Calling Java Code from OScript (1)

Sometimes it would be nice to use existing Java coding from a module instead of recoding this in OScript.

There is a facility in the content server which does exactly this bridging from OScript to Java, the so called JavaObject class. You’ll find the exact documentation in the “OScript API/Build-In Package Index”

In this first post of the series we’ll discuss the  basic calls from OScript.

First, you need some Java Code, compiled and in the form of a jar. Put this jar either in OTHOME/ojlib or (much better) in a ojlib directory in your module structure. After installing the module, the jar(s) are copied automatically to the OTHOME/ojlib. Then, the jvm classloader will find your jar(s).

From OScript it is possible to access static classes and instances.

Dynamic InvokeStaticMethod(String classname, String methodName, List parameters)

Dynamic GetStaticField( String classname, String fieldName)

Dynamic SetStaticField( String className, String  fieldName, Dynamic value)

The return values are either Error or Dynamic if the call is successful.

JavaObject New (String className, List parameters)
Dynamic GetField(String fieldname)

Dynamic SetField(String fieldname, Dynamic value)

Dynamic InvokeMethod(String methodName, List parameter)

The return values are either Error or Dynamic if the call is successful.

An example
function void javaTest()

   JavaObject myObject

   myObject ="my.own.package.class")
   Dynamic res = myObject.InvokeMethod("myMethod",{"aa","bb})

   if (isError(res))

     echo ("Init failed")



   Dynamic res1 = myObject.GetField("myResult")

   if (IsError(res)) 

     echo("Calculation failed")



   echo("The result is "+res1)


In the next post we’ll discuss how to get the JNI exceptions and the error stack from the jvm.