The typical pattern for one-to-many is this:
Code:
class ParentObject {
private Set children = new HashSet();
public Set getChildren() { return this.children; }
public void setChildren(Set children) { this.children = children; }
public void addChild(ChildObject child) {
child.setParent(this); // child has a many-to-one to parent
this.children.add(child);
}
}
I assume this is what you mean by a "trivially simple case". It's not significantly more work to handle many-to-many relationships, which are the most complex association type that I'm aware of.
It's not clear to me what your relationships look like, so it's hard to take a swing at the problem.