| Object within an Object's Structure [message #71281] |
Wed, 09 June 2010 12:12  |
carl
Messages: 3
Registered: June 2010
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Junior Member |
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Hello,
I am trying to make use of what OOP functionality IDL has, and I wish
to have as an object variable another object of a different type.
Is this possible? If so, how do I specify this?
I have an object type orbitingBody, and want to make an object
orbitingPair. Would this work? how would it be then coded in my init
function?
pro orbitingpair__define
struct = { orbitingPair,
planet: obj_new('orbitingbody', args)
star: obj_new('orbitingbody', args)
etc...}
end
thanks,
Carl
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| Re: Object within an Object's Structure [message #71366 is a reply to message #71281] |
Thu, 10 June 2010 15:22  |
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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Paul van Delst wrote:
>
> carl wrote:
>> Hello,
>>
>> I am trying to make use of what OOP functionality IDL has, and I wish
>> to have as an object variable another object of a different type.
>>
>> Is this possible? If so, how do I specify this?
>>
>> I have an object type orbitingBody, and want to make an object
>> orbitingPair. Would this work? how would it be then coded in my init
>> function?
>>
>> pro orbitingpair__define
>> struct = { orbitingPair,
>> planet: obj_new('orbitingbody', args)
>> star: obj_new('orbitingbody', args)
>> etc...}
>> end
>
> Hmm. Why restrict yourself to only planetary and star orbiting bodies? (e.g. asteroids?
> comets?) Or even just two?
>
> Assuming your "orbitingbody" object definition contains property information about the
> type of orbiting body (i.e. planet, star, moon, asteroid, comet, etc), why not something like:
>
> pro orbitingSet__define
> void = { orbitingSet,
> n_bodies = 0L, $
> ; Container for orbiting bodies
> INHERITS IDL_Container }
> end
>
> ?
>
> You can then add as many orbiting bodies as you like:
>
> pro orbitingSet::Add, $
> obj, $ ; Object to add
> _REF_EXTRA = Extra ; Keywords passed onto IDL_Container::Add
>
> ; Add object to the container
> self->IDL_Container::Add, obj, _EXTRA = Extra
>
> ; If the object added is an orbitingBody object, increment the counter
> IF ( OBJ_ISA(obj, 'orbitingBody') ) THEN self.n_bodies++
> end
>
> This way you can store more information in your "orbitingSet" container if the need ever
> arises... and the objects you add needn't be just orbitingBody objects either.
I forgot to add a proposed get function
function orbitingSet::Get, $
_REF_EXTRA = Extra ; Keywords passed onto IDL_Container::Get
; Get the requested object reference
objref = self->IDL_Container::Get(_EXTRA = Extra)
RETURN, objref
end
(I can't recall if the _REF_EXTRA keyword just needs to be an _EXTRA or not....)
Via the IDL_Container::Get keywords, for an orbitingSet object (let's call it oSet), you
can do things like:
obj = oSet->Get(ISA='orbitingBody', COUNT=n)
if ( n EQ 0 ) then $
message, 'No orbiting bodies in set!'
You can then fancy the internals up a bit so you can return particular types of orbiting
bodies too.
Anyway....
cheers,
paulv
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| Re: Object within an Object's Structure [message #71367 is a reply to message #71281] |
Thu, 10 June 2010 15:00 |
Paul Van Delst[1]
Messages: 1157
Registered: April 2002
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Senior Member |
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carl wrote:
> Hello,
>
> I am trying to make use of what OOP functionality IDL has, and I wish
> to have as an object variable another object of a different type.
>
> Is this possible? If so, how do I specify this?
>
> I have an object type orbitingBody, and want to make an object
> orbitingPair. Would this work? how would it be then coded in my init
> function?
>
> pro orbitingpair__define
> struct = { orbitingPair,
> planet: obj_new('orbitingbody', args)
> star: obj_new('orbitingbody', args)
> etc...}
> end
Hmm. Why restrict yourself to only planetary and star orbiting bodies? (e.g. asteroids?
comets?) Or even just two?
Assuming your "orbitingbody" object definition contains property information about the
type of orbiting body (i.e. planet, star, moon, asteroid, comet, etc), why not something like:
pro orbitingSet__define
void = { orbitingSet,
n_bodies = 0L, $
; Container for orbiting bodies
INHERITS IDL_Container }
end
?
You can then add as many orbiting bodies as you like:
pro orbitingSet::Add, $
obj, $ ; Object to add
_REF_EXTRA = Extra ; Keywords passed onto IDL_Container::Add
; Add object to the container
self->IDL_Container::Add, obj, _EXTRA = Extra
; If the object added is an orbitingBody object, increment the counter
IF ( OBJ_ISA(obj, 'orbitingBody') ) THEN self.n_bodies++
end
This way you can store more information in your "orbitingSet" container if the need ever
arises... and the objects you add needn't be just orbitingBody objects either.
cheers,
paulv
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