BPEL Process with multiple Operations / Pick Activity / BPEL Process in Top-down approach

Topics covered:

1. Developing a BPEL process which can expose multiple operations to its clients or handle multiple messages request from clients

2. Developing the BPEL process in Top – Down approach

3. Having a pick activity as the first activity in BPEL process

4. Developing a BPEL process Based on WSDL

5. Developing XSD and WSDL

Sample Description:

    Implementing the Calculator service which exposes 4 operations( addition, subtraction, multiplication, division) which takes 2 parameters as input and returns value. Use BPEL to implement the Calculator service and expose it as service so that client can any operations of his choice

Sample implementation

1. Create a SOA Project with empty composite

Click Finish.

2. Creating XSD

1. Right click the PickProject –> New –> In “New Gallery” window select “All Technologies” Tab –> In “General” Section select XML –> Select “XML Schema” –> click OK

   

2. Specify the File name, directory and target namespace –> click OK

   

3. Create the elements as below

   

   <?xml version=”1.0″ encoding=”utf-8″ ?>

   <xsd:schema xmlns:xsd=”http://www.w3.org/2001/XMLSchema&#8221;

   xmlns=”http://www.manohar.org&#8221;

   targetNamespace=”http://www.manohar.org&#8221;

   elementFormDefault=”qualified”>

   <xsd:element name=”calculatorInput”>

   <xsd:complexType>

   <xsd:sequence>

   <xsd:element name=”inputParam1″ type=”xsd:int”/>

   <xsd:element name=”inputParam2″ type=”xsd:int”/>

   </xsd:sequence>

   </xsd:complexType>

   </xsd:element>

   <xsd:element name=”calculatorOutput”>

   <xsd:complexType>

   <xsd:sequence>

   <xsd:element name=”output” type=”xsd:int”/>

   </xsd:sequence>

   </xsd:complexType>

   </xsd:element>

   </xsd:schema>

   3. Develop a WSDL with 4 operations (addition, subtraction, multiplication, division)

4. Right click PickProject –> New –> All Technologies –> Web services –> WSDL Document –> OK
   

   
   
   

5. Specify WSDL name, Directory and Target Namespace
   

   

   Click OK

   
   
   

6. Create a Messages by clicking “+” in message section
   

   

   Enter the Message Name –> Click OK

   

   
   

7. Create a part element inside the “addInputMsg”.
   

   – Simple way of doing this by dragging and dropping the “CalculatorInput” element from Calculator.xsd on the “addInputMsg”.
   

   – To do this keep “Calculator.xsd” and “Calculator.wsdl” in 2 different window side-by-side as below

   

   Know drag and drop the “CalculatorInput” element from XSD on to “addInputMsg” of the wsdl

   

8. Create one more message element for addition response by clicking “+” symbol
   

   

   create the part by right clicking on “addOutputMsg” element.

   
   

   Specify the Part Name and Reference Value

   

9. Repeat Step “e” for creating the other message required for remaining operations
   

   
   

10. Create a “PortTypes” by clicking “+” in PortTypes section
    

    
    

    create the operation as below
    

    
    

11. specify the required details as shown below
    

    
    

    
    

12. Similarly create other operations(Subtraction, Multiplication, division)
    
13. At the end, wsdl file should look the as below
    

    
    

    3. Create a BPEL Process based on WSDL
    

    
    

    
    

    Click OK
    

    1. By default when the process is created it will create the Receive, Reply activity based on the operation type in wsdl
       
    2. Delete the default activities created as part of the process like receive, reply
       
    3. Drag and drop the pick activity on to the Calculator process
       

       Double click the pick activity and Specify the name and Select “Create Instance” checkbox

       
       

    4. Double click the OnMessage –> Select Partner Link, Operation, variable to hold the data.
       

       

       Click OK
       

    5. Drag and drop the Reply activity on to the OnMessage. Know connect the reply activity with the Partner link.
       
    6. Drag and drop the assign activity before the reply activity to assign the result value to the reply output variable.
       
    7. Add 3 more OnMessage activities as part of the Pick activity
       
    8. Repeat steps d, e, f for other OnMessage activities with other operations
       
    9. Finally your BPEL process should look like below
       

       
       

    10. Testing
        

        Login to the “EM” –> select the project –> click Test