Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/updatables/InverseMapping.java
*/
    public Collection addMapping(Object key, Object value) {
        elementsToAdapters.put(key, value);
        
        Collection existingInverse = (Collection)adaptersToElementCollection.get(value);
        if (existingInverse == null) {
            existingInverse = new HashSet();
            adaptersToElementCollection.put(value, existingInverse);
        }
        existingInverse.add(key);
        
        return existingInverse;
    }
    
    public Collection getValues() {
    	return adaptersToElementCollection.keySet();
    }
    /**
     * Returns the set of keys that map onto the given value
     * @param value
     * @return the set of keys that map onto the given value, or the empty set if none
     */
    public Collection getInverse(Object value) {
        Collection result = (Collection) adaptersToElementCollection.get(value);
        if (result == null) {
            return Collections.EMPTY_SET;
        }
        return result;
    }
    /**