Q: Accessing lower level classes

Question

I'm having trouble even phrasing this question, so please bear with me.
I have several classes in a hierarchy (5 levels deep). All have empty constructors and each has an addXXXX method to populate the required internal attributes. The addXXXX methods have very loooooong parameter lists.
I can't say that Class A extends Class B, because Class A actually references multiple Class Bs. Think of Class A like a table and Class B as the records in the table.
I guess what I'm asking is should class b have it's addXXXX defined with it's long parameter list and then in Class A have another method addClassBAttrs with a really long parameter list that does nothing but call array[i] = ClassB() and then array.addXXXX( really long param list)?
Does that make sense? I know that will work but it doesn't seem very OO (I'm not a new programmer, 15 years. I am new to Java and OO).
Just FYI, an example of my class hierarchy might look something like:
Class A
- Class B
-- Class D
-- Class C
--- Class D
-- Class C
--- Class D
--- Class D
- Class B
-- Class D
-- Class C
- Class B
- Class E
The rules are Class A is always Unique, always exists and only appears at level 1.
Class E always is optional, is unique if it exists and can only appear at level 2.
At least 1 Class B will always appear and will only appear at level 2.
At least 1 Class C will appear for each class B and will only appear at level 3.
Class D is optional and can appear at level 3, after a Class B or at level 4 after a Class C.
I just reread this and I hold out slim hopes for anyone making head or tails from it but I have to try.
I've searched tutorials and white papers but can't find anything that addresses this particular layout.
Thanks,
Lewis

Answer 1

Let's take a fictitional set of classes:
class C1 {
    int c1a;
    int c1b;
    int c1c;
    public C1( int c1a, int c1b, int c1c, ... ) {
        setC1a( c1a );
        setC1b( c1b );
        setC1c( c1c );
    public void setC1a( int c1a ) {this.c1a = c1a }
    ... other methods to set attributes
    public int getC1a() {return c1a};
    ... other accessor methods
class CN {
    code like C1 except all variables are cN, where N is some number
class B1 {
    C1 c1;
    C2 c2;
    public B1( C1 c1, C2 c2, ... ) {Code to set attributes}
    public void setC1( C1 c1 ) {this.c1 = c1}
    ... and so on
class BN {
    code like B1 except all variables are bN, where N is some number
and finally our A class
class A{
    B1 b1;
    b2 b2;
    public A( B1 b1, B2 b2, ... ) {Code to set attributes}
    public void setB1( B1 b1 ) {this.b1 = b1}
    ... and so on
}Note that you can create an instance of A by doing...
A a = new A(
    new B1(
        new C1( 0, 0, 0, ... ),
        new C2( 0, 0, 0, ... ),
    new B2( ... ),
    ...  )or you can do create one by doing
C1 c1 = new C1( 0, 0, 0, ... );
C2 c2 = new C2( 0, 0, 0, ... );
B1 b1 = new B1( c1, c2, ... )
B2 b2 = new B2( ... );
A a = new A( B1, B2, ... );