samer@0: /*
samer@0:  *	Properties.java	
samer@0:  *
samer@0:  *	Copyright (c) 2001, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS IS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package	samer.core.util;
samer@0: import	samer.core.*;
samer@0: import	java.io.*;
samer@0: 
samer@0: public class Properties extends Environment
samer@0: {
samer@0: 	protected java.util.Properties	props;
samer@0: 	protected boolean	writable;
samer@0: 
samer@0: 	public Properties(Environment parent) { 
samer@0: 		this(parent,parent.node(),new java.util.Properties());
samer@0: 	}
samer@0: 	public Properties(Environment parent, java.util.Properties pr) {
samer@0: 		this(parent,parent.node(),pr);
samer@0: 	}
samer@0: 	public Properties(Environment parent, Node n) {
samer@0: 		this(parent,n,new java.util.Properties());
samer@0: 	}
samer@0: 	public Properties(Environment parent, Node n, java.util.Properties pr) {
samer@0: 		super(parent,n); props=pr; writable=true;
samer@0: 	}
samer@0: 
samer@0: 	public void save(OutputStream out) throws Exception { props.store(out,"properties"); }
samer@0: 	public void load(InputStream in) throws Exception { props.load(in); }
samer@0: 	public void setWritable(boolean f) { writable=f; }
samer@0: 	protected class Property implements Binding
samer@0: 	{
samer@0: 		String	nm;
samer@0: 		String	vl;
samer@0: 		int		sc;
samer@0: 
samer@0: 		Property(String n, String v, int s) { 
samer@0: 			nm=n; sc=s;
samer@0: 			vl = v.equals("~default") ? null : v;
samer@0: 		}
samer@0: 
samer@0: 		public String	name() { return abs(nm); }		
samer@0: 		public int		score() { return sc; }
samer@0: 
samer@0: 		public Object	get() { return vl; }
samer@0: 		public Object	get(Codec c, Object def) { return c.decode(vl==null?def:vl); }
samer@0: 		public void		get(Autocoder obj) { obj.decode(vl); }
samer@0: 
samer@0: 		public void		set(Object obj) { props.put(nm,(String)obj); }
samer@0: 		public void		remove() { props.remove(nm); }
samer@0: 	}
samer@0: 
samer@0: 	public void store(String name, Autocoder o) {
samer@0: 		if (writable && belongs(name)) props.put(rel(name),o.string());
samer@0: 		else parent.store(name,o);
samer@0: 	}
samer@0: 	public void store(String name, Object o, Codec c) {
samer@0: 		if (writable && belongs(name)) props.put(rel(name),c.string(o));
samer@0: 		else parent.store(name,o,c);
samer@0: 	}
samer@0: 
samer@0: 	public Datum datum(String name) 
samer@0: 	{
samer@0: 		Datum local=localFind(rel(name)); // localised name
samer@0: 
samer@0: 		if (local.score()>0) { 
samer@0: 			// if match is less than perfect, get parent's best match
samer@0: 			Datum inherited=parent.datum(abs(name));
samer@0: 			if (inherited.score()<local.score()) return inherited;
samer@0: 		}
samer@0: 		return local;
samer@0: 	}
samer@0: 
samer@0: 	public Binding binding(String name) 
samer@0: 	{
samer@0: 		Binding local=localFind(rel(name)); // localised name
samer@0: 
samer@0: 		if (local.score()>0) { 
samer@0: 			Binding inherited=parent.binding(abs(name));
samer@0: 			if (inherited.score()<local.score()) return inherited;
samer@0: 		}
samer@0: 		return local;
samer@0: 	}
samer@0: 
samer@0: 	public Iterator data()
samer@0: 	{
samer@0: 		return new CompoundIterator( new Iterator() {
samer@0: 			java.util.Enumeration enu=props.keys();
samer@0: 			public boolean hasNext() { return enu.hasMoreElements(); }
samer@0: 			public Datum next() {
samer@0: 				String key=(String)enu.nextElement();
samer@0: 				return new Property(key,props.getProperty(key),0);
samer@0: 		} }, parent.data() );
samer@0: 	}
samer@0: 
samer@0: 	public Binding localFind(String key) 
samer@0: 	{
samer@0: 		String	val, pname = '.'+key;
samer@0: 
samer@0: 		for (int i=0, s=0; i>=0; s++) {
samer@0: 			pname = pname.substring(i+1);
samer@0: 			val=props.getProperty(pname); 
samer@0: 			if (val!=null) return new Property(pname,val,s);
samer@0: 			i = pname.indexOf('.');
samer@0: 		}
samer@0: 		return Null;
samer@0: 	}
samer@0: }
samer@0: