SOA for Forms and 4GL Developers: A Simple Web Services and BPEL example

Purpose

In this tutorial, you are introduced to BPEL (Business Process Execution Language) and web services. Using simple examples, you will see how you can publish Java code as web services, orchestrate those web services together into a BPEL service, and then call that BPEL service from your application. You will use JDeveloper and Oracle ADF to build your application with minimum of coding.

Time to Complete

Approximately 60 minutes

Topics

This tutorial covers the following topics:

	Overview
	Scenario
	Installation
	Create application code and Publish as web services
	Orchestrate web services as a BPEL service
	Summary

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Overview

While this example uses very simple coding examples, it shows how you can take functionality from your application and publish as a web services so that other applications can use those services. Then, by orchestrating web services together into a BPEL service, you can provide a richer service which is easily consumed from your application.

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Scenario

The scenario for this application will be kept as simple as possible in order to focus on the elements of the technology; however once you have an understanding of the simple case it can be easily applied to more "real world" examples. The scenario is to create two simple Java classes, both take a string input and return a string output. The first will accept a string and return the string prefixed with "Hello ". The second Java class will accept a string and then concatenate"how are you?". Finally, these two web services will be orchestrated together such the the first is called and then passes the result to the second. So, given the initial input of "John Doe" the result will be "Hello John Doe, how are you?

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Installation

The first step of this tutorial will be to install the relevant software. The instructions are based on Oracle JDeveloper 10.1.3.1 Developer Preview and SOA Suite 10.1.3.1 Preview.

	Installing the SOA Suite 10.1.3.1 Preview
	Installing JDeveloper 10.1.3.1. Preview
	Creating Connections

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Installing the SOA Suite 10.1.3.1 Preview

In this section of the document we assume that Winzip is installed on the computer. You will unzip and install the application server that will run your web and BPEL services.

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Installing Oracle JDeveloper 10.1.3.1 Preview

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Creating Connections

You will now create connections to the SOA suite application server.

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Create application code and publish as web services

Create the Application

You will now create the application in which your business logic code will be placed.

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Create Java Classes

In this section you create two Java classes that will do simple string manipulation.

1.	Create the Java class which will take a string and output "Hello" + string Right-click the WebService project in the Applications Navigator, and click New... in the context menu and select Java Class from the New Gallery. In the Create Java Class dialog enter a class name helloWorld and keep the defaults for the other fields then click OK.
2.	In the code editor add a new method: public String sayHello (String x){ return "Hello "+ x; } Click ctrl+F9 or the Make to ensure the class compiles.
3.	Create the Java class which will take a string and output; string + "how are you?" Right-click the WebService project in the Applications Navigator, and click New ... in the context menu and select Java Class from the New Gallery. In the New Java Class dialog enter a class name howAreYou and keep the defaults for the other fields then click OK.
4.	In the code editor add a new method: public String sayHowAreYou (String x){ return x+ ", how are you?"; } Click ctrl+F9 or the Make button to ensure the class compiles.
5.	Click Save All or select File | Save All to save your work.

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Publish as web Services

You will now publish these two classes a web services.

1.	In the Applications Navigator, right-click the helloWorld Java class you created earlier and choose Create J2EE Web Service... from the context menu.
2.	In the Select J2EE Web Service Version dialog select J2EE 1.4 Click OK.
3.	In the step 1 of 8 in the dialog enter the Web Service Name helloWorldWS, leave other fields as default. You can now click Finish since you will be accepting all the defaults.
4.	Repeat steps 1-3 for the howAreYou Java class, naming this web Service howAreYouWS
5.	Click Save All or select File | Save All to save your work.
6.	Finally, you need to deploy the web services to the Application Server. In the Applications Navigator, right-click the WebServices.deploy node choose Deploy To and then the name of your Application Server connection Click OK on the Configure Application dialog and check you get a successful deployment message in the deployment log.

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Test the web Services

Using the application server management page, you will test the web services.

1.	To test the web services you need to create a client stub which is based on the WSDL of the deployed web service. Alternatively, you can use the features of Oracle Enterprise Manager to test your services. From your Windows desktop select Start, Programs, <App Server Instance>, Launch SOA Console.
2.	Click the link Application Server Control on the top right of the page .
3.	If prompted, enter the username and password Click OK.
4.	Click the Home link under the Members heading.
5.	Click the Web Services link
6.	Find the name of the web Service you created and click on that name
7.	Click the Test Service link
8.	At this point, copy the URL of the web Service to notepad. You will need to use this URL in a later step. Click the Test Web Service button.
9.	Enter a string in the parameter field and click Invoke
10.	The resulting page will show the XML message including the resulting string form the web Service which concatenates the input parameter with "Hello"
11.	Repeat with the second web Service to ensure the correct result.

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Orchestrate web services as BPEL Services

In this sessions you will orchestrate the web services such that the output of one web service is the input to the other web service . To do so, perform the following steps:

	Create the Application
	Define the BPEL Process
	Deploy the BPEL Process
	Testing the Application

Create the Application

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Define the BPEL Process

In this section you will create a BPEL service by diagrammatically"hooking" up the flow from the various web services.

1.	This next stage is to "hook" the web services into a flow and indicate how the data is passed from one web service to the next. If the BPEL Process diagram has not appeared then double-click on the SimpleBPEL.bpel node under the HandsOnBPELProcess project.
2.	From the component palette, drag a Scope component onto the BPEL diagram between the ReceiveInput and ReplyOutput nodes (Ensure All Process Activities is selected in the component palette drop down).
3.	From the component palette, drag a Partner Link component onto the right hand "swim lane" of the BPEL diagram. This is the "node" that will represent one of your web services.
4.	In the Create Partner Link dialog paste in the URL of the sayHello web service (as saved earlier) and append with "?wsdl" and tab out the field
5.	If a dialog appears indicating: "There are no Partner Link Types defines in current WSDL, do you want to create a new WSDL file that will by default create Partner Link Types for you?" click Yes.
6.	Set the Partner Role to helloWebService_Role Click OK.
7.	Repeat steps 2-6 for howAreYouWS
8.	Click the + on the Scope node to expand it. From the component palette drop two Invoke nodes into the newly expanded Scope area. Double-click on the name of each and call the first invokeHello and the second invokeHowAreYou. These are the BPEL invoke actions that will call your web services.
9.	Drag the arrow from the invokeHello node to the helloWorthWebService partner link in the right hand swim lane
10.	In the Edit Invoke dialog click the Automatically Create Input Variable button and the Automatically Create Output Variable button. Accept the default values in the Create Variable dialog. In this step, you are creating two variables: one to represent the input to the invoke action, and one to represent the output from the invoke. Click OK.
11.	Drag the arrow from the invokeHowAreYou node to the howAreYouWebService partner link in the right hand swim lane
12.	In the Edit Invoke dialog click the Automatically Create Input Variable button and the Automatically Create Output Variable button. Accept the default values in the Create Variable dialog. Click OK.
13.	From the component palette, drag an Assign component and place it before invokeHello, name it Assign_1. Repeat and place one before invokeHowAreYou and after invokeHowAreYou; calling them Assign_2 and Assign_3 respectively.
14.	Double-click on Assign_1. Select the Copy Operation tab and click Create and then Copy Operation
15.	In the Create Copy Operation dialog, in the left hand From list, expand inputVariable to its most granular node (client:input) and select that node.
16.	In the right hand To list,expand the tree to find the name of the input parameter to the invokeHello node to its most granualar node and select that node. Click OK on to close the Create Copy Operation and then click OK to close the tabbed dialog.
17.	Repeat steps 14-16 for Assign_2 and Assign_3. Ensure that the value defined in the From list is the output parameter from the previous invoke node. And that the value defined in the To list is the input to the next invoke node. For Assign_3 the value defined in the To list should be outputVariable Click OK on to close the Create Copy Operation and then click OK to close the tabbed dialog.
18.	Click Save All or select File | Save All to save your work.

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Deploy the BPEL Process

Now that you have orchestrated a number of web Services into a single BPEL service, you need to deploy that service to your application server

To deploy the BPEL service, perform the following steps:

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Testing the Application

The final step is to show that this BPEL service can now be easily consumed from your own application code.

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Summary

You have used this simple example to publish business code as web services, and to then combine those web services into a BPEL service which can then be called from any application.

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