Web Service Vs JINI

[Tridib Bolar]

Hi,

I have two queries regarding XML based Web Service and JINI.
1) What are the differences between XML based Web Service and JINI?
2) Does XML based Web Service is better to JINI?


Thanks & Regards
Tridib

[William Brogden]

You appear to be trying to compare two entirely different technologies - is this some weird homework assignment??

Try www.jini.org to get started understanding JINI, there are web service tutorials all over the place.

Bill

[Yohan Liyanage]

Bill is correct. The objectives of Web Services and Jini are completely different. Jini Technology is a Java-based network technology which is built on JavaSpaces (or Tuple Space) concept.

On the other hand, an XML Web Service is a web based application which can be consumed by other web applications. XML Web Services are not limited to Java Platform. Of course Java provides mechanisms to build Web Services (and its really simple with JWS), but many other languages such as .NET, PHP, .. can be used to build a web service. Web Services use XML as their medium of data transmission.

One similarity of these two is that both belong to "Distributed Computing". Both technologies provide means to distribute the work among computers, in their own way.

[Tridib Bolar]

Originally posted by Yohan Liyanage:
Bill is correct. The objectives of Web Services and Jini are completely different. Jini Technology is a Java-based network technology which is built on JavaSpaces (or Tuple Space) concept.

On the other hand, an XML Web Service is a web based application which can be consumed by other web applications. XML Web Services are not limited to Java Platform. Of course Java provides mechanisms to build Web Services (and its really simple with JWS), but many other languages such as .NET, PHP, .. can be used to build a web service. Web Services use XML as their medium of data transmission.

One similarity of these two is that both belong to "Distributed Computing". Both technologies provide means to distribute the work among computers, in their own way.

Yes it�s absolutely true, but my concern is, Service Oriented Architecture (SOA) is already implemented using XML based Web Service, here I am trying to implement it using JINI technology, I want to know what are the pros and cons for the same?

[William Brogden]

here I am trying to implement it using JINI technology,

Ah! That is a bit clearer. No matter how fancy the acronym - SOA - SOAP - REST - etc etc. - the basic technology is passing messages around between applications in a loosely coupled network. There is no reason that JINI applications can't exchange XML formatted messages - its just text, nothing magic.

With "web services" the message protocol is based on HTTP - a very widely supported protocol with well understood conventions and support in practically every computer language in common use. One would use HTTP where the service users are widely distributed and must use the Internet for connectivity.

JINI networks build their own connections using JINI socket and networking conventions - typically in Java although there may be other implementations I am not familiar with.

Jini is NOT built on JavaSpaces, it is the other way around, Jini is not restricted to Javaspaces. In my opinion, there is a place in "web services" for Javaspace technology in terms of distributed computing where there is a big computational load.
This is my survey article on the subject.

Are the clients for this service using the Internet to connect or are they all on a local network?

Bill

[Tridib Bolar]

Thanks Bill,

The answer of your last query is; the clients are the internet client. They will communicate through Internet and will discover the service from the service locator using multicast or unicast approach.

Because the client is the Internet client the operational platform/language may be other than Java. My actual concern is, if I use JINI to implement SOA could I implement the language independency? As per my knowledge JINI client needs the proxy to connect with server which nothing but a Java interface, so how two totally different applications with different platform/language (e.g. Java server/.NET client or COBOL server/CPP client) can interact with each other using JINI?

[William Brogden]

You seem intent on using JINI but I think it would be hard to justify, especially since your clients reach the system over the Internet.

Lets back off for the 10 thousand foot view (as we used to say in the consultant biz) to determine the requirements without any specific technology in mind.

1. Do clients interact only with the central server or do they have to locate each other and "talk" independently?

2. Do clients require immediate responses or can they submit requests and come back later for the results?

3. The chunks of data that are being moved around - how large are they?

4. Do you have a requirement to implement a particular SOA pattern or is the design still at a preliminary stage?

5. How much control do you have over the software (including operating system) on the client side? - on the server side?

6. Is there some reason you are not considering the UDDI - WSDL approach to service discovery?

many more questions occur but lets start with those.

Bill

[Tridib Bolar]

I am trying to answer your queries one by one.
1st of all I really want to implement SOA using JINI, but it is not for any commercial use, it is for the R&D purpose. During this implementatio0n phase I want to get the detail knowledge on pros and cons of JINI for SOA.

1. Do clients interact only with the central server or do they have to locate each other and "talk" independently?

Ans: They must talk independently with each other using the common Service Locator. I mean to say client/consumer should not connect with provider directly, they must get the provider details from service locator but one consumer should be able to communicate with multiple providers and vice versa.

2. Do clients require immediate responses or can they submit requests and come back later for the results?

Ans: Most of the time clients require immediate responses. To me it is actually depends on business requirement, it is better if we could implement both synchronous and asynchronous way of responding.

3. The chunks of data that are being moved around - how large are they?

Ans: It is near about 25-30 KB

4. Do you have a requirement to implement a particular SOA pattern or is the design still at a preliminary stage?

Ans: Yes, as I say I want to implement the SOA pattern using JINI . There is no predefined design, it is from scratch.

5. How much control do you have over the software (including operating system) on the client side? - on the server side?

Ans: I don�t have any control on the other (consumer/provider) side but mostly it will be mainframe system

6. Is there some reason you are not considering the UDDI - WSDL approach to service discovery?

Ans: I am trying to get some way out.

[William Brogden]

1. Do clients interact only with the central server or do they have to locate each other and "talk" independently?

Ans: They must talk independently with each other using the common Service Locator. I mean to say client/consumer should not connect with provider directly, they must get the provider details from service locator but one consumer should be able to communicate with multiple providers and vice versa.

That takes us out of the realm of "web service" for sure, and it takes me out of my depth - a google search for "jini over internet" found some interesting citations including this dissertation - PDF format.

Bill

[Tridib Bolar]

Thank you Bill for your cooperation. I think your document will help me lot.