Vectors with multiple types of objects

Question

Ok, this is what i need. I have a main class, EquationVector, and i have four smaller classes, MathPrimitive, which is abstract and all of the following classes extend, Number which just holds numbers, Operator which takes care of what type it is and what to do, and Variable, which knows its value, its coef and its power. I use the MathPrimitive class because all of the other classes need to have a common getType() method, plus it holds static values for all the possible types. What i need is some sort of storage method that is dynamically resizeable, and can handle multiple types of objects. I tried vector, but it doesnt work, even when i cast. I want to be able to do something to the effect of
myArray.elementAt(index).getOperatorType()
and be able to get the operator type if its an operator, but at the same time be able to do
myArray.elementAt(index).getCoef()
and be able to get the coeficient if its a variable. I'm not sure if this is actually possible, so if anybody has any good ideas i would be really apreciative. Thank you.

Answer 1

Vector will absolutely work, as will ArrayList
You just better make sure you know what kind of objects are at what slots in the vector.
opType = ((MathPrimitive) myArray.elementAt(index)).getOperatorType();
If you don't know what type of object is at a particular slot you can always use
Object o = myArray.elementAt(index);
if (o instanceof MathPrimitive)
else
....