[Composite Datasource]: Run & Deploy your own Java Script as extensions

[kaixuan]

To allow JavaScript to be executed as extensions during the start-up process, all you need to do is add a .js file to the /ext directory and it will be processed during startup. This is intended for the once-per-session configuration of the environment.

As an example, I’ve written an example that will allow user-defined functions in the Cube and Report processing.

Here’s the JavaScript:

function JonFn()
{
  var self = new UserDefinedFunction("Jon's Average");
  self.m_Value = 0;
  self.m_Count = 0;
  self.clone = function()
	  {
	  return new JonFn();
	  }
  self.update = function(data)
	  {
	  if (data!=null)
		  {
		  this.m_Value = this.m_Value + data.doubleValue();
		  ++this.m_Count;
		  }
	  }
  self.getResult = function()
	  {
	  return this.m_Value / this.m_Count;
	  }
  self.reset = function()
	  {
	  this.m_Value = 0;
	  this.m_Count = 0;
	  }
  return new JavaAdapter(Packages.com.elixirtech.data2["function"].Function, self);
}
importClass(Packages.com.elixirtech.data2["function"].FunctionFactory);
FunctionFactory.addUserFunction(new JonFn());

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If you put this code in /ext you will find a new Function available at the bottom of the Functions list (all user-defined ones are at the bottom) called “Jon’s Average”. It produces exactly the same results as the built-in Average function.

The requirements for your Function implementation are that it provides the following methods:

clone()
update(data) // usually a Number, will be called once for each data item
getResult()
reset()

It can have whatever data it needs, in my example m_Value, m_Count - just use whatever names you want - no need to predefine.

If your function returns a different type from the input type, you will also need to supply:

getResultType(dataType)

which should return the DataType of the result, based on the DataType of the input. I’ve configured the default to be the same type (eg. Min on Int will return an Int, Min on Date will return a Date etc.)

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