Create Custom Xpath function in BPEL - SOA 11g

Sometimes the functions available in BPEL/XSL will not be sufficient enough to handle our requirements. I came across one such scenario to find out the offset value based on date. So i created a function in java and used it as a custom xpath function in XSL.

You can use the below steps to create a function and bring it to SOA server,

1. Create a Java code.

While creating java code we need to take care of few things,

• A public static method with the same name as the function name. This method is used by the XSL function for invocation. In this example getTimeZone(String dt)
• A public Class - which will be used in custom xpath xml in next step
• A public static inner class which implements:
• oracle.fabric.common.xml.xpath.IXPathFunction
• In this example, GetTimeZoneFunction - it can be anything relevant
• We have to import  oracle.soa.fabric jar into our library, mostly it will be in below installed location. jdeveloper\soa\modules\oracle.soa.fabric_11.1.1\oracle.soa.fabric.jar

Below is the screen shot of my implemented function. I have used "joda-time-2.8.1.jar" as external library.



2. After that, we need to add this method to our custom Xpath function list. Go to below location 
Oracle/Middleware/Oracle_SOA1/soa/modules/oracle.soa.ext_11.1.1/classes/META-INF/

And edit the ext-soa-xpath-functions-config.xml

Please add the content at the bottom,

<function name="tim:getTimeZone">

    <className>sample.CustomXpathFunction</className>

    <return type="string"/>

    <params>

      <param name="date" type="string"/>

    </params>

  </function> 

also add the namespace on 1st line of the file,
<!--usually the namespace will be the combination of xmlns:tim="http://www.oracle.com/XSL/Transform/java/Package.ClassName-->
Example:

<soa-xpath-functions xmlns="http://xmlns.oracle.com/soa/config/xpath"              xmlns:aia="http://www.oracle.com/XSL/Transform/java/oracle.apps.aia.core.xpath.AIAFunctions"

 xmlns:tim="http://www.oracle.com/XSL/Transform/java/sample.CustomXpathFunction">

Now you have two options.

1a. Once the Java code is ready, generate the class files and copy(as the same folder structure) it to below location in the server,
Oracle/Middleware/Oracle_SOA1/soa/modules/oracle.soa.ext_11.1.1/classes/

or 

2a. Once the Java code is done, Create a jar file out of it and copy it to below location in your server,
Oracle/Middleware/Oracle_SOA1/soa/modules/oracle.soa.ext_11.1.1/classes/

2b. Now Run the Build.xml using ant script(How to Run ant script) in below location /omr/soa/Oracle/Middleware/Oracle_SOA1/soa/modules/oracle.soa.ext_11.1.1/






2c. Restart the SOA server 


Now you can use the function in any XSL or BPEL by defining the namespace(which we used it in ***-config.xml) in it.



Reference:
http://docs.oracle.com/cd/E23943_01/doc.1111/e17364/customxpath.htm#FPDEV2188