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XML Reference Guide

📄 Contents

  1. XML Reference Guide
  2. Overview
  3. What Is XML?
  4. Informit Articles and Sample Chapters
  5. Books and e-Books
  6. Official Documentation
  7. Table of Contents
  8. The Document Object Model
  9. Informit Articles and Sample Chapters
  10. Books and e-Books
  11. Official Documentation
  12. DOM and Java
  13. Informit Articles and Sample Chapters
  14. Books and e-Books
  15. Implementations
  16. DOM and JavaScript
  17. Using a Repeater
  18. Repeaters and XML
  19. Repeater Resources
  20. DOM and .NET
  21. Informit Articles and Sample Chapters
  22. Books and e-Books
  23. Documentation and Downloads
  24. DOM and C++
  25. DOM and C++ Resources
  26. DOM and Perl
  27. DOM and Perl Resources
  28. DOM and PHP
  29. DOM and PHP Resources
  30. DOM Level 3
  31. DOM Level 3 Core
  32. DOM Level 3 Load and Save
  33. DOM Level 3 XPath
  34. DOM Level 3 Validation
  35. Informit Articles and Sample Chapters
  36. Books and e-Books
  37. Documentation and Implementations
  38. The Simple API for XML (SAX)
  39. Informit Articles and Sample Chapters
  40. Books and e-Books
  41. Official Documentation
  42. SAX and Java
  43. Informit Articles and Sample Chapters
  44. Books and e-Books
  45. SAX and .NET
  46. Informit Articles and Sample Chapters
  47. SAX and Perl
  48. SAX and Perl Resources
  49. SAX and PHP
  50. SAX and PHP Resources
  51. Validation
  52. Informit Articles and Sample Chapters
  53. Books and e-Books
  54. Official Documentation
  55. Document Type Definitions (DTDs)
  56. Informit Articles and Sample Chapters
  57. Books and e-Books
  58. Official Documentation
  59. XML Schemas
  60. Informit Articles and Sample Chapters
  61. Books and e-Books
  62. Official Documentation
  63. RELAX NG
  64. Informit Articles and Sample Chapters
  65. Books and e-Books
  66. Official Documentation
  67. Schematron
  68. Official Documentation and Implementations
  69. Validation in Applications
  70. Informit Articles and Sample Chapters
  71. Books and e-Books
  72. XSL Transformations (XSLT)
  73. Informit Articles and Sample Chapters
  74. Books and e-Books
  75. Official Documentation
  76. XSLT in Java
  77. Java in XSLT Resources
  78. XSLT and RSS in .NET
  79. XSLT and RSS in .NET Resources
  80. XSL-FO
  81. Informit Articles and Sample Chapters
  82. Books and e-Books
  83. Official Documentation
  84. XPath
  85. Informit Articles and Sample Chapters
  86. Books and e-Books
  87. Official Documentation
  88. XML Base
  89. Informit Articles and Sample Chapters
  90. Official Documentation
  91. XHTML
  92. Informit Articles and Sample Chapters
  93. Books and e-Books
  94. Official Documentation
  95. XHTML 2.0
  96. Documentation
  97. Cascading Style Sheets
  98. Informit Articles and Sample Chapters
  99. Books and e-Books
  100. Official Documentation
  101. XUL
  102. XUL References
  103. XML Events
  104. XML Events Resources
  105. XML Data Binding
  106. Informit Articles and Sample Chapters
  107. Books and e-Books
  108. Specifications
  109. Implementations
  110. XML and Databases
  111. Informit Articles and Sample Chapters
  112. Books and e-Books
  113. Online Resources
  114. Official Documentation
  115. SQL Server and FOR XML
  116. Informit Articles and Sample Chapters
  117. Books and e-Books
  118. Documentation and Implementations
  119. Service Oriented Architecture
  120. Web Services
  121. Informit Articles and Sample Chapters
  122. Books and e-Books
  123. Official Documentation
  124. Creating a Perl Web Service Client
  125. SOAP::Lite
  126. Amazon Web Services
  127. Creating the Movable Type Plug-in
  128. Perl, Amazon, and Movable Type Resources
  129. Apache Axis2
  130. REST
  131. REST Resources
  132. SOAP
  133. Informit Articles and Sample Chapters
  134. Books and e-Books
  135. Official Documentation
  136. SOAP and Java
  137. Informit Articles and Sample Chapters
  138. Books and e-Books
  139. Official Documentation
  140. WSDL
  141. Informit Articles and Sample Chapters
  142. Books and e-Books
