new to web services

[Grishma Dube]

Hi All,
I'm very much new to web services. Can anyone explain me the concept of web services in simple terms? what exactly a web service means and what are the benefits of it??
TIA
Grishma

[Balaji Loganathan]

Defn from W3C:
The World Wide Web is more and more used for application to application communication. The programmatic interfaces made available are referred to as Web services
Read this tiny but useful link
and this link will help you to understand the benefits of web services
[ April 13, 2004: Message edited by: Balaji Loganathan ]

[Grishma Dube]

suppose i've 3 different applications, 1st is written in Lotus Notes, another is a J2EE application and 3rd one is a mainframe application.
can i create a web service so that my lotus notes application can use j2ee application's business logic or mainframe application ? Do we have to develop the WS in server-side programming language?
Can we develop a WS for standalone application?

and if yes, how to do it??
TIA
Grishma
[ April 15, 2004: Message edited by: Grishma Dube ]

[Lasse Koskela]

can i create a web service so that my lotus notes application can use j2ee application's business logic or mainframe application?

In theory, yes, as long as the programming language you're using has the ability to do HTTP requests and parse XML documents.

Do we have to develop the WS in server-side programming language?

What do you mean by a server-side programming language? In any case the code will run server-side so I guess the answer is yes...

Can we develop a WS for standalone application?

I'm not sure what you mean by this, but the answer is probably yes.
[ April 15, 2004: Message edited by: Lasse Koskela ]

[Grishma Dube]

suppose my requirement is:-
i require an interface in java for login...after authentication, the user should be able to access all application which are developed in various languages and deployed on different platforms say lotus notes, mainframes, java/j2ee, etc.
can i achieve this using web services or is there any alternative???
TIA
grishma
[ April 16, 2004: Message edited by: Grishma Dube ]

[Lasse Koskela]

Originally posted by Grishma Dube:
i require an interface in java for login...after authentication, the user should be able to access all application which are developed in various languages and deployed on different platforms say lotus notes, mainframes, java/j2ee, etc.
can i achieve this using web services or is there any alternative???

From the Java client's point of view, yes, using web services would make sense -- it's a pretty universally interoperable protocol stack. However, I don't know what kind of product offerings there are for implementing the actual services (the server-side stuff) in Lotus Notes, for example. It could be that you need to deploy a web service separate from Lotus Notes which then proxies whatever requests it receives to "native" calls to Lotus Notes. For mainframes, there are some web services engines available but again I'm not sure for which vendors' mainframes (IBM mainframes should be among the best supported, I guess). Exposing web services from J2EE and .NET are a walk in a park, of course.

[Grishma Dube]

Thanx a lot.
Now i've a clear picture of what i'm supposed to do..
I've one j2ee application which contains one module called reverse auction. I want to reuse this module. For this purpose i want to create a web service for the reverse auction. This application is deployed on Oracle 9ias rel 2.
i dont know from where to start. can anyone guide me???
[ April 19, 2004: Message edited by: Grishma Dube ]

[Balaji Loganathan]

Originally posted by Grishma Dube:
I've one j2ee application which contains one module called reverse auction. I want to reuse this module. For this purpose i want to create a web service for the reverse auction. This application is deployed on Oracle 9ias rel 2.
i dont know from where to start. can anyone guide me???

One idea could be to create a proxy method to access the EJB component reverse auction and expose that class as a service.
Something like( rough code)

public class AuctionService
 {
  public String getAuctionReverse(String someinput)
  {
   //Initialize JNDI context
   //Call EJB home with the context
   //Initialize the ejb instance
   //Call the reverse acutoion method
   //clear EJB
   //return processed output
  }
}

Now you can expose the class AcutionService as a webservice which can be accessed by other clients.
Make sense ??

[Lasse Koskela]

Adding to Balaji's suggestion, you also don't have to implement everything at once -- you can, for example, implement "public String getAuctionReverse(String someinput)" to return a fixed string every time, develop your side of the system with this stub, and later on integrate the two systems by implementing the getAuctionReverse() method to actually contact the remote service.