Re: Java/OO techniques for modularity and re-use

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <>
Sat, 30 Jun 2007 19:46:03 -0400
Richard Maher wrote:

I have created a class that uses the class to talk to my
server and everything is great. I then converted the code to use the class and (thanks to how easy Java makes it for us!)
everything is still great. What I want to do now is parameterize/optionalize
the use of SSL or in-the-clear Sockets within my class, and I'm struggling
to find a modular, let alone elegant, solution.

At the moment I plan to add another Applet parameter called SSL_REQD and I
will pass that to my constructor, but because of Java's compile-time
resolution of methods-to-objects, I find myself having to duplicate code
that is erstwhile 99% identical or common. Is there some way (short of
Reflection) that I can leverage the fact SSLSocket class inherits most of
its methods from the Socket class so that I only need one method for each
socket function regardless of what flavour socket is in use?

For example: -

private someSocket t3Sock;

if (sssReqd)
  t3Sock = (SSLSocket)sockFactory.createSocket();
  t3Sock = new Socket();


Am I stuck with "One's an Apple and the other's an Orange (albeit painted
red :-)"?

If few of the Socket methods are overridden by SSLSocket (and the
value-added encryption stuff happens at a lower/other level) can I just cast
my way around some of this? Just stick in a few "if" statements and stop

Since SSLSocket inherits from Socket then you can make your
t3sock of type Socket (you can assign from a subtype to a
super type).

If you need to use a SSL specific funtion you can use:

But that is not "nice".

I would find it tempting to create a wrapper class hirachy:
CommonSocketWrapper, SocketWrapper and SSLSocketWrapper where
SocketWrapper has some do nothing methods for the SSL specific

If that is not what you are looking for, then pleas explain.


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