  143. Official Documentation
  144. UDDI
  145. UDDI Resources
  146. XML-RPC
  147. XML-RPC in PHP
  148. Informit Articles and Sample Chapters
  149. Books and e-Books
  150. Official Documentation
  151. Ajax
  152. Asynchronous Javascript
  153. Client-side XSLT
  154. SAJAX and PHP
  155. Ajax Resources
  156. JSON
  157. Ruby on Rails
  158. Creating Objects
  159. Ruby Basics: Arrays and Other Sundry Bits
  160. Ruby Basics: Iterators and Persistence
  161. Starting on the Rails
  162. Rails and Databases
  163. Rails: Ajax and Partials
  164. Rails Resources
  165. Web Services Security
  166. Web Services Security Resources
  167. SAML
  168. Informit Articles and Sample Chapters
  169. Books and e-Books
  170. Specification and Implementation
  171. XML Digital Signatures
  172. XML Digital Signatures Resources
  173. XML Key Management Services
  174. Resources for XML Key Management Services
  175. Internationalization
  176. Resources
  177. Grid Computing
  178. Grid Resources
  179. Web Services Resource Framework
  180. Web Services Resource Framework Resources
  181. WS-Addressing
  182. WS-Addressing Resources
  183. WS-Notifications
  184. New Languages: XML in Use
  185. Informit Articles and Sample Chapters
  186. Books and e-Books
  187. Official Documentation
  188. Google Web Toolkit
  189. GWT Basic Interactivity
  190. Google Sitemaps
  191. Google Sitemaps Resources
  192. Accessibility
  193. Web Accessibility
  194. XML Accessibility
  195. Accessibility Resources
  196. The Semantic Web
  197. Defining a New Ontology
  198. OWL: Web Ontology Language
  199. Semantic Web Resources
  200. Google Base
  201. Microformats
  202. StructuredBlogging
  203. Live Clipboard
  204. WML
  205. XHTML-MP
  206. WML Resources
  207. Google Web Services
  208. Google Web Services API
  209. Google Web Services Resources
  210. The Yahoo! Web Services Interface
  211. Yahoo! Web Services and PHP
  212. Yahoo! Web Services Resources
  213. eBay REST API
  214. WordML
  215. WordML Part 2: Lists
  216. WordML Part 3: Tables
  217. WordML Resources
  218. DocBook
  219. Articles
  220. Books and e-Books
  221. Official Documentation and Implementations
  222. XML Query
  223. Informit Articles and Sample Chapters
  224. Books and e-Books
  225. Official Documentation
  226. XForms
  227. Informit Articles and Sample Chapters
  228. Books and e-Books
  229. Official Documentation
  230. Resource Description Framework (RDF)
  231. Informit Articles and Sample Chapters
  232. Books and e-Books
  233. Official Documentation
  234. Topic Maps
  235. Informit Articles and Sample Chapters
  236. Books and e-Books
  237. Official Documentation, Implementations, and Other Resources
  238. Rich Site Summary (RSS)
  239. Informit Articles and Sample Chapters
  240. Books and e-Books
  241. Official Documentation
  242. Simple Sharing Extensions (SSE)
  243. Atom
  244. Podcasting
  245. Podcasting Resources
  246. Scalable Vector Graphics (SVG)
  247. Informit Articles and Sample Chapters
  248. Books and e-Books
  249. Official Documentation
  250. OPML
  251. OPML Resources
  252. Summary
  253. Projects
  254. JavaScript TimeTracker: JSON and PHP
  255. The Javascript Timetracker
  256. Refactoring to Javascript Objects
  257. Creating the Yahoo! Widget
  258. Web Mashup
  259. Google Maps
  260. Indeed Mashup
  261. Mashup Part 3: Putting It All Together
  262. Additional Resources
  263. Frequently Asked Questions About XML
  264. What's XML, and why should I use it?
  265. What's a well-formed document?
  266. What's the difference between XML and HTML?
  267. What's the difference between HTML and XHTML?
  268. Can I use XML in a browser?
  269. Should I use elements or attributes for my document?
  270. What's a namespace?
  271. Where can I get an XML parser?
  272. What's the difference between a well-formed document and a valid document?
  273. What's a validating parser?
  274. Should I use DOM or SAX for my application?
  275. How can I stop a SAX parser before it has parsed the entire document?
  276. 2005 Predictions
  277. 2006 Predictions
  278. Nick's Book Picks

One of the great features designed into Web services has been the notion that you can create a service automatically; in other words, you can type a few commands, and automatically create a client for service you want to access. This single capability is perhaps the greatest reason Web services are taken off as they have; without it, we'd all have to hand code to a fairly complicated specification.

So any tool that makes it easier to create clients is welcome; one that also allows us to easily create services is even more welcome. This month saw the release of Apache Axis2 1.0. The successor to the popular Apache Axis project, Axis2 has been completely rebuilt from the ground up. It includes the following features:

  • Support for SOAP 1.1, SOAP 1.2, and REST
  • Support for WSDL code generation, and no matter what the encoding/style
  • Support for all message exchange patterns
  • Support for both synchronous and asynchronous service clients
  • Hot deployment of both the application and services
  • The ability to obtain a service's WSDL, schema, and even policies easily
  • Support for multiple transports, including HTTP, JMS, SMTP, and TCP

Axis2 also includes support for other standards, such as:

  • Apache's new object model, AXIOM
  • WS-Addressing (both the submission and final versions)
  • WS-Policy
  • WS-ReliableMessaging
  • WS-Coordination
  • WS-AtomicTransaction
  • WS-Security
  • WS-Addressing

Axis2 is built on a modular structure, enabling extension usually modules that can be enabled or disabled at both the application and the service-level. For example, at the time of this writing, modules provide support for the following recommendations:

  • WS-ReliableMessaging
  • WS-Coordination
  • WS-AtomicTransaction
  • WS-Security
  • WS-Addressing

All right, so how do you actually do something with Axis2? Let's start with how easy it is to create an actual service. Consider, for example, a simple Java class:

package com.informit.xmlguide.candy;

public class InventoryService{

    public OMElement getInventory(OMElement prodInfo){
       //Extract product number from prodInfo element and
       //return current inventory as an element
    }

    public void updateInventory(OMElement invInfo){
       //Extract the product number and new inventory 
       //value from invInfo element and act on it.
    }

}

This is a simple class, with just two methods. The first, getInventory(), is a traditional request-response method. You send it information in the form of an OMElement -- part of the AXIOM framework, this is essentially just an XML element -- and it does some processing and returns another OMElement. The second, updateInventory(), is an "in only" request, in that it doesn't return any information at all.

The process of turning this into a Web service is pretty straightforward. Once we have a class that compiles, virtually all we need is a service.xml file:

<service>
    <description>

        This is the inventory service, providing opportunities to 
        both update and request inventory information.
    </description>
    <parameter name="ServiceClass" locked="false">com.informit.xmlguide.candy.InventoryService</parameter>
    <operation name="getInventory">
        <messageReceiver class="org.apache.axis2.receivers.RawXMLINOutMessageReceiver"/>

        <actionMapping>urn:getInventory</actionMapping>
    </operation>
     <operation name="updateInventory">
        <messageReceiver class="org.apache.axis2.receivers.RawXMLINOnlyMessageReceiver"/>

        <actionMapping>urn:updateInventory</actionMapping>
    </operation>
 </service>

The service.xml file tells Axis2 about the service. It points out the class and the methods to be turned into operations. It also specifies whether the service should use a "in-out" receiver, or an "in only" receiver.

