Activities in BPEL

Activities are most useful for BPEL Process all activities are drag and drop to BPEL Service Component BPEL process consist of BPEL Assign activity, BPEL Invoke Activity, BPEL Receive activity, BPEL Assign activity , BPEL Switch Activity, BPEL While Activity, BPEL Transform Actvity


BPEL Assign Activity used for to control the data, copy the content one variable to another.


BPEL Transform Activity which is also one type of assign activity which is uses the XSLT to map the elements source format to target format which performances more faster than assign activity. XSLT (Xexntesible Stylesheet Language Transformation) which transform the data one element to another element of other documents. 


How to control the process by using switch, while, flow, Flown activities, "Switch Activity" used for implementing conditional branches, "While activity" used for implementing loops, "Flow activity" is used for implementing branches in Parallel, "FlowN activity" is used for run time Parallel branches decides on server side it means dynamic parallel branches.


"BPEL Invoke activity" used for invoke the services, which identify the partner link and specify the operation


"BPEL Receive activity" is used for asynchronous callback response from partner link of service.


BPEL Scope Activity used for manipulating the faults, events, compensation and correlation sets. Scope Activity used for simplifies BPEL process flow. 


BPEL Wait Activity used for pause the process for a period of time.


BPEL Empty Activity does not do anything but syntax is required for feature of BPEL Process but which is not perform any activity.

What is BPEL Process in SOA

"What is BPEL Process in SOA?", (Business Process Execution Language) BPEL Process is a language used for the composition, orchestration and coordination of webservics.  In this post we will explain BPEL, define the BPEL role with regard to Service Oriented Architecture and explain the process-oriented approach to SOA and the role of BPEL. 


In BPEL the Enterprise application and information systems have become more more fundamental assets to companies. The Companies are trust on them to be able to perform business operations. 

What is SOA Principles

In this post you will get any idea of what is SOA principles, SOA Principle defines the framework in which consumers and services will collaborate and acts as general guidance for the design and development of services. There are number of principles that can be applied to an SOA. 

• Loose Coupling 
• Interoperability 
• Reusability 
• Discoverability 
• Governance 

Loose Coupling 
"What is SOA" "Why need SOA" you just raise question raise your self? the answer is Loose Coupling. Loose coupling principle, consumers and services do not communicate directly consumers and services communicate via messaging. Using a message to exchange request and replies avoids any direct technical connections between consumers and services. In addition to messaging, there are other service interface design techniques that can be applied to further limit the degree of coupling between consumers and the service.


Messages exchanged between consumers and services are realizations of the service interface. In the case of a Web service the service interface is defined by the combination of Web service Definition Language artifact and xml schem definition as its referenced metadata. These two types of interface artifacts are the foundation of any web services. The design and development of these two interface artifacts are a focus of the loose coupling principle. 

In SOA, a service may invoke a set of database activities as part of its behavior. However this is not a limitation. Through the service operations, a service could also provide computational, presentation, transformation, and other types of behavior. Regardless of the functionality provided by the service, the loose coupling principle must be applied. 


Interoperability 


Interoperability is one more type of "what is SOA" principle that eliminates technology specificity and constraints that may prohibit, restrict, or constrain the ability to collaborate in the soa. 
Interoprability allows consumers and services that are developed and platformed on different technologies to exchange information and collaborate. That is service might be developed using java, platformed on a server using the Linux operating system, and accessing an Oracle database. Consumers of this service might be developed using Visual C++ or even COBOL. They might run on Windows platforms or mainframe MVS platforms. The variations and possibilities are almost endless. A core tenet of SOA is to allow these consumers and services to collaborate, regardless of the technology on which they are based. 


Reusability 
The principle of "What is SOA" is reusability  to design and develop with an emphasis on cost avoidance. A service that is designed and developed to support the loose coupling and the interoperability principles is likely a good candidate for reuse. That is , original consumers as well as new consumers can exploit the functionality of the service. As new consumers express their requirements and where those requirements can be met by the functionality of the existing service, they can avoid having to design and develop yet another new service.

Discoverability 

Finding a service is the first step to service reuse and consumption. Even though a service might provide extensive functionality, it is largely ineffective if the service cannot be discovered for later use.

It contains published information about a service. A typical commercial service registry technology also includes some form of search or find capability. This allow designers and developers to search for already developed services as candidates for reuse.

