CODEWITHSUNDEEP
javagenericsarraylist
darksky
darksky

Reputation: 21019

Generics & Types

I am using generics in a certain data structure. I have to store int x, int y, and Value value, where value is the generic type.

I am trying to group all those in one object called NodeData and then in another class, create an ArrayList of NodeData's, (so each element in the array list will include hold an x, y and value.

My NodeData is as follows:

public class NodeData<Value> {

    private int x;
    private int y;
    private Value value;

In another class, the array list instantiated as follows: ArrayList<NodeData> items = new ArrayList<NodeData>();.

I am getting an error for the array list which says: NodeData is a raw type. References to NodeData<Value> should be parametrized. Why is that? NodeData is already parametrized as NodeData<Value>.

Thanks

Upvotes: 1

Views: 124

Answers (2)

Bala R
Bala R

Reputation: 108957

In the other class, You'll have to specify the type you intend to use in place of the generic type Value

eg. 

ArrayList<NodeData<String>> items = new ArrayList<NodeData<String>>();.

Upvotes: 2

duffymo
duffymo

Reputation: 308763

Not in your array declaration. Try it like this: 

List<NodeData<Foo>> list = new ArrayList<NodeData<Foo>>();

where Foo is the Value type you want for that instance.

Upvotes: 4

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