import java.util.*;

/** MultiHashMap is a subclass of HashMap designed to work with
 * multiple associations.
 * 
 * 
 **/
public class MultiHashMap extends HashMap implements MultiMap {


    /** Constructs a new, empty map with the specified initial
     * capacity and the specified load factor.
     **/
    public MultiHashMap(int initialCapacity, float loadFactor) {
	super(initialCapacity, loadFactor);
    }

    /** Constructs a new, empty map with the specified initial
     * capacity and default load factor, which is 0.75.
     **/
    public MultiHashMap(int initialCapacity) {
	super(initialCapacity);
    }

    /** Constructs a new, empty map with a default capacity and load
     * factor, which is 0.75.
     **/
    public MultiHashMap() {
	super();
    }

    /** Constructs a new map with the same mappings as the given
     * map. The map is created with a capacity of twice the number of
     * mappings in the given map or 11 (whichever is greater), and a
     * default load factor, which is 0.75.
     **/
    public MultiHashMap(Map t) {
	super();
	this.putAll(t);
    }


    /** Returns the most recently mapped value to which this map maps
     * the specified key. Returns <i>null</i> if the map contains no
     * mapping for this key. A return value of null does not
     * necessarily indicate that the map contains no mapping for the
     * key; it's also possible that the map explicitly maps the key to
     * null. The containsKey operation may be used to distinguish
     * these two cases.
     * 
     * @returns: the most recently assigned value to which this map
     * maps the specified key.
     **/
    public Object get(Object key) {
    }

    /** Returns an unmodifiable Collection view of all values to which
     * this map maps the specified key.  A return value of null
     * indicates that this map contains no mappings for the specified
     * key
     *
     * @returns: a Collection of values to which this map maps the
     * specified key.
     **/
    public Collection getAll(Object key) {
    }

    /** Concatenate the specified value with the original value
     * which is associated with the specified key in this map.
     * take care of the situation that the specified key
     * does not exist originally
     * @effects Concatenate the specified value with the original value
     * under the specified key
     * @returns the result of this.get(key) before adding the new value
     **/
    public Object put(Object key, Object value) {
    }

    /** Associates key with all elements of c
     *
     * @requires c != null
     * @effects for all e in specified Collection,
     *          put(key, e)
     **/ 
    public void putAll(Object key, Collection c) {
    }
    
    /** Returns true iff this mapping maps key to value
     *
     * @returns true iff getAll(key).contains(value)
     **/
    public boolean contains(Object key, Object value) { 
    }

    /** Removes a binding from key to value.
     *
     * @returns true iff key was associated with value
     **/
    public boolean remove(Object key, Object value) {
    }

}