Sequence SEQUENCE MODEL Ordering Platform Independent Model (Grouped Facts) EVENT MODEL Events SERVICES MODEL Event Control Process Seq REPOSITORY REPORT DESIGN SCREEN DESIGN Web Services... UNIVERSE... Platform Independent Model (Attribute Model ER, UML..) Platform Independent Model (URI) Platform Specific Model [syn. vendor independent] (SQL) Vendor Platform Specific Model (Oracle 10g) Business Intelligence (Business Objects,Crystal Reports, Cognos...) (n-1) F1, F2, F3, F4 semantics (IDEF0) Semantic Model i.e. Computation Independent Model (Natural Language Facts ORM, NIAM,CogNIAM ) Process Model F1 F2 Agent Atomic Process Store Actor F4 F3 (n level) CONTROL SEQUENCE MODEL Process Sequence Ordering Platform Independent Model (Grouped Facts) EVENT MODEL Events Platform Independent Model (Attribute Model ER, UML..) 23

24 Applying to the selected IT infrastructure And now position the processes, control sequences, and event drives---incorporating the application infrastructure components into a service model i.e. de-couple complex processes (built in sequencing, and consisting of splittable composite processes) to stitch the service deliverable fabric 24

25 Propositions Business Requirements Agent Actor CONTROL SEQUENCE MODEL EVENT MODEL SERVICES MODEL F1 F4 Atomic Process Process Seq REPOSITORY (n-1) F2 F3 REPORT DESIGN Store F1, F2, F3, F4 semantics (IDEF0) (n level) SCREEN DESIGN Web Services CREATE TABLE CHECK PRIMARY KEY FOREIGN KEY... CREATE TABLE VARCHAR CHECK PRIMARY KEY FOREIGN KEY... Positioning the Services and Processes in an overall ORM driven SDLC X (Natural Language Facts ORM, NIAM,CogNIAM ) (Attribute Model ER, UML..) independent] (SQL) (Oracle 10g) Objects,Crystal Reports, Cognos...) Business Process Model (Business activity model decomp.) Semantic Model i.e. Computation Independent Model Process Model Process Sequence Ordering Events Platform Independent Model (Grouped Facts) CONTROL SEQUENCE MODEL Process Sequence Ordering Platform Independent Model (Grouped Facts) Platform Independent Model Platform Independent Model (URI) Platform Specific Event Control... UNIVERSE... Model [syn. vendor Vendor Platform Specific Model Business Intelligence (Business EVENT MODEL Events SERVICES MODEL Event Control Seq REPOSITORY Process REPORT DESIGN SCREEN DESIGN Web Services CREATE TABLE CHECK PRIMARY KEY FOREIGN KEY... CREATE TABLE VARCHAR CHECK PRIMARY KEY FOREIGN KEY UNIVERSE... Platform Independent Model (Attribute Model ER, UML..) Platform Independent Model (URI) Platform Specific Model [syn. vendor independent] (SQL) Vendor Platform Specific Model (Oracle 10g) Business Intelligence (Business Objects,Crystal Reports, Cognos...) 25

26 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 26

27 ORM Schema of Services Model. Extending the ISO metamodel to accommodate Services and Events Stitch together the processes for a service fabric Relate the service to events Accommodate the event with an event hierarchy The ORM Schema of Services Model 27

28 ORM Schema of the Service Model Service Event Event Step U... has.../... has has.../... has has.../... has... Has super/has sub Exception... has.../... has... Event Service... has.../... has... U... has.../... has... Process in Service... has.../... has... Atomic Process... has.../... has... Process Step 28

29 Common Services Metadata Model of Services metadata includes Functionality metadata (the business ) Technical metadata (the infrastructure ) Context metadata (the mappings ) Services Category Basic Services, Foundation Services, Management Services, Management Services, Security Services, Business Services, Identity Services. The ORM Schema of the Common Services Metadata 29

30 Services hierarchy. Services hierarchy to accommodate a Service Decomposition Some ask..is Service a Process?... Wo, Wo, Wo! There are differences a process is performed in order to achieve a service deliverable, while a service is in itself deliverable component a service is a commitment of the business to achieving an outcome A process is a mechanism to deliver or achieve that outcome 30

31 ORM Schema of the Common Services Metadata Functionality metadata Service... has.../... has... Technical metadata Service Metadata Context metadata esses.../... has... Service Category Servic Provid 31

32 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 32

33 SOA Overlay based on Atomic Processes Or How to avoid a spaghetti Services Oriented Architecture resulting from an ad hoc assembly of interwoven applications? Business Process Modelling is top down SOA is a bottom up procedure Service requires the execution of one or more reusable atomic processes as per the Event and Control Sequence models Hey you have something that works and is solid!!! 33

34 Overlay Positioning Services and Processes (n-1) (n-1) (n-1) SERVICES DRIVING PROCESSES SERVICES HIERARCHY BUSINESS PROCESSES Process Atomic process (n-1) Service 34

35 Outline Background Introduction of ISO Positioning the Process Model in SDLC Processes in SOA ORM Schema of the Service Model SOA Overlay based on Atomic Process Summary 35

36 Summary Generally, processes and services lose emphasis on data and semantics Process sequencing buried in complex thread--- not flexible, not reusable, resulting in redundancies and anomalies These complex operations are essentially reusable elementary atomic processes ISO is extended with an ORM defined Service Model and Common Services Metadata model 36

37 Summary Secret is to unravel the complex thread and insulate a service by separating Control and sequencing Event driven services Strong NIAM / ORM driven data schema containing business rules that were formerly interwoven Don t knock it.it works and works damn well!!! 37

38 Acknowledgement Productive Discussions with: Dr. Robert Meersman Dr. Sjir Nijssen Paul Thompson Dr. Yangfan He Dr. Jian Wang Grants: National Basic Research Program of China (973), National High Technology Research and Development Program of China (863), National Natural Foundation of China, and Provincial Natural Science Foundation of Hubei Province, China. 38