1. 95-843: Service Oriented Architecture 1 Master of Information System Management Service Oriented Architecture Lecture 10: Service Component Architecture (SCA) Sources: www.osoa.org “SOA for the Business Developer” by Margolis “Introducing SCA” by Chappell

2. 95-843: Service Oriented Architecture 2 Master of Information System Management Composite Services Architecture (CSA) In March 2007, Composite Services Architecture (CSA) is passed on to OASIS by the Open Service Oriented Architecture collaboration (www.OSOA.org). CSA is supported by BEA, IBM, Oracle, Tibco, Red Hat and others. CSA Consists of SCA (Service Component Architecture) and SDO (Service Data Objects). Implemented by IBM WebSphere, Oracle, Red Hat, Tibco, and the open source Apache Tuscany. Describes how to compose and deploy applications supporting SOA. Decouple business logic from details associated with the call on that logic. Introduces The Service Component Definition Language (“skiddle”) to describe composites.

3. 95-843: Service Oriented Architecture 3 Master of Information System Management SCA Specifications (1) Assembly model defining composites, components, references and wires Policy Framework allowing analysts to define constraints, capabilities and qualities of service expectations Bindings allowing heterogeneous transports (SOAP, JMS, IIOP,etc.) Java annotations, API’s and component implementation (@Remotable) C++, BPEL, PHP, EJB and Spring for SCA

4. 95-843: Service Oriented Architecture 4 Master of Information System Management SCA Specifications (2) The Assembly model defines composites, components, references and wires. The assembly model defines how components are combined into composites and are packaged and deployed as services. We specify such details as encryption, authentication and queuing outside of the business service.

5. 95-843: Service Oriented Architecture 5 Master of Information System Management 5 SCA Specifications (3) The Policy Framework allows analysts to define constraints, capabilities and qualities of service expectations. WSDL does not support the description of policies. The SCA Policy Framework uses WS-Policy and WS-PolicyFramework to describe policies for service users. From www.osoa.org:www.osoa.org Business value: The ability to define policies outside the services themselves lets administrators set and change the policies without changing code. It also means administrators know their policies are implemented globally.

6. 95-843: Service Oriented Architecture 6 Master of Information System Management 6 SCA Specifications (4) Bindings allow heterogeneous transports (SOAP, JMS, IIOP,etc.) to be used. Bindings specify the mechanisms to access particular kinds of components. Applications built with SCA can use Web services, JMS, JCA and EJBs. (More bindings are on the way from osoa.org.) As you would expect, the bindings can be defined outside the code itself. Business value: The bindings provided in SCA allow developers to use a wide variety of services without knowing the details of how those services are accessed. With the bindings external to the code, the bindings can be changed without changing the code. From www.osoa.org:

7. 95-843: Service Oriented Architecture 7 Master of Information System Management SCA Components (1) Implemented in BPEL, Java, C++, etc. This may also be a composite. services properties references … …

8. 95-843: Service Oriented Architecture 8 Master of Information System Management SCA Components (2) Implemented in BPEL, Java, C++, etc. This may also be a composite. services properties references has a name and list of policy intents has a name and an implementation type has an interface and a binding names and values to be passed in includes a binding

9. 95-843: Service Oriented Architecture 9 Master of Information System Management SCA Components (3) Business logic Implementation services references Property values passed in at runtime. Operations available to clients. Other services this client depends on. Dependency injection: The SCA runtime performs a lookup for the reference. The business logic need not be concerned with how the other service is accessed. Nor is the business logic developer concerned with how this component is accessed. That detail is specified as a binding - outside of the business logic.

10. 95-843: Service Oriented Architecture 10 Master of Information System Management SCA Components (4) : A component is the atom of an SCA application. It lives within a composite. A component is a configured implementation. SCA is language agnostic. SCDL defines how the component interacts with the outside world. A component might talk to other components within its own domain or outside of its own domain. An SCA runtime knows what to do with this.

11. 95-843: Service Oriented Architecture 11 Master of Information System Management SCA Components Quiz (1) http://www.myserve.com/service 0 http://www.etc.com/service Quiz: What can we say about the component being defined?

12. 95-843: Service Oriented Architecture 12 Master of Information System Management SCA Components Quiz (2) http://www.myserve.com/service 0 http://www.etc.com/service And this one? Other bindings include binding.jms and binding.ejb.

13. 95-843: Service Oriented Architecture 13 Master of Information System Management SCA Composites (1) services properties references wire

14. 95-843: Service Oriented Architecture 14 Master of Information System Management SCA Composites (2) services properties references wire Components

15. 95-843: Service Oriented Architecture 15 Master of Information System Management SCA Composites (3) services properties references wire Perhaps implemented in BPEL. Perhaps implemented in Java.

16. 95-843: Service Oriented Architecture 16 Master of Information System Management SCA Composites (4) services properties references wire How this communication is done may be left up to the SCA runtime. These may run on different machines.

