Touring Language APIs - Beginning Java 7 - page 356

case HEX:
System.out.println("outputting EXE content in
hexadecimal");
}

}

}

ViewerEXE 's view() method demonstrates using the switch statement to switch
onanenumconstant.Forbrevity,I'velimitedthismethodtoprintingmessagestostand-
ardoutput.Also,Idon'tpresentthecorresponding ViewPNG class,whichhasasimilar
structure.
Listing4-13 presentsanapplicationthatdynamicallyloads ViewerEXE or View-
erPNG ,instantiatestheloadedclassvia newInstance() ,andinvokesthe view()
method.

Listing 4-13. Loading, instantiating, and using Viewer subclasses

class ViewerDemo
{

public static void main(String[] args)
{

if (args.length != 1)
{

System.err.println("usage : java ViewerDemo

filetype");
System.err.println("example:

java ViewerDemo

EXE");

return;

}
try
{

Class<?> clazz = Class.forName("Viewer"+args[0]);
Viewer viewer = (Viewer) clazz.newInstance();
viewer.view(null, Viewer.ViewMode.HEX);

}
catch (ClassNotFoundException cnfe)
{