package plan9.lib; //// keys//// via Limbo version by Vita Nuova, MIT Licence//// Java version Copyright © 2012 Coraid Inc import java.util.ArrayList;import java.util.Iterator;import java.util.Collections; import plan9.lib.Strings;import plan9.lib.Attr;import plan9.lib.Attrs; /** * Keys are parsed into a type that stores the visible and secret attributes (the ones starting with "!") separately. */public class Key {	public Attrs	visible;	// public knowledge	public Attrs	secrets;	// something to hide 	public Key(Attrs attrs){	// mixture of visible and secret		visible = new Attrs();		secrets = new Attrs();		Attr proto = null;		for(Attr a : attrs){			if(proto == null && a.name.equals("proto"))				proto = a;			else if(a.isPublic())				visible.add(a);			else				secrets.add(a);		}		if(proto != null)			visible.add(0, proto);	// push proto to the front	} 	/** Parse the string s into the Key representation */	public Key(String s){		this(new Attrs(s));	} 	/** Return the value of the first instance of name=value in the key */	public String findattrval(String name){		if(name.length() == 0)			return null;		if(name.charAt(0) == '!')			return secrets.findattrval(name);		return visible.findattrval(name);	} 	/** Return a string that represents the key in textual form, but stripping the values from the secret attributes */	public String toString(){		StringBuilder bs = new StringBuilder(64);		bs.append(visible);		boolean sp = bs.length() != 0;		for(Attr a : secrets){			if(sp)				bs.append(' ');			bs.append(a.name);			bs.append('?');		}		return bs.toString();	} 	/** Return a string that represents the key in textual form, including the values of secret attributes. NOT TO BE USED LIGHTLY */	public String fullText(){		StringBuilder bs = new StringBuilder(64);		bs.append(visible);		if(bs.length() != 0 && secrets != null)			bs.append(' ');		return bs.append(secrets).toString();	} 	/** Return true iff the key matches the given set of attributes */	public boolean matchattrs(Attrs attrs){		for(Attr a : attrs){			if(!visible.matchattr(a) && !secrets.matchattr(a))				return false;		}		return true;	} 	/** Given a set of attribute names that must have values, return a string that lists the missing values in the form of a key template */	public String requires(String[] names){		StringBuilder bs = new StringBuilder(64);		for(String name : names){			if(name == null || name.length() == 0)				continue;			if(name.charAt(0) == '!'){				if(secrets.findattr(name) != null)					continue;			}else if(visible.findattr(name) != null)				continue;			if(bs.length() > 0)				bs.append(' ');			bs.append(name);		}		if(bs.length() > 0)			return bs.toString();		return null;	}}