Governance 

A successful SOA  and services implementation will incorporate services and services artifacts that comply with the loosely coupled, interopreable, reusable discoverable principles. SOA governance will provide the rules and framework from which compliance to these principles can be measured and identify opportunities for appropriate remediation of noncompliance. Some SOA practitioners might argue that governance is a process or a practice, rather than a principle, contend that to implement an effective SOA, governance is more fundamental and crosses the lifecycle of SOA. 

What is Service Oriented Architecture (SOA) definition

In this post I will explain what is SOA, why SOA is required for next IT generation ,these are the questions comes to you when you learn SOA.

A service-oriented architecture (SOA) is a combination of consumers and services that collaborate, is supported by a managed set of capabilities is guided by principles, and is governed by supporting standards. 


Consumers and services are all participants and collaborators in an SOA. Which is they interact with one another to request services and resolve these requests. The context for these interaction is determined by the service interface and is typically expressed as a message that moves between the collaborators.


In Service-oriented architecture consumer is technology that in some manner interacts with, consumes, and exploits services. Typically and within the definition of an SOA, a consumer is an application or piece of software that will interact with another application or piece of software as a service or possibly as an intermediary. While SOA consumers are generally software, this is changing, and we'll begin to see more appliance and hardware SOA consumers. 

SOA Consumer and Service 

From an SOA perspective the service is generally some set of application functionality. The provider of the service may be a combination of the service behavior and the location at which it is identified and invoked. Again using the office supply analogy, the service being offered is that of returning the available inventory for an item. In this regard, the office supply store is know as the service provider. The interaction between the consumer and the service is enabled by a request for the available inventory position of an item and the inventory count returned in the reply. 

In Service-Oriented Architecture interesting extension of the consumer and service definition is that of an intermediary. As implied by the name, an intermediary is positioned somewhere between a consumer and a service. Note that this is logical positioning, and the physical or network locations of the consumers, services and intermediaries can vary. An intermediary may provide some form of service behavior, or it may just mediate between other consumer and services. If we carried our office supply analogy further, an example of an intermediary might be a discount retailer. The customer interacts directly with the discount retailer, and the retailer then works with the office supply company on behalf of the consumer. 


In service oriented architecture a consumer interacts with an intermediary rather than directly with the service. Depending upon the perspective and direction of the interaction, an intermediary can hold similar roles of both a consumer and a service when following the interaction from the consumer to the intermediary, the intermediary can be thought of as the target of the interaction or even as logical extension of the service. When following the interaction from the intermediary to the service, the intermediary can be thought of as an originator of the request or logically as a consumer of the service. 


This front end such as mediation service, wrapper service might be another separate application that does nothing but mediate the interaction between consumers and the existing application. In this mediation service acts as an intermediary between service consumers and the legacy application.


 One every important point to remember is that with any interaction the service interface  is a critical component. It describes the rules by which the SOA participants and collaborators interact, and it also defines the context of that interaction as one or more messages. 

Oracle SOA File Adapter Services

File Adapter Service Use cases 

ORACLE BPEL Interview Questions

1. What are the Major Elements in WSDL?
2. Explain about SOAP Structure?
3. Can you describe about SOA Governance? 
4. What are the BPEL activities? 
5. Difference between pick activity and receive activity? 
6. Difference between Complex Type and Simple Type? 
7. Difference between while activity and pick activity?
8. What is the use of pick activity? 
9. What is the use of correlation?
10. Difference between synchronous and Asynchronous process?
11. What is end point URI?
12. What is dehydration storage tables?
13. What is automated roll-back?
14. In Oracle SOA 11g What is difference between imports & Include?
15. What is choeeography?
16. How to make partner link Dynamically?
17. What is synchronous file read ?
18. Can I import two xsd files which are having same elements and same file name?
19. What is transient and durable BPEL?
20. In database adapter configuration difference between XA data source and non-XA data source?
21. can explain Plan.xml ?

Oracle SOA Interview Questions and Answers

1. Explain About Web service?


Web service is type of software system which is used for exchange the data and use information from one machine to another machine through network. Generally Web services based on the standards such as TCP/IP, HTTP, Java, HTML and XML.

Web services are pure xml based which is used for exchange information through Internet to direct application to application interaction. These systems include programs, objects, messages or documents.