Clinton, thanks for the reply. I've completed the type handler
implementation. For me, the type handler is specific to one class,
which happens to be an enum. For better encapsulation, I made the type
handler a static class inside the enum class file. Everything works fine.
But that got me to thinking: in this particular case there is a
one-to-one correspondence between type handler and the class that it
handles, so automatically associating the handler to the class would be
a convenience to the programmer. At first I was thinking of some
introspection looking for a particular class name, but on second thought
an @TypeHandler annotation would probably be more general.
Have you already thought of something like this and decided the pain
wasn't worth the gain?
Clinton Begin wrote:
No, that's actually correct. If you specify the JDBC type in the type
handler, then you have to specify it in the result map. However, if you
don't specify the JDBC type in either, that should work too, but will
override ALL string types (for example).
The reason is that iBATIS doesn't introspect the column type at runtime.
Clinton
On Tue, Sep 22, 2009 at 4:10 PM, Guy Rouillier <guyr-...@burntmail.com
<mailto:guyr-...@burntmail.com>> wrote:
I'm new to iBatis and writing my first type handler to map a
database column to an enum whose underlying type is integer. I've
got it working after falling prey to some Java limitations (can't
extend enum, can't define static methods in interfaces, the
combination of which seems to prevent me from writing a generalized
type handler for all integer-based enums.)
However, I'm a little confused as to how type handlers get mapped.
Here is my entry in the iBatisConfig.xml file (shortened for
readability):
<typeHandlers>
<typeHandler javaType="OrderStatusEnum" jdbcType="VARCHAR"
handler="OrderStatusEnumTypeHandler"/>
</typeHandlers>
Through trial and error, I discovered that in order to have iBatis
apply this type handler, in the resultMap result entry I had to
specify both javaType and jdbcType. If I supplied only javaType,
then iBatis applied the default enumTypeHandler (unsuccessfully).
I then found that if I supply typeHandler on the result entry in the
resultMap, I can dispense with the typeHandler declaration in
iBatisConfig, and also dispense with javaType and jdbcType in the
result entry. That's less typing and accomplishes the same thing.
Am I missing something? (Likely).
Thanks.
--
Guy Rouillier
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