Prototyping an interface in RPG

I'm trying to figure out how to handle a java interface type object in RPG.
The example I'm trying to replicate in RPG is using iText and the
TextExtractionStrategy interface. How do I define an object to have the
TextExtractionStrategy object type. When I read the javadoc, it doesn't
give me any clues to what to set the class to or even if there is a
constructor to specify.

Here is the java code example that I'm trying to somewhat do within RPG. I
get stuck trying to figure out how to define the "strategy" object. This
code snippet is supposed to extract text within a given area of a PDF and
is taken from the iText website:

PdfReader reader = new PdfReader(pdf);
PrintWriter out = new PrintWriter(new FileOutputStream(txt));
Rectangle rect = new Rectangle(70, 80, 420, 500);
RenderFilter filter = new RegionTextRenderFilter(rect);
TextExtractionStrategy strategy;
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
strategy = new FilteredTextRenderListener(
new LocationTextExtractionStrategy(), filter);
out.println(PdfTextExtractor
.getTextFromPage(reader, i, strategy));
}
out.flush();out.close();