DLLNode.java

/*****************************************************
 * class DLLNode
 * Implements a node, for use in lists and other container classes.
 *****************************************************/

public class DLLNode<T> 
{
    private T _cargo;    //cargo may only be of type T
    private DLLNode<T> _nextNode, _prevNode; //pointers to next, prev DLLNodes


    // constructor -- initializes instance vars
    public DLLNode( T value, DLLNode<T> prev, DLLNode<T> next ) {
	_cargo = value;
	_nextNode = next;
	_prevNode = prev;
    }


    //--------------v  ACCESSORS  v--------------
    public T getCargo() { return _cargo; }

    public DLLNode<T> getNext() { return _nextNode; }

    public DLLNode<T> getPrev() { return _prevNode; }
    //--------------^  ACCESSORS  ^--------------


    //--------------v  MUTATORS  v--------------
    public T setCargo( T newCargo ) {
	T car = getCargo();
	_cargo = newCargo;
	return car;
    }

    public DLLNode<T> setNext( DLLNode<T> newNext ) {
	DLLNode<T> current = getNext();
	_nextNode = newNext;
	return current;
    }

    public DLLNode<T> setPrev( DLLNode<T> newPrev ) {
	DLLNode<T> current = getPrev();
	_prevNode = newPrev;
	return current;
    }
    //--------------^  MUTATORS  ^--------------


    // override inherited toString
    public String toString() { return _cargo.toString(); }

    /*********************
    //main method for testing
    public static void main( String[] args ) {

	//Below is an exercise in creating a linked list...

	
	//Create a node
	DLLNode<String> first = new DLLNode<String>( "cat", null );
	//Create a new node after the first
	first.setNext( new DLLNode<String>( "dog", null ) );
	//Create a third node after the second
	first.getNext().setNext( new DLLNode<String>( "cow", null ) );
	DLLNode temp = first; 
	while( temp != null ) {
	    System.out.println( temp );
	    temp = temp.getNext();
	}
	
    }//end main
    ***********************/
}//end class DLLNode