1. Developing Web Services with the Eclipse Web Tools Platform
Boris Minkin

2. Web Services? What and why?
Companies need to integrate existing systems – achieve interoperability among disparate implementations
Web Services and XML came along with the ability to provide standard communication interface between these systems
They are essentially language/platform-neutral remote procedure calls built on HTTP infrastructure

3. Fundamental standards and technologies
XML – eXtensible Markup Language: The syntax used for Web Service messages, configuration files, description files, etc.
HTTP – Hypertext Transfer Protocol: The standard transport used to communicate between Web Service servers and clients
RPC – Remote Procedure Call: The technique of executing a method call remotely—here, the client calling a web service’s operation.

4. Web Service standards and technologies
SOAP – Simple Object Access Protocol. An XML-based standard for sending messages (in a SOAP envelope) between web services and clients.
WSDL—Web Service Definition Language XML-based description of a web services public interface. (Similar to CORBA IDL.)
UDDI—Universal Description, Discovery and Integration. And XML-based registry for web service. Interrogated with SOAP messages, returns WSDL documents.
CORBA: Common Object Request Broker Architecture

5. Locating and Using Web Services
UDDI Registry
Query registry
Obtain WSDL
Publish WSDL
Get result back
Client Application
Web Service
Call web service
operation

6. Java Web Service related standards and protocols
Web Services are Part of J2EE 1.4
Web Services for Java: JSR 101/109 standard
One can generate web service from Java Bean or Stateless Session EJB
Various Protocols and Standards:
JAXP—Java API for XML Processing
JAX-RPC—Java API for XML-based RPC
JAXR—Java API for XML registries
SAAJ—SOAP with Attachments API for Java
SAX—Simple API for XML processing
DOM API—Document Object Model API

7. What is Eclipse?
Open-Source Java Integrated Development Environment (IDE)
Initially donated by IBM to the Open-Source foundation
Includes:
Java Development Tools (JDT)
Integrated Testing and Debugging Support
Incremental compilation and build
Team development support
CVS support comes out of the box
Pluggable – major advantage – can develop custom plug-ins – variety is available at sites such as:

8. Eclipse main concepts Workspace Project Workbench Perspective
A workspace is a place where Eclipse stores the user’s data.
It’s a tree with projects, folders and files.
A workspace can contains many projects
You can have several workspaces but only one workspace can be activated at a time.
Project
Collection of folders and files
Workbench
The workbench is the development environment window contains one or more perspectives
Perspective
A layout with a set of editors and views
Some Perspectives include: Java, CVS, Debug, Resource, etc.
Editor/View
Editors allow to edit content of a particular type (e.g., Java code editor)
Views present information in non-editable way (some views include Ant, Console, Declaration, Error log, Hierarchy, Javadoc, Navigator, Outline, Package Explorer, Problems, Search

9. Eclipse Web Tools Project (WTP) Platform
One of the top Eclipse projects
Adds Web/J2EE/Web Services development facilities
J2EE and Web perspectives
Web, EJB and Enterprise Application projects
Variety of editors and views for editing JSP/HTML, XML, other files
Provides tools for:
Web applications using JSP / Servlets
Provides editors for XML, HTML, JSP, JavaScript
Enterprise Java Beans (EJB)
Web Service (based on Apache AXIS)
Database exploration
Support for servers such as Tomcat, JBoss, etc.
WTP Roadmap:
WTP 0.7, July 2005 – End User Tools
WTP 1.0, December 2005 – Platform APIs
WTP 1.5, June 2006 – Java EE 5.0

10. Two ways to create Web Service with Eclipse WTP
Bottom up:
You create the web service Java Bean or Stateless Session EJB
Eclipse creates the glue classes and the WSDL
Top down:
You write the WSDL
Eclipse creates the necessary glue classes and the service’s method stubs in a Java Bean
You implement the operations

11. Eclipse WTP – Web Services Tools
Wizard to create Web service top-down (from WSDL) and bottom-up (from Java).
Wizard creates a Java stub that binds to a Web service.
Wizard can optionally configure test client and deployment of your Web service
You can also specify to monitor your web service once its launched

