Hello, I've just been banging my head
over how to calculate Williams Perfect Range (WILLR):

private IBar[][] inputs = new IBar[1][];

wpr = new Object[endIndex - startIndex + 2 + iWPR.getLookback()];
iWPR.setInputParameter(0, inputs[0]);
iWPR.setOptInputParameter(0, periods);
iWPR.setOutputParameter(0, wpr);
IndicatorResult wprResult = iWPR.calculate(startIndex, endIndex);

When I try to run it, I get the error:
2011-06-26 21:11:57 Error in indicator: java.lang.ClassCastException: [Lcom.dukascopy.charts.data.datacache.l; cannot be cast to [[D @ JemmyWPR.calculate(JemmyWPR.java:76)

There is no source code and documentation, which gives me a hint how
to use the indicator properly.
I even tried to decompile some of the jforex classes, in order to understand
how to use that class with no notable success so far.

Unfortunately the indicator is not included in the sources file.
Please help!

Try changing the input type as follows:

  private double[][][] inputs = new double[1][][];
  ...
  inputParameterInfos = new InputParameterInfo[] {new InputParameterInfo("Input", InputParameterInfo.Type.PRICE)};
  ...
  iWPR.setInputParameter(0, inputs[0]);
  ...