To actually deploy the service, you will need a "Axis2 Archive file", or .aar. Don't panic, though, it's just a jar file. To create it, lay out your files as follows:

/service
    /META-INF
        service.xml
    InventoryService.class

You can then execute the following command from the serivce directory:

jar -cf InventoryService.aar .

Deploying the service is a matter of uploading it to the Axis2 application. The application, which comes packaged as the axis2.war file, must be deployed to a container such as Apache Tomcat or Apache Geronimo. From there, access the Axis2 administration application by pointing your browser to:

http://localhost:8080/axis2
Axis2 home page

Click the "Administration" link and log in with the default information, admin/axis2. The Administration page gives you the opportunity to control many aspects of the Axis2 application, including service parameters and modules. It also gives you the opportunity to "hot deploy" a service to the running application without having to restart the web application server.

Axis2 uploading

Click "Upload service" and browse to the .aar file you created earlier. Click "Upload". You can see the new service by clicking on the "Available sources" link:

Axis2 services

Notice that not only did Axis2 create the service, it created both a SOAP service and a REST service.

Axis2 also enables you to easily create services and clients from WSDL files. For example, if we had started with a WSDL file instead of a Java class, we could create the service by running the WSDL2Java script, located in the axis2/bin directory:

WSDL2Java -uri InventoryService.wsdl -ss -sd -p com.informit.xmlguide.candy
-d xmlbeans -o service

In this case, we are telling the script to take the inventoryService.wsdl file and generate both the server side and service description files, placing the classes in the com.informit.xmlguide.candy package and using Apache's xmlbeans as the data binding method. The output goes to the service directory.>

This process can generate over 200 files, but the only one you're worried about is the "skeleton" file, in which you implement the actual service. For example:

package com.informit.xmlguide.candy;

public class InventoryServiceSkeleton{

    public  com.informit.xmlguide.candy.xsd.GetInventoryReturnDocument getInventory (com.informit.xmlguide.candy.xsd.GetInventoryParamDocument param0 )
         
    {
          //Implement the service here using data binding
          //and return a GetInventoryReturnDocument object
    }
     
    public  void updateInventory (com.informit.xmlguide.candy.xsd.UpdateInventoryParamDocument param2 )
         
    {
        //Implement the service
    }
     
}

Once you implement the service, you need to create the .aar file:

set ANT_HOME=e:\apache-ant-1.6.5
PATH=%PATH%;%ANT_HOME%\bin;
set AXIS2_HOME=e:\axis2
cd service
ant jar.service

As I said, the generation process creates a large amount of files, so you wouldn't want to have to compile them by hand. Fortunately, the generation process also creates a build.xml file for Apache Ant to use to compile the service. The end result is the InventoryService.aar file, which you deploy as before.

Creating a client can be just a simple. Again, you can use the WSDL2Java script:

WSDL2Java -uri ClassifiedService.wsdl -p com.informit.xmlguide.candy -d xmlbeans -o client

In this case, the important file is the "stub", which you can then use to create a client, as in:

package com.informit.xmlguide.candy;

import axis2.apache.org.xsd.*;

public class CandyClient{

   public static void main(java.lang.String args[]){

      try{
         InventoryServiceStub stub = 
              new InventoryServiceStub(null,
     "http://localhost:8080/axis2/services/InventoryService");
            
         GetInventoryRequestDocument invReqDoc = 
               GetInventoryRequestDocument.Factory.newInstance();

         GetInventoryRequestDocument.GetInventoryRequest invReq = 
                              invReqDoc.addGetInventoryRequest();
         invReq.setProductID("THX1138");
 
         GetInventoryResponseDocument invResDoc = 
                                       stub.getInventory(invReqDoc);
         System.out.println("Inventory:  "+
                invResDoc.getGetInventoryResponse().getInventory());

      } catch(Exception e){
         e.printStackTrace();
      }
   }
}

These classes are generated by the WSDL2Java script. The client can also be compiled by Ant, this time using the jar.client target.

Of course, this is just a cursory look at what Apache Axis2 can do. For more information, check out the resources that follow.

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