12. Eclipse WTP – Web Services Tools
Graphical WSDL/XSD Editor
Edit your WSDL file without wrestling with the syntax
Collections of
related ports
Abstract sets of one or more operations supported by one or more ports.
Containers for data type definitions using XML schema type system
Concrete protocol and data format specifications for a particular port type
Graphical WSDL editor helps one to edit WSDL files. Every WSDL file includes the following major interrelated entities that describe every web service:
Types: A container for data type definitions using XML schema type system.
Messages: An abstract, typed definition of the data being communicated. A message can have one or more typed parts, for example the highlighted message getLatestDateTimeResponse has just one part which is its return parameter of xsd:date (XML Schema date type).
Port types: Abstract sets of one or more operations supported by one or more ports.
Operations: Abstract description of an action supported by the service that defines the input and output message as well as optional fault message.
Bindings: Concrete protocol and data format specification for a particular port type. The binding information contains the protocol name, the invocation style, a service ID, and the encoding for each operation.
Services: A collection of related ports.
Ports: Single endpoint, which is defined as an aggregation of a binding and a network address.
Abstract, typed definitions of the data being communicated.
A message can have one or more typed parts, for example the highlighted message getLatestDateTimeResponse has just one part which is its return parameter of xsd:date (XML Schema date type).

13. Eclipse WTP – Web Services Tools
XML Schema, WSDL, and WS-I validators
Ensure your documents conform to standards (WSDL, XSD) and standard extensions (WS-I)

14. Eclipse WTP – Web Services Tools
Web Service Explorer
Publish/Discover Web services.
Invoke Web services dynamically. No code generation required for testing.
One can go ahead and specify method parameters to invoke them

15. Eclipse WTP – Web Services Tools
TCP/IP Monitor is a powerful facility to show data sent through the wire and to simplify analysis of any possible problems
Shows the list of interactions (request/response) that have been performed in the chronological order.
When a developer clicks on the particular interaction, the system displays the time of request, how long it took the system to respond (in milliseconds) and type of protocol that was used (usually, HTTP).
Displays the SOAP
response envelope
Displays the contents of SOAP envelope
generated by web services request.

16. A First Web Tools Project – Step 1
Before we can make any web services we have to create a Dynamic Web Project in Eclipse.
However, before we can make a dynamic Web Project, we need to configure a target server.

17. A First Web Tools Project – Step 2
Now, we are ready to create our Dynamic Web Project.
Since Tomcat is just a Web Container provider, Web project is enough for it.
For servers such as JBoss or WebSphere, you will need to create Enterprise Application Project.

18. J2EE Scenario – Typical Web Services Application Architecture
Java class accesses data from a database or another source
Java class exposed as a Web service

19. Our Sample Application Description
StockData 1
1..N
stockName
stockSymbol
StockService
getLatestPrice
getLatestVolume
getLatestDateTime
getStockName
getStockSymbol
setStockName
setStockSymbol
getStockHistory
price
volume
dateTime
get/setPrice
get/setVolume
get/setDateTime
Just two Java classes – one for exposing the methods to be called through the service, – another for data gathering

20. Free stuff !!!
You can go ahead and download yourself all the software I’ll use in the demo:
J2SE 5.0 JRE:
Eclipse 3.1.2:
Eclipse Web Tools Project (WTP) 1.0:
You can download the complete set (including Eclipse itself and all required components)
You can also install it using Eclipse Install/Update facility – from Help menu select Software Updates – Find and Install, New Features to Install, then: New Remote Site with any name and URL:
Tomcat 5.0/5.5:

21. Demo – Building Bottom-Up Web Service
Create a web service, bottom-up
Exploring a Web Service using the Web Services Explorer
Exploring generated WSDL using WSDL file editor
Creating a simple client to invoke our web service
Writing our own client
Create a web service, top down
See here for WTP update instructions:
Check out

22. Invoke our Web Service from Java command line application
package services;
/**
* Creating a simple Java client to invoke Web Service through the generated service locator and
* service end point interface. */
public class StockServiceClient {
* To invoke stock service
public static void main(String[] args) {
try{
StockServiceServiceLocator wsl = new StockServiceServiceLocator();
StockService ws = (StockService) wsl.getStockService();
String name = ws.getStockName();
System.out.println("Stock name: " + name);
double price = ws.getLatestPrice();
System.out.println("Stock price: " + price);
long volume = ws.getLatestVolume();
System.out.println("Stock volume: " + volume);
} catch (Exception e) {
e.printStackTrace(); }

23. Invoke our Web Service from Microsoft .NET client
Demonstrates Web Services Interoperability
Using Microsoft .NET 1.1 framework generation and compilation tools
Sample program I’ve written in C#

24. To get more information…
WTP website
WTP newsgroup news://news.eclipse.org/eclipse.webtools
WTP Community Resources (articles, tutorials, events)
Article in Eclipse Developer Journal – Developing Web Services with Eclipse WTP: