Aggregate and composite?

[William Stacey]

Please help me understand the difference or sameness of aggregate and
composite associations. Simple example with description would be helpful.
tia

 

[Jeff Louie]

William... Can you first write down your definition of aggregate and
composite? Just accepting my answer is not going to help you learn
much.

Regards,
Jeff

Please help me understand the difference or sameness of aggregate

and composite associations. Simple example with description would be
helpful.<

 

[Jeff Louie]

This may help: Composite class, containment by ownership:

class Radio
{
...
}
class Vehicle
{
...
}
class Car : Vehicle
{
Radio r= new Radio();
}

In a composite class the lifetimes of the object and sub object are
intertwined.

vs containment by reference:

class Radio
{
...
}
class Vehicle
{
...
}
class Car : Vehicle
{
private Radio r;
public Car(Radio r) {
this.r= r;
}
}


Regards,
Jeff

 

[William Stacey]

Thanks Jeff. This link helped a lot too. Most pointed talk on containment
and aggregation I have seen.
http://www.objectmentor.com/resources/articles/umlClassDiagrams.pdf