package java.util;

public interface Iterator 
{
    /**
     * Returns true if the iteration has more elements. (In other
     * words, returns true if next would return an element
     * rather than throwing an exception.)
     *
     * @return true if the iterator has more elements.
     */
    boolean hasNext();

    /**
     * Returns the next element in the iteration.
     *
     * @returns the next element in the iteration.
     * @exception NoSuchElementException iteration has no more elements.
     */
    Object next();

    /**
     * 
     * Removes from the underlying collection the last element returned by the
     * iterator (optional operation).  This method can be called only once per
     * call to next.  The behavior of an iterator is unspecified if
     * the underlying collection is modified while the iteration is in
     * progress in any way other than by calling this method.
     *
     * @exception UnsupportedOperationException if the remove
     *		  operation is not supported by this Iterator.
     
     * @exception IllegalStateException if the next method has not
     *		  yet been called, or the remove method has already
     *		  been called after the last call to the next
     *		  method.
     */
    void remove();
}