Does java contain a data type named "Item"?

Question

I'm reading the book Algorithms and they mentioned a data type Item. However, I can't find it in any of the API. Does "Item" data type exist in java?

Answer 1

On page 124, Sedgwick writes

"The name Item is a type paramter, a symbolic placeholder for some concrete type to be used by the client."

public class FixedCapacityStack<Item>

It's just a Generic Type:

http://docs.oracle.com/javase/tutorial/java/generics/types.html

public class Box<T> {
    private T t;

    public void set(T t) { this.t = t; }
    public T get() { return t; }
}

Sedgwick uses "Item" instead of "T" because a Stack of "Item" was easier to read than a Stack of "T". The point is you can put anything in there, although according to the Java documentation you should follow a naming convention:

E - Element (used extensively by the Java Collections Framework) K - Key N - Number T - Type V - Value S,U,V etc. - 2nd, 3rd, 4th types

which clearly he decided not to!

Answer 2

No, there's no Item in the JDK 6 javadocs. That must be a custom class that Sedgewich wrote. Maybe you mean the ITEM interface on page 272 of the 4th edition:

http://books.google.com/books?id=hyvdUQUmf2UC&pg=PA272&lpg=PA272&dq=sedgewick+Item+class&source=bl&ots=kASI71PjAc&sig=BACGl1Q9nj43vhPwG8RVtO7euwI&hl=en&sa=X&ei=DnYIT42GDqTX0QGthpSTAg&ved=0CCAQ6AEwAA#v=onepage&q&f=false