arguments.add(inputfile);
arguments.add(new StringArgument(this, "watermark",
"The text that can be used as watermark"));
arguments.add(new IntegerArgument(this, "fontsize",
"The fontsize of the watermark text"));
arguments.add(new FloatArgument(this, "opacity",
"The opacity of the watermark text"));
destfile = new FileArgument(this, "destfile",
"The file to which the watermarked PDF has to be written",
true, new PdfFilter());
arguments.add(destfile);