[Ojts-develop] Added an OnVistaHTMLDataInputHandler to import share and funds data

[Christian S. <Chr...@gm...>]

i've added a data import handler to retrieve data from 
http://www.onvista.de/.

with onvista you cannot choose the stock exchange from which you want 
the data (for this purpose i added the MarketPlace called "UNDEFINED") 
nor do you get volume information. but you can get data for funds, which 
you cannot get from yahoo.

i did not implement this yet, but you can get currency data aswell, here 
for example the EUR/USD values:
http://waehrungen.onvista.de/kursliste.html?ID_CURRENCY_FROM=EUR&ID_CURRENCY_TO=USD&RANGE=3M

it would be nice if i could get historical values for certificates, too. 
but currently onvista does not provide that :(

while i was implementing the new data input handler i rewrote the 
caching subsystem from scratch. now the cached data looks the same no 
matter from which data input handler it is coming from. it is simply a 
dedicated java object structure serialized to xml. because of this 
change the import procedure now looks the same for any cached data, too!

when i have an inheritance hierarchy like the hierarchy for subject:
             subject
            /    |    \
marketplace observer securitypaper
                        /   \
                      fund share
and i want to retrieve an object from the database via castor as one of 
its base classes then i have the problem that the object is "truncated", 
that is the object is really of the baseclass type and none of its 
additional properties are available. i solved this problem now by adding 
a typeid property to the subject class and by adding a new method:
         subject = Functionality.downcastSubject(subject);
via this additional call you ensure that the returned subject is the 
correct java type with all of its additional properties available.

my next implementation plans are to
- implement currencies
  - db structures
  - retrieval of values from onvista
  - conversion of values for security papers to and from given currencies
- restructure the Functionality "namespace" class.
  - only methods with proper java types, no methods that only take strings
  - methods should always handle exceptions by throwing exceptions not 
by returning special return values
  - move the current methods that were meant to facilitate the 
integration of the functionality into sisc to another "namespace" class 
called Scheme or similar.
- finish the implementation of portfolios and its evaluation methods.

-- 
Christian Schuhegger
http://www.el-chef.de/