On 10.09.2006 08:13, email@example.com wrote:
Compared to the overhead you pay for the list and the objects that make
up your values the overhead of an additional object that encapsulates
values and counts seems negligible. This smells a bit like premature
May be. I did not yet do any real memory consumption test. I probably
will do really soon. But until then I think, every object counts - at
least for objects in the global cache (that will go into old-gen) and
for numbers of objects growing with the size of the cache.
Btw, did you also consider using a LRU cache? It's pretty easy to
implement and has little run time overhead.
Just out of curiosity: what features does your persistence framework
provide that existing frameworks do not?
I really like static type safety. [snip]
I think this is dealt with by existing implementations of OOR mappings.
Second I don't like writing XML (or any other external, non-java)
description of the persistent schema. Within COPE (did I mention the
name of the framework already :-) ), everything is specified within
your Java source code. Everything. Persistent classes, fields,
EJB 3.0 and Hibernate can also use Java 1.5 annotations.
And I want support for migrating the database to new versions of the
application without loss of data. For instance, if you add a new
persistent field to the schema you must not forget to add a new column
to the database table. For COPE there is a helper application telling
you which column (or table or constraint) is missing (or not used any
longer) and lets you create (drop) it with a single click. I really
missed this in my projects, because it's another typical source of that
"column not found"-SQLExceptions.
I'm not sure what EJB and Hibernate do about this but since this is such
a common scenario I bet they have solved this already.
And I don't want to waste my time remembering, which column type can
store a string up to 400 characters most efficiently with that
particular database I'm using right now. Was it "varchar(400)" or
"varchar2(400)" or "text" or "tinytext" or just "string" ? Grmpf. COPE
does that for you.
Again, EJB and Hibernate deal with that, too. There is also db4o which
also has nice querying features IIRC: http://www.db4o.com/
Ooops. Got a bit lengthy :-) .
And of course the cache will be the most effifcient on earth when it's
ready, but it's not yet. :-)
Certainly. :-) Sorry if I'm sounding discouraging but I have yet to see
the feature that makes your work stand out against existing solutions.
There is also a website, with some explanation:
Thanks for that link!
Pretty reliable and a lot of groups but comes with a small cost. I was
annoyed with trouble I had with free newsservers so I switched over.
Thanks a lot. I just registered.
No sweat. Have fun!