Composition??

[Germyan]

That is rather a good one than the one at wiki.. but the practicality of the class red is questionable.. I think there are better ones.. G.

[Shog9 0]

I need a collection type that will store objects. It will let me iterate through the objects it contains, access them by ordinal, or retrieve a subset of them matching a given attribute. I might compose this type from an array (iteration, ordinal lookup) and a tree (attribute lookup - match a branch).

[Germyan]

It does.. That is why you have three different relations named association, aggregation and composition.. You can cover all by aggregation and composition can cover with aggregation but when you defined a composition, it is special and cannot be covered by any of the other two. Your or the one you pointed comes under aggregation not composition.. so you cannot argue any longer with your example.. :(

[Germyan]

yes, that is also a good one.. when objects are not existing you will not have the collection defined. But when you have one to many relation in between the collection and object it again comes under aggregation.. so it is also not composition.. Additional object can exist without a collection.. I think you are also wrong ... :( G.

[Ennis Ray Lynch Jr]

From the Agile Definition: Sometimes an object is made up of other objects. For example, an airplane is made up of a fuselage, wings, engines, landing gear, flaps, and so on. A delivery shipment contains one or more packages. A team consists of two or more employees. These are all examples of the concept of aggregation, which represents “is part of” relationships. An engine is part of a plane, a package is part of a shipment, and an employee is part of a team. Aggregation is a specialization of association, specifying a whole-part relationship between two objects. Composition is a stronger form of aggregation where the whole and parts have coincident lifetimes, and it is very common for the whole to manage the lifecycle of its parts. From a stylistic point of view, because aggregation and composition are both specializations of association the guidelines for associations apply. I don't see what the big deal is.

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[led mike]

Germyan wrote:

So the Carburetor and Car is a software world example??.. I don't think so..

Is the Carburetor and Car the only example on that page??.. I don't think so.. But, again I don't expect you are someone that reads technical information efficiently.

Germyan wrote:

I think that WIKI example is a poor one and your answer is also a poor one..

I think your effort is a poor one, your reply is a poor one, and it's a fair assumption you are a poor one.

led mike

[Shog9 0]

Wait - just what do you think aggregation is? And why do you think composition isn't aggregation? :suss:

[Lost User]

Germyan wrote:

but the practicality of the class red is questionable.. I think there are better ones..

you just cant please some people

[Germyan]

You can bring up definition, but as a software developer and a one who visit code-project regularly, show me a real place where you have ever used this.. I can bring you thousand of cut and paste definitions as well as physical world's examples.. but the question is something else..

Ennis Ray Lynch, Jr. wrote:

I don't see what the big deal is.

Then you stay out of this.. This is a challenge if you are ready to accept it accept, if not you can go away.. I am sorry if it is rude :rolleyes:

[Ennis Ray Lynch Jr]

Poor communication is a challenge best left to those with weak minds.

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Happiness in intelligent people is the rarest thing I know. -- Ernest Hemingway

[Germyan]

Come up with valid facts.. I like to hear you. :~ Anyway, I like, if you can stick with the OP, rather than shooting off target to cover your not knowingness. :( You don't have an answer do you?? G.

[Germyan]

Ennis Ray Lynch, Jr. wrote:

Poor communication is a challenge best left to those with weak minds.

Don't shoot off target.. If the communication is the problem I will try my best to correct it. However the OP question is a simple one.. show me a example where you really used composition in any of your system. Isn't that not clear? G.

[Germyan]

I am referring to the definitions, composition is a special type of a aggregation, so I am not telling that composition is not aggregation. But what I said was that the example you gave does not have that specialty to recognize as it is composition. G.

[Shog9 0]

Germyan wrote:

But what I said was that the example you gave does not have that specialty to recognize as it is composition.

Ok then. Please explain to me what's missing in my example.

[led mike]

I believe the section of that wikipedia page on Aggregation covers the topic very clearly and correctly. But of course you would have to read it to know that wouldn't you now?

Germyan wrote:

You don't have an answer do you??

I know I have an answer to the problem called Germyan. I won't read any more of your messages. X|

led mike

[Germyan]

Josh Gray wrote:

you just cant please some people

:confused::confused: G.

[Germyan]

you are missing a important one.. when a composition is destroyed, are the objects belonging to it be destroyed as well? If the answer is NO then it is AGGREGATION. G.

[Germyan]

:laugh: :laugh: :laugh: I am sorry, if I did something wrong here.. but I know most people don't know the concepts they play with on day to day basis. Just thought to play on it.

led mike wrote:

problem called Germyan.

:laugh: - creative one G.

[Shog9 0]

Germyan wrote:

you are missing a important one.. when a composition is destroyed, are the objects belonging to it be destroyed as well? If the answer is NO then it is AGGREGATION.

AFAIK, there's a little bit more to it than that... but i'll bite: where in the example that i gave you did i imply that any part of my composite collection type would not be destroyed along with the collection? Granted, i did not explicitly state that it wouldn't leave bits and pieces of itself orphaned and scattered all over Creation... but i didn't think it was necessary to state such an obvious requirement.

[Germyan]

I think you said that it is a objects collection.. inside the collection you will have objects, They used a famous example to explain composition.. house vs room, can the room exist without a house?? NO Can the object exist without a collection?? YES.. so your example is not composition. I mean there are many areas, where your example violate the original definition of the composition. But, I do agree that it is the closest example, I get so far. G.