I apologies to all of you and especially to Gopi Nandamuri
for the mail i posted a few days ago on this mailing list.
My intention was not to offend Gopi and in fact i
completely misunderstood his questions. In the future,
i will pay close attention, before replying to a mail,
to be sure to have really understood the meaning and to
be able to give something consistent as a reply.
As a good will and amendment gesture i want to propose the following
code of a PersistentField that i wrote to solve a problem i had
with nested fields. I think that the problem is not restrained to me.
The problem arise when using nested objects that can be nulled.
Actually, when ojb reads the first field of a nested object that is
null, an instance is created to continue the recursive walk through
the nested objects, even if the given value to set for the attribute
is null. So i needed to make two modifications for the process to work.
* first i had overriden the 'set' method of the AbstractPersistentField
class to early test if the value will not be set. The added test is
borrowed from the PersistentFieldDirectAccessImpl but is performed
before having created an instance of the nested object.
public void set(Object targetObject, Object value) throws
MetadataException
{
if (isNestedField())
{
if (value != null || !getField().getType().isPrimitive())
{
setNestedObject(targetObject, fieldName, value);
}
}
else
{
doSet(targetObject, value);
}
}
* the second modification i did is needed because the test on the 'set'
method
works only for primitive types. But if we store a Date for example in a
nested
object, it will be nevertheless created. But the test can not extend
the test
made earlier, because if we nested objects could have non-null default
values
for certain fields. So i overrided the 'setNestedObject' method to
perform
the test so that when realizing that the nested object is null, there
is no need
to create one to put a null value in the field.
When the added test 'if (attrib != null || value != null)' is true
the instanciation and setting of the attribute is skipped.
protected void setNestedObject(Object obj, String fieldName, Object
value)
{
int index = fieldName.indexOf(PATH_TOKEN);
if (index >= 0)
{
String name = fieldName.substring(0, index);
PersistentField pField =
createInternPersistentField(ProxyHelper.getRealClass(obj), name);
Object attrib = pField.get(ProxyHelper.getRealObject(obj));
if (attrib != null || value != null)
{
if (attrib == null)
{
.......
}
String nestedName = fieldName.substring(index +
PATH_TOKEN.length());
setNestedObject(attrib, nestedName, value);
}
}
else
{
PersistentField pField =
createInternPersistentField(ProxyHelper.getRealClass(obj), fieldName);
pField.set(ProxyHelper.getRealObject(obj), value);
}
}
Best regards,
Guillaume Nodet
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