* @param <K> the type of keys maintained by this map
 * @param <V> the type of mapped values
 *
 * @author  Josh Bloch
 * @see HashMap
 * @see TreeMap
 * @see Hashtable
 * @see SortedMap
 * @see Collection
 * @see Set
 * @since 1.2
 */
public interface Map<K,V> {
    // Query Operations

    /**
     * Returns the number of key-value mappings in this map.  If the
     * map contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
     * <tt>Integer.MAX_VALUE</tt>.
     *
     * @return the number of key-value mappings in this map
     */
    int size();

    /**
     * Returns <tt>true</tt> if this map contains no key-value mappings.
     *
     * @return <tt>true</tt> if this map contains no key-value mappings
     */
    boolean isEmpty();

    /**
     * Retorna <tt>true</tt> si este diccionario contiene una definicion para
     * la clave especificada. Mas formalmente, retorna <tt>true</tt> si y solo
     * si este mapa contiene una definición para una clave <tt>k</tt> tal que
     * <tt> (clave == null ? k == null : clave.equals(k)) </tt>.
     *
     * @param key <completar>
     * @returns <completar>
     * @<completar> ClassCastException if the key is of an inappropriate type for
     *         this map
     * @<completar> NullPointerException if the specified key is null and this map
     *         does not permit null keys
     */
    boolean containsKey(Object key);

}