aspose file tools*
The moose likes Web Services and the fly likes Basic requirements of WS Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of Java 8 in Action this week in the Java 8 forum!
JavaRanch » Java Forums » Java » Web Services
Bookmark "Basic requirements of WS" Watch "Basic requirements of WS" New topic
Author

Basic requirements of WS

L Goundalkar
Ranch Hand

Joined: Jul 05, 2001
Posts: 395
Hi All,
Can anyone tell me what are the basic requirements of creating or developing a simple web service.
How a web service is different from RMI, CORBA and so on.
Being a Java developer what are the new technologies I have to learn to start a new ride in Web services.

TIA

------------------
L Goundalkar
lggoundalkar@hotmail.com
Sun Certified Programmer for Java 2 Platform


<b>L G Goundalkar</b><br /> <a href="mailto:lggoundalkar@yahoo.com" rel="nofollow">lggoundalkar@yahoo.com</a> <br />Sun Certified Programmer for Java 2 Platform.<br />Sun Certified Web Component Developer for J2EE.
Stanley Tan
Ranch Hand

Joined: May 17, 2001
Posts: 243
I mostly do Web Services in .NET. How can I do it with Java?
sridhar satuloori
Ranch Hand

Joined: Nov 05, 2001
Posts: 144
http://64.27.69.233/JACE30_WebServices.html has the good description about webservices and some useful links
Sridhar

L Goundalkar
Ranch Hand

Joined: Jul 05, 2001
Posts: 395
Hi Sridhar,
There is something wrong with the URL you have given.
Thanks.

------------------
L Goundalkar
lggoundalkar@hotmail.com
Sun Certified Programmer for Java 2 Platform
Kyle Brown
author
Ranch Hand

Joined: Aug 10, 2001
Posts: 3879
Hi folks.
Basically, web services are similar to other distributed technologies like CORBA and RMI, but with a significant distinction.
Web Services consists of SOAP (the protocol for distribution), WSDL (the IDL for describing types and end points) and UDDI (the binding service, which is how you locate WSDL-implementing endpoints).
While CORBA has an underlying IIOP protocol that is limited to flowing particular low-level C datastructures over TCP/IP sockets, the SOAP protocol that underlies Web Services simply flows XML (plain text) and can do so over not only HTTP, but SMTP, JMS, and other protocols as well. As such, it makes it possible to use SOAP in ways that you can't use RMI or CORBA.
Some good links to start learning SOAP programming can be found in this other thread:
http://www.javaranch.com/ubb/Forum51/HTML/000001.html
Kyle
------------------
Kyle Brown,
Author of Enterprise Java (tm) Programming with IBM Websphere
See my homepage at http://members.aol.com/kgb1001001 for other WebSphere information.


Kyle Brown, Author of Persistence in the Enterprise and Enterprise Java Programming with IBM Websphere, 2nd Edition
See my homepage at http://www.kyle-brown.com/ for other WebSphere information.
Stephen Graham
Greenhorn

