/**
   An interface that describes the operations of a set of objects.
   
   @author Charles Hoot, Frank M. Carrano 
   @version 4.0
*/
public interface SetInterface<T>
{
	/** Gets the current number of entries in this set.
       @return  The integer number of entries currently in the set. */
	public int getCurrentSize();
   
	/** Sees whether this set is empty.
       @return  True if the set is empty, or false if not. */
	public boolean isEmpty();
   
	/** Adds a new entry to this set, avoiding duplicates.
	    @param newEntry  The object to be added as a new entry.
	    @return  True if the addition is successful, or 
                false if the item already is in the set. */
	public boolean add(T newEntry);

	/** Removes a specific entry from this set, if possible.
       @param anEntry  The entry to be removed.
       @return  True if the removal was successful, or false if not. */
	public boolean remove(T anEntry);
   
	/** Removes one unspecified entry from this set, if possible.
       @return  Either the removed entry, if the removal was successful,
                or null. */
	public T remove();
   
	/** Removes all entries from this set. */
	public void clear();

	/** Tests whether this set contains a given entry.
	    @param anEntry  The entry to locate.
	    @return  True if the set contains anEntry, or false if not .*/
	public boolean contains(T anEntry);

	/** Retrieves all entries that are in this set.
		 @return  A newly allocated array of all the entries in the set. */
	public T[] toArray();
} // end SetInterface