package org.moparscape.msc.gs.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Properties;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

import org.moparscape.msc.config.Config;

import com.thoughtworks.xstream.XStream;

public class PersistenceManager {
	private static final XStream xstream = new XStream();

	static {
		setupAliases();
	}

	public static Object load(String filename) {
		try {
			InputStream is = new FileInputStream(new File(Config.CONF_DIR,
					filename));
			if (filename.endsWith(".gz")) {
				is = new GZIPInputStream(is);
			}
			Object rv = xstream.fromXML(is);
			return rv;
		} catch (IOException ioe) {
			Logger.error(ioe);
		}
		return null;
	}

	public static void setupAliases() {
		try {
			Properties aliases = new Properties();
			FileInputStream fis = new FileInputStream(new File(Config.CONF_DIR,
					"aliases.xml"));
			aliases.loadFromXML(fis);
			for (Enumeration<?> e = aliases.propertyNames(); e
					.hasMoreElements();) {
				String alias = (String) e.nextElement();
				Class<?> c = Class.forName((String) aliases.get(alias));
				xstream.alias(alias, c);
			}
		} catch (Exception ioe) {
			Logger.error(ioe);
		}
	}

	public static void write(String filename, Object o) {
		try {
			OutputStream os = new FileOutputStream(new File(Config.CONF_DIR,
					filename));
			if (filename.endsWith(".gz")) {
				os = new GZIPOutputStream(os);
			}
			xstream.toXML(o, os);
		} catch (IOException ioe) {
			Logger.error(ioe);
		}
	}
}