Usage of the IF Construct

Objective

This sample illustrates the usage of the <if/> construct in verifying a logical condition.

Introducing the IF Construct

<if>
   <condition>number($tmpVar)=number(2)</condition> 
      <assign name="assignError"> 
        <copy> 
           <from> 
              <literal>Worked</literal> 
           </from> 
           <to variable="myVar" part="TestPart"/> 
        </copy> 
      </assign> 
   <else> 
      <assign name="assignZut"> 
        <copy> 
           <from> 
              <literal>Failed</literal> 
           </from> 
           <to variable="myVar" part="TestPart"/> 
        </copy> 
      </assign> 
   </else> 
</if>

The <condition/> element inside <if/> is used to implement the logical condition. Normally, an XPath expression is used. <else/> is used to implement false case. In the above example, value of tmpVar variable is converted to a number and checked against number 2 as follows:

<condition>number($tmpVar)=number(2)</condition>

Based on the tmpVar value, "TestPart" element value in myVar variable will be "Worked" or "Failed".

Deploying the Sample

WSO2 BPS provides a sample, which can be deployed and executed to understand the IF constructs discussed above. Follow the instructions below to deploy and trigger the process.

1. Log in into BPS server management console and select "Processes -> Add" under the "Main" menu.

2. Upload the TestIf.zip. (Samples are located at our sample repository).

3. In the "Deployed Processes" window, click the "Process ID" to access its "Process Information" window.

4. Under the "WSDL Details" widget, trigger the process using the "TryIt" link to create an instance of it.