+1!!! -----Original Message----- From: Anderson Jonathan [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 12, 2004 11:03 AM To: [EMAIL PROTECTED] Subject: RE: Best Practices?
I would venture to say that 80% of the complications and frustrations implementing interoperable (WS-I compliant Doc/Literal) SOAP web services on Java platforms stem from the XML datatype to Java datatype binding problem. If you take the time to learn W3C XML Schema, you'll see the problem: it's not an OO type system. Therefore modeling your data types in Java and expecting some automagic Java2WSDL utility to do all of the hard work to generate your XML schema is naive, and it is unfortunate that so many OO developers think this way. I've encountered several approaches for dealing with this problem with Axis - virtually all of them involve hand crafting your WSDL and XSD (with a WSDL/XSD IDE, of course) and generating a Java type system using ***a particular Java XML binding engine***. Using Axis's internal XML binding engine is one of several options available to you. For more info on the XML binding problem in Java, I defer to Dennis Sosnoski (www.sosnoski.com), a long-time XML deep thinker. He first turned me onto the XML data binding "problem" with his excellent articles (4 parts) on the issues over at IBM developerWorks. http://www-106.ibm.com/developerworks/library/x-databdopt/index.html If you're trying to use Axis's internal XML binding engine, here's some advice: http://marc.theaimsgroup.com/?l=axis-user&m=107945370506044&w=2 We've since moved away from this approach, and are currently using Axis's Message Style services to pass the SOAP Request Body DOM straight to Castor, which unmarshalls the XML into a Castor generated type system. We further introduced a broker pattern to abstract the SOAP messaging layer from our business layer, which currently is not tied to any XSD generated types. Axis Message Style Service Implementation -> Service Broker Layer (unmarshalls SOAP Request DOM via Castor, extracts the necessary information from Castor types - literally traversing the graph's getters - to invoke Business Manager Layer, and catches Business Exceptions and maps them to proper SOAP Faults using AxisFault)-> Business Manager Layer (not tied to XSD types, but rather pure Java business domain types, invokes DAO layer as needed) -> DAO Layer (a Spring/Hibernate layer to manage persistence for business domain types) The problem here is definitely managing and translating between the two type systems: Castor generated classes from XSD and non-generated Business Domain classes. The alternative, however, is to just try to use the XSD generated type system and persist that directly. This is too big of a leap for us right now, as our business layer doesn't "think" in pure XSD type terms. You'll probably encounter this a lot given how much legacy functionality people are trying to SOAP service enable. Bottom line: implementing a WS-I compliant SOAP service in Java is not a trivial thing. There are two types of people building Web Services in Java: those who are extremely frustrated with the completely stupid state of the Java based Web Services world right now and yet still trying very hard to do it right, and those who haven't grasped that world is in a completely stupid state right now. -Jon -----Original Message----- From: Joe Plautz [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 12, 2004 10:02 AM To: [EMAIL PROTECTED] Subject: Re: Best Practices? My first attemps have started with a WSDL/Schema then I generate everything. I was able to find an example at W3.org and I just manipulate it to the way I need it. I thought this to be the best way at the time because of interoperability. >From what I've been finding thus far there are no "Standard" practices, just "Accepted" practices. Starting with a class then using Java2WSDL and then WSDL2Java seems to be the most common. But, it almost seems that this was not the intention of the designers of Axis. Why use two steps when you can use one? Creating a WSDL from scratch seems like the intended way, but is not the most accepted way by the developers/users of Axis. Why write what you can generate? I know this isn't difficult earth shattering stuff, I'm just looking for the best way of doing this. So, when I start working with other people to create services, we're doing it the "right" way. ----- Original Message ----- From: "Dorner Thomas" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, May 12, 2004 7:01 AM Subject: AW: Best Practices? You are right - if you will do a interoperable webservice that deal with other clients (.Net ...) its better to go from the wsdl. But when i use String, int and so on and i generate a wsdl by java2wsdl, I hope the wsdl i get, depends on the standard spec. for wsdl!???? So there should no problem to use the wsdl by other languages!??? Dont know how it looks with complex datatypes!???? Do you all write your own wsdl by hand???? Tomi -----Ursprüngliche Nachricht----- Von: David Cunningham [mailto:[EMAIL PROTECTED] Gesendet: Mittwoch, 12. Mai 2004 13:14 An: [EMAIL PROTECTED] Betreff: RE: Best Practices? I disagree, the right way is to start with your WSDL and schema files. If you want any hope of being WS-I compliant or using doc/literal this is your best bet. As soon as you start with an interface, you start dealing Java types that do not correlate to schema types very well. For example, if you use: public List getStuff() or public String[] getStuff(), you will either generate a WSDL file that can't be parsed properly by other consumers (.NET, Glue, etc) or be bound to Java collection types that have no chance of being parsed properly by .Net (without a lot of hacking around). My recommendation, again personal preference, is always give thought to the XML that is going across the wire and what you are trying to send/receive and in what structure. This is especially important when dealing with doc/literal since you are sending a single document over the wire. - david -----Original Message----- From: Dorner Thomas [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 12, 2004 2:03 AM To: '[EMAIL PROTECTED]' Subject: AW: Best Practices? The right way is to write a interface which includes all the Methods your webservice should offer. Then you use java2wsdl to generate your wsdl. You have to correct your parameternames in your auto generated wsdl, cause the the params looks like in0, in1, in2... . Then you use wsdl2java to generate your stub, locator, skeleton, impl and maybe a testclient. Now you can implement and deploy your Service by unsing the addtional generated .wsdd files. Hope this helps you Tomi -----Ursprüngliche Nachricht----- Von: Joe Plautz [mailto:[EMAIL PROTECTED] Gesendet: Dienstag, 11. Mai 2004 18:48 An: [EMAIL PROTECTED] Betreff: Best Practices? I'm a newbie looking for guidance in creating WebServices with Axis. I've gone through the documentation backwards and forwards and have come up with me own ways of doing things. I start with a WSDL that I create and use WSDL2Java to generate the code and go from there. What I'm looking for is a best practices because I don't feel confident in the way I am going about it. Do most people start from a WSDL? Do people generate a WSDL from an interface and go from there? Do people just create a class and a WSDD file? Or, do people use JWS files that accept a string and the string contains xml formated text? If there are any sites that cover this information, please forward them on to me. Any help will be appreciated!!! Thanks, Joe Plautz [EMAIL PROTECTED]
