Prasanna B

Из переписки.

Can anybody tell me when we can go for SOA?.What exactly SOA mean?.

Please help me in this regard.

With Regards

1. Hi there is not hard and fast rule for service oriented architecture. I will give you a scenario where service would result better. In classical programming a common business model can be packed in a dll file and can be reused with multiple applications. So when a critical change in the dll then you have to apply this in all the applications which use the dll. This is hard to maintain. Where as a webservice abstract the access with a contract. Under the hood it change the business logic but the client doesn't need to worry about it. For example you are getting a customer details from a webservice, the service get the details from a mysql database. Later the management decide to change the database to sqlserver. But the client do not worry about it. Same way the implementation of any business logic is loosely coupled from the client and client only depends on a contract not on a concrete implementation. Even a webservice communicate other webservices and client doesn't aware of all these. The Grid computing in clould applications is a form of SOA as well.

Most of the webservices offers a common protocol and the information exchange in a common format like xml. So a webservice created in c# can be communicated by a php application.

The downside of webservices are sometimes the webservices are over abstracted where you won't get the information in flexible way (less information or get unnecessary information along with what you needed). Another thing is performance hit.

This is a simple answer for your question. Read a good book on SOA and internet also has many articles on this topic. Good luck

1. SOA just means an application involving services really. Many would go further and say that all the application logic must be encapsulated or at least available via services.
2. It's pretty academic since for a practical application, who cares what label some people may or may not stick on it?
3. Putting all your logic into services is somewhat cumbersome for many apps and of course you have to be connected. So there's an argument that you might as well have that logic in web pages or whatever instead of the services.
4. Why do you ask?

Not exactly distributed applications, isn't it?. Distributed applications still have a kind of dependency with data structures like.net remoting, RMI all use stub and skeleton model. Where as web services is totally unaware of the client by general means. When a service has to know what data the client uses then the service has to be modified for each clients. That is not the whole idea. When you sign up for an email service you can access to the service where you agree for a terms and conditions. Same way the web services are accessed through a contract. The service doesn't know how the clients consume it. Only the client knows how to use the service. But using SOA you can distribute the layers to different servers. That is possible.

Your question "So if I write a aplllication,Will I able to access a service that is needed to my appliction using SOA?.". The answer is yes. Here are some links you can start with

http://www.codeproject.com/KB/webservices/myservice.aspx

http://support.microsoft.com/kb/308359

The book

Дата добавления: 2014-01-07