On Dec 31, 2009, at 11:24 AM, Andrey Razumovsky wrote:
1. Instead of:
Expression clause2 =
ExpressionFactory.matchExp(Artist.PAINTINGS_PROPERTY +
"." + Painting.NAME_PROPERTY, "Y");
I prefer using just
Expression clause2 =
ExpressionFactory.matchExp("paintings.paintingName",
"Y");
Yes, I don't like using constants, to me bottom example seems more
readable,
short and quicker to write (especially if there are a lot of items
in the
path). As far as I understood, this will not be allowed in new API (?)
Looks like your schema doesn't change too often :-)
Anyways, we can still allow that in the new API. And even preserve
"declarative" type-safety:
Expression clause2 = new Key<String>("paintings.paintingName").eq("Y");
2. I wrote a library which automatically builds Cayenne expressions
from
values user specified in grid filter of Web (GWT) client - path is
coming
from client. With new API, shall I have something like
CayenneDataObject.getKey(String) method to obtain any key in uniform
way?
(even with that, I will have more work to do to convert path to new
API,
maybe we need some method like Key Cayenne.getNestedKey(Class clazz,
String
path)?
See the example above (new Key<?>(...)). Capability-wise the new API
will allow everything ExpressionFactory does.
3. I have examples of intentionally not following type-safing for
expressions (these are real examples)
a. EF.matchExp("artist", "200") - quick comparison of relation
object's id
b. EF.lessExp("date", "2010-01-01 10:00:00.000") - replacement of
date (or
int, double, whatever) with just string
Will those be allowed somehow in new API?
I guess there are two ways about it.
1. new Key<Object>(..)
2. Provide methods that do String to object conversions for common
cases of dates and numbers, using explicit or implicit formatters E.g.
new Key<Date>("dob").after("2010-01-01 10:00:00.000", "YYYY-mm-
dd...");
new Key<Integer>("age").eq("200");
Among other things this will make some drivers (like PostgreSQL)
happy, as they don't allow fuzzy types in PreparedStatement bind
parameters.
Happy New Year!!!
Happy New Year to everybody :-)
Andrus
