UML-problem...

Question

Hello,
I have got a big UML-problem: I don't know how to code a simple association in Java. An
aggregation is very simple to realize, I just put a reference on the corresponding class,
like:
public class ClassA {
     ClassB cb = new ClassB();
public class ClassB {
Are association realized the same way ? If not can you give me a short example for a simple association ?
Thank you very much,
Findus

Answer 1

I believe what you've explained is in fact how you'd realize a simple association. Aggregation is typically realized using a collection.
Simple association:
ClassA is associated with ClassB
public class ClassA{
  ClassB cb = new ClassB();
Aggregation:
ClassA has 0 or more instances of ClassB
public class ClassA{
  //need a collection to hold 0 or more instanced of ClassB
  java.util.List cbList = new java.util.ArrayList();
}Hope this helps.