17. 95-843: Service Oriented Architecture 17 Master of Information System Management SCA Composites (5) services properties references wire reference service A wire is an abstract representation of the relationship between a reference and some service that meets the needs of that reference.

18. 95-843: Service Oriented Architecture 18 Master of Information System Management SCA Composites in “Skiddle” : A service contains binding information. A reference contains binding information. A wire connects components. Components may live in different processes or on different machines. A composite solves a business problem. Components might be written in Java, BPEL or some other language. A composite may be used as a component in a higher-level assembly. A composite does not cross domain boundaries.

19. 95-843: Service Oriented Architecture 19 Master of Information System Management SCA Domains Contain one or more composites. May cross machine and process boundaries. Are each managed by a single group of people. Run on a single vendor’s SCA runtime. Place no restrictions on how internal communication is done.

20. 95-843: Service Oriented Architecture 20 Master of Information System Management SCA Bindings Bindings specify how one component communicates with another. A single component may have multiple bindings. The use of bindings separate what a component does from how we communicate with it.

21. 95-843: Service Oriented Architecture 21 Master of Information System Management SCA Services, References & Properties Components expose one or more services. How the services are described depends on the technology. Descriptions for clients in other domains would typically use interoperable WSDL. A service provides some number of operations. If a component uses other services then these are described with references. Properties are values taken from the SCDL and describe the world to the component.

22. 95-843: Service Oriented Architecture SCA Summary From www.osoa.org:www.osoa.org As your SOA becomes more complex, you'll need the simplicity and flexibility of SCA. The Service Component Architecture helps you: Save time and money - A simpler API means a shorter learning curve with fewer errors. Enable and encourage reuse - Developers can create composites that perform useful functions. SCA makes it easy to use and reuse them. Manage your system - Because policies can be defined outside the code that performs the service, you can change the policies without changing the code. 22 Master of Information System Management

23. 95-843: Service Oriented Architecture 23 Master of Information System Management Service Data Objects (SDO) A specification to unify data programming across heterogeneous data sources. May be used by SCA to interact with data sources. Several competing approaches exist in the Java persistence API space. SDO is more mature and general than Java’s Persistence API (JPA). SDO is not Java specific, e.g., has support in PHP.

24. 95-843: Service Oriented Architecture 24 Master of Information System Management Service Data Objects (SDO) Typical data sources include: JDBC Entity EJB’s Web Services XML sources JMS messages Enterprise Information Systems through J2EE Connector Architecture

25. 95-843: Service Oriented Architecture 25 Master of Information System Management Goals of SDO To simplify the life of the application developer. To provide new opportunities for tools and frameworks to work with a wide variety of data sources. Thus, we see support for both static (account.getBalance()) and dynamic (resultSet.getFloat(“BALANCE”)) data API’s. Quiz: Which one is for application programmers and which one is for tools?

26. 95-843: Service Oriented Architecture 26 Master of Information System Management SDO Architecture (1) Based on disconnected data graphs and optimistic concurrency (OC). client Data Access Service (DAS) Data Source OC: If any change occurs on the backend while the client is making changes, a subsequent attempt to update must be rejected. The client would then need to take appropriate action. Pessimistic concurrency locks resources. OC is preferred if concurrent access is rare. One DAS may work with RDBMS and another may work with XML etc. The DAS creates the graph of data objects.

27. 95-843: Service Oriented Architecture 27 Master of Information System Management SDO Architecture(2) Data Objects hold the data and metadata. Data Objects have rich relationship support. The Data Graph logs every change to the data. client Data Access Service (DAS) Data Source Xpath is used to dynamically select data objects from the data graph.

28. 95-843: Service Oriented Architecture 28 Master of Information System Management SDO Architecture(3) Data Access Services come in various forms: client Relational Data Access Service EJB Data Access Service XML Data Access Service

29. 95-843: Service Oriented Architecture SCA and JBI See article by Mike Edwards (IBM) at http://www.osoa.org/display/Main/Relationship+of+SCA+and+JBI How does SCA differ from JBI? JBI stands for Java Business Integration JBI defines a set of of Service Provider Interfaces for middleware providers to implement if they want to install new service engines (SCA implementation types) or binding components (SCA bindings). SCA is for developers, assemblers and deployers of business services. SCA says nothing about how new implementation types or new bindings might be introduced. JBI is for middleware vendors. SCA is for business developers. 29 Master of Information System Management

30. 95-843: Service Oriented Architecture SCA and JBI Bottom Line See article by Mike Edwards (IBM) at http://www.osoa.org/display/Main/Relationship+of+SCA+and+JBI http://www.osoa.org/display/Main/Relationship+of+SCA+and+JBI “JBI should be considered a Java technology that potentially helps middleware vendors to implement SCA. JBI and SCA do not compete or conflict with each other.” “SCA, on the other hand, allows multiple technologies to be used to implement services( e.g. Java, BPEL, C++) and multiple bindings to communicate with services (e.g. web services, JMS).” 30 Master of Information System Management