/**
     * <p>Returns a descriptor which is equal to this descriptor.
     * Changes to the returned descriptor will have no effect on this
     * descriptor, and vice versa.  If this descriptor is immutable,
     * it may fulfill this condition by returning itself.</p>
     * @exception RuntimeOperationsException for illegal value for field names
     * or field values.
     * If the descriptor construction fails for any reason, this exception will
     * be thrown.
     * @return A descriptor which is equal to this descriptor.
     */
    public Object clone() throws RuntimeOperationsException;


    /**
     * Returns true if all of the fields have legal values given their
     * names.
     *
     * @return true if the values are legal.
     *
     * @exception RuntimeOperationsException If the validity checking fails for
     * any reason, this exception will be thrown.
     * The method returns false if the descriptor is not valid, but throws
     * this exception if the attempt to determine validity fails.
     */
    public boolean isValid() throws RuntimeOperationsException;
    
    /**
     * Compares this descriptor to the given object.  The objects are equal if
     * the given object is also a Descriptor, and if the two Descriptors have
     * the same field names (possibly differing in case) and the same
     * associated values.  The respective values for a field in the two
     * Descriptors are equal if the following conditions hold:</p>
     * 
     * <ul>
     * <li>If one value is null then the other must be too.</li>
     * <li>If one value is a primitive array then the other must be a primitive
     * array of the same type with the same elements.</li>
     * <li>If one value is an object array then the other must be too and
     * {@link Arrays#deepEquals(Object[],Object[])} must return true.</li>
     * <li>Otherwise {@link Object#equals(Object)} must return true.</li>
     * </ul>
     *
     * @param obj the object to compare with.
     *
     * @return {@code true} if the objects are the same; {@code false}
     * otherwise.
     *
     * @since 1.6
     */
    public boolean equals(Object obj);
    
    /**
     * <p>Returns the hash code value for this descriptor.  The hash
     * code is computed as the sum of the hash codes for each field in
     * the descriptor.  The hash code of a field with name {@code n}
     * and value {@code v} is {@code n.toLowerCase().hashCode() ^ h}.
     * Here {@code h} is the hash code of {@code v}, computed as
     * follows:</p>
     * 
     * <ul>
     * <li>If {@code v} is null then {@code h} is 0.</li>
     * <li>If {@code v} is a primitive array then {@code h} is computed using
     * the appropriate overloading of {@code java.util.Arrays.hashCode}.</li>
     * <li>If {@code v} is an object array then {@code h} is computed using
     * {@link Arrays#deepHashCode(Object[])}.</li>
     * <li>Otherwise {@code h} is {@code v.hashCode()}.</li>
     * </ul>
     *
     * @return A hash code value for this object.
     *
     * @since 1.6
     */
    public int hashCode();
}