//----------------------------------------------------------------------------
// SListInterface.java           by Dale/Joyce/Weems                 Chapter 6
//
// Interface that defines methods common to our various kinds of list.
// Our intention is that this interface will be extended by other interfaces
// directly related to the specific kind of list. Those interfaces, in turn,
// will be implemented by classes.
//
// The lists are unbounded, allow duplicate elements, but do not allow null
// elements. As a general precondition, null elements are not passed as 
// arguments to any of the methods. The lists are serializable.
//
// The list has a special property called the current position - the position 
// of the next element to be accessed by getNext during an iteration through 
// the list. Only reset and getNext affect the current position.
//----------------------------------------------------------------------------

package ch06.serLists;

public interface SListInterface
{
  int size();
  // Returns the number of elements on this list.

  boolean contains (Object element);
  // Returns true if this list contains an element e such that 
  // e.equals(element); otherwise, returns false.
    
  boolean remove (Object element);
  // Removes an element e from this list such that e.equals(element)
  // and returns true; if no such element exists, returns false. 
  
  Object get(Object element);
  // Returns an element e from this list such that e.equals(element);
  // if no such element exists, returns null.
  
  String toString();
  // Returns a nicely formatted string that represents this list.
  
  void reset();
  // Initializes current position for an iteration through this list,
  // to the first element on this list.

  Object getNext();
  // Preconditions: The list is not empty
  //                The list has been reset
  //                The list has not been modified since the most recent reset
  //
  // Returns the element at the current position on this list.
  // If the current position is the last element, then it advances the value 
  // of the current position to the first element; otherwise, it advances
  // the value of the current position to the next element.
}