/**
 * An interface for linear objects.  Designed to support both
 * static and dynamic implementation.
 */
public interface Linear {
  /** 
   * Add an element. 
   * Precondition: There is space for another element.
   * Precondition: The element to be added is not null.
   * Postcondition: The element is added to the linear structure.
   * Postcondition: The size of the structure increases by 1.
   */
  public void add(Object elt);

  /**
   * Delete and return an element.  Which element is removed is determined
   * by the ``deletion strategy'' of the particular linear structure.
   * Precondition: The structure is not empty.
   * Postcondition: Returns an element in the structure.
   * Postcondition: Deletes an element from the structure.
   * Postconditoin: The size of the structure decreases by 1.
   */ 
  public Object remove();

  /**
   * Is the structure full?  (That is, it has no space remaining.)
   */
  public boolean isFull();

  /**
   * Is the structure empty?  (That is, it has no elements.)
   */
  public boolean isEmpty();
} // interface Linear