package plan9.lib; //// keys//// via Limbo version by Vita Nuova, MIT Licence// Java version Copyright © 2012 Coraid Inc//import java.lang.*;import java.util.ArrayList;import java.util.Iterator;import java.util.Collections; import plan9.lib.Strings;import plan9.lib.Attr;import plan9.lib.Attrs; public class Keys {	ArrayList<Key> keys; 	public Keys(){		keys = new ArrayList<Key>();	} 	public Key findkey(Attrs attrs){		for(Key k : keys){			if(k != null && k.matchattrs(attrs))				return k;		}		return null;	} 	public ArrayList<Key> findkeys(Attrs attrs){		ArrayList<Key> kl = new ArrayList<Key>();		for(Key k : keys){			if(k != null && k.matchattrs(attrs))				kl.add(k);		}		if(kl.size() == 0)			return null;		return kl;	} 	public int delkey(Attrs attrs){		int nk = 0;		for(Iterator<Key> i = keys.iterator(); i.hasNext();){			Key k = i.next();			if(k != null &&			   k.matchattrs(attrs)){				nk++;				i.remove();			}		}		return nk;	} 	public void addkey(Key k){		keys.add(k);	// unclear whether this should eliminate existing matching keys	} 	public Iterator<Key> iterator(){		return keys.iterator();	}};