public static Hashtable/*<Key,Value[]>*/ Compact(IRelation/*<Key,Value>*/ irel, Type value_type)
{
Hashtable hash = new Hashtable();
foreach(object key in irel.GetKeys())
{
ISet vals = irel.GetValues(key);
if(vals.Count == 0)
continue;
System.Array array_vals = System.Array.CreateInstance(value_type, vals.Count);
vals.CopyTo(array_vals, 0);
if (typeof(Node).IsAssignableFrom(value_type))
{
Array.Sort(array_vals, DataStructUtil.NodeComparer);
}
hash.Add(key, array_vals);
}
return hash;
}
public virtual bool AddRelation(IRelation relation)
{
if(relation == null) return false;
bool changed = false;
foreach(object key in relation.GetKeys())
if(this.AddAll(key, relation.GetValues(key)))
changed = true;
return changed;
}