multi-inheritance between EntityBeans

[Grzegorz Trafny]

Hi,

Question is lightly theoretical but how to implement project
(for example: data model ) in which was used multi-inheritance?
Especially, how to model multi-inheritance in apps which data
is based on EntityBeans?

Problem is quite large because normally it is not possible to apply
(in EntityBeans) even single inheritance. However it exists patterns
to solve this problem (f.e.: article "EJB Inheritance" from onjava.com).
Maybe someone know way (similar to above mentioned) how to
by-pass problem of multi inheritance in EntityBeans (and java ))?

Greetings
GT

 

[Hal Rosser]

Hi,

Question is lightly theoretical but how to implement project
(for example: data model ) in which was used multi-inheritance?
Especially, how to model multi-inheritance in apps which data
is based on EntityBeans?

Problem is quite large because normally it is not possible to apply
(in EntityBeans) even single inheritance. However it exists patterns
to solve this problem (f.e.: article "EJB Inheritance" from onjava.com).
Maybe someone know way (similar to above mentioned) how to
by-pass problem of multi inheritance in EntityBeans (and java ))?

Greetings
GT

you can try (drum roll)
implementing multiple interfaces

 

[Grzegorz Trafny]

Question is lightly theoretical but how to implement project
(for example: data model ) in which was used multi-inheritance?
Especially, how to model multi-inheritance in apps which data
is based on EntityBeans?

[cut]

you can try (drum roll)
implementing multiple interfaces

Not exactly, I meant situation where project directly show that
(for example) 3 entities are dependent like these:
"ClassC extends ClassA, ClassB"
and everyone class must has instance variables.

What Java programmer should do in that situation?
Is the only way out from this situation is change of
project, how better to do this?

Greetings
GT

 

[Grzegorz Trafny]

Not exactly, I meant situation where project directly show that

(for example) 3 entities are dependent like these:
"ClassC extends ClassA, ClassB"
and everyone class must has instance variables.

What Java programmer should do in that situation?
Is the only way out from this situation is change of
project, how better to do this?

Excuse me, I can't believe, nobody knows what to do?

 

[Thomas Weidenfeller]

Excuse me, I can't believe, nobody knows what to do?

Because there isn't much to do. You don't have multiple inheritance in
Java. Period. If you base your design on multiple inheritance you are
shooting yourself in the foot. Don't shoot yourself in the foot is the
best advice, change your design.

If you want to hack around it, use interfaces and a lot of bridging
code, use a code generator, or use another language.

/Thomas

 

[Andrei]

Question is lightly theoretical but how to implement project
(for example: data model ) in which was used multi-inheritance?
Especially, how to model multi-inheritance in apps which data
is based on EntityBeans?

[cut]

you can try (drum roll)
implementing multiple interfaces

Not exactly, I meant situation where project directly show that
(for example) 3 entities are dependent like these:
"ClassC extends ClassA, ClassB"
and everyone class must has instance variables.

What Java programmer should do in that situation?
Is the only way out from this situation is change of
project, how better to do this?

Greetings
GT

you could use delegates, for what is possible