Clean Code

String Arguments
Now we can get rid of some crufty functions in 
IntegerArgumentMarshaler
and clean it up
a bit.
private class IntegerArgumentMarshaler extends ArgumentMarshaler {
private int intValue = 0
public void set(Iterator currentArgument) throws ArgsException {
String parameter = null;
try {
parameter = currentArgument.next();
intValue = Integer.parseInt
(parameter);
} catch (NoSuchElementException e) {
errorCode = ErrorCode.MISSING_INTEGER;
throw new ArgsException();
} catch (
NumberFormatException
e) {
errorParameter = parameter;
errorCode = ErrorCode.INVALID_INTEGER;
throw new ArgsException();
}
}
public Object get() {
return intValue;
}
}
We can also turn 
ArgumentMarshaler
into an interface. 
private
interface
ArgumentMarshaler {
void set(Iterator currentArgument) throws ArgsException;
Object get();
}
So now let’s see how easy it is to add a new argument type to our structure. It should
require very few changes, and those changes should be isolated. First, we begin by adding
a new test case to check that the 
double
argument works correctly.
public void testSimpleDoublePresent() throws Exception {
Args args = new Args("x##", new String[] {"-x","42.3"});
assertTrue(args.isValid());
assertEquals(1, args.cardinality());
assertTrue(args.has('x'));
assertEquals(42.3, args.getDouble('x'), .001);
}
Now we clean up the schema parsing code and add the 
##
detection for the 
double
argument type.
private void parseSchemaElement(String element) throws ParseException {
char elementId = element.charAt(0);
String elementTail = element.substring(1);
validateSchemaElementId(elementId);
if (elementTail.