Joined: Oct 02, 2001
Posts: 11
Mr. Goundalkar:
Your three questions deserve (at least 3) answers:
1) Basic requirements of creating/developing a simple web service:
- This depends on your starting point. Many organizations already have their business processes in some automated form. The use of Web services in this case is to expose one or more operations from these business processes in a form invocable over the Internet. Currently, use of SOAP is quite popular as the mechanism to send messages over HTTP. We will see moving forward that in many cases (particularly document centric messaging) that simple post of an XML payload using HTTP will be sufficient. SOAP has benefits in an RPC-centric model, but it is not clear that this will be the prodminant model within the next 12-18 months.
If you are building the business logic from the ground up, you will need to choose an implementation technology (I recommend J2EE)and then expose the EJB as a Web service.
net/net: to get started, you need a the business logic implemented in some programming language, and you need some sort of SOAP middleware (I recommend Apache Software Foundation's Axis project).
Once you get your feet wet with this, you can then move up the stack (make the Web service secure, describe it using WSDL, publish it in a UDDI registry). Walk first, then run. Happily there is plenty of tooling available to help out.
2) How is a Web service different from RMI, CORBA, etc.
Web services have in common with RMI and CORBA the fact that they are all distributed computing technologies. Web service differs in a couple of very important points.
a) intent: Web services is the first distributed computing technology to marry RPC-centric and messaging (document centric) models. RMI and CORBA are unapologetically RPC. Prediction: the business world will move to document-centric model within 12-18 months.
b) granularity: this is somewhat associated with (a). Web services, when done right, encourages much more coarse grained, less brittle APIs than RMI and/or CORBA.
c) Web services is NOT distributed objects. You will not see notions of distributed garbage collection, etc. with Web services. This is incredibly simplifying, and forces developers to abandon the false-promise of local/remote transparency.
d) XML. Don't underestimate the power of XML. It is readable, simple, flexible and is the underlying power source for the Web services approach.
3) What are the new technologies?
Happily, your Java skills will still be very important. Web services is an access technology, not an implementation technology. The logic still needs to exist in program form. Keep using Java, it is a good language for implementing logic in a portable, object-oriented fashion.
The tooling support makes it possible to do Web services without learning any new technologies (just use the tools and you are done). The downside is that the current state of the tooling art is quite primitive. However, there is a lot of vendors doing a lot of really good work in this space.
If you are really motivated to learn what is under the covers, here are some technologies that are a starting point:
a) SOAP. The base messaging mechanism. Check out Apache Axis (www.xml.apache.org/axis (http://xml.apache.org/axis/index.html)
b) WSDL. This is the base IDL for Web services. It is a little strange, but easy to get used to. The best way to learn WSDL is to review the spec (www.w3.org/TR/wsdl) as well as stare at some WSDL examples (www.salcentral.com).
c) UDDI. This is a registry API for Web services. Check this out at www.uddi.org. Get a) and b) down solid before moving to c).
Of course, there are rich resources for Web services on the web. I personally recommend www.ibm.com/developerworks/webservices.
good luck
sgg
Originally posted by L Goundalkar:
Hi All,
Can anyone tell me what are the basic requirements of creating or developing a simple web service.
How a web service is different from RMI, CORBA and so on.
Being a Java developer what are the new technologies I have to learn to start a new ride in Web services.

TIA



------------------
sgg


Steve Graham<BR>Author of <A HREF="http://www.amazon.com/exec/obidos/ASIN/0672321815/ref=ase_electricporkchop/103-0514572-3811868" TARGET=_blank rel="nofollow">Building Web Services: Making Sense of XML, SOAP, WSDL, and UDDI</A>
Johannes de Jong
tumbleweed
Bartender

Joined: Jan 27, 2001
Posts: 5089
"Web Services consists of SOAP (the protocol for distribution),"
Could SOAP be replaced by MQ of IBM ?.
We are going the web-services way with our internal systems. Basically it will consist out of
  1. The application (could be legacy)
  2. XML as the "interface"
  3. MQ as the "data-bus"

  4. That's the chosen "architecture" in very basic lines, sorry I saw only rough draft . Am I then right that they use MQ as opposed to SOAP.
Stephen Graham
Greenhorn

Joined: Oct 02, 2001
Posts: 11
Johannes:
MQ doesn't replace SOAP. Rather, the positioning to consider would be something like SOAP over MQ (MQ replaces HTTP in this case). Check out the HTTP-R (http reliable) specification. www.ibm.com/developerworks/webservices has some good httpr resources (primer and spec) and the WSTK 2.4.1 has an httpr impl and demo.
sgg
Originally posted by Johannes de Jong:
"Web Services consists of SOAP (the protocol for distribution),"
Could SOAP be replaced by MQ of IBM ?.
We are going the web-services way with our internal systems. Basically it will consist out of
  1. The application (could be legacy)
  2. XML as the "interface"
  3. MQ as the "data-bus"

  4. That's the chosen "architecture" in very basic lines, sorry I saw only rough draft . Am I then right that they use MQ as opposed to SOAP.


------------------
sgg
L Goundalkar
Ranch Hand

Joined: Jul 05, 2001
Posts: 395
Hi All,
Thanks for the information.
Catch you later..

------------------
L Goundalkar
lggoundalkar@hotmail.com
Sun Certified Programmer for Java 2 Platform
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: Basic requirements of WS
 
Similar Threads
Visual Basic to HTML
Webservice and .Com - Have same Fate.
VB Screen to HTML
Visual Basic to HTML
Visual Basic to HTML