Minetweak Launcher

Launcher.java

package org.minetweak.launcher;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import org.apache.commons.io.IOUtils;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Launcher {
    public static Logger logger = Logger.getGlobal();
    public static DownloadConfig config;
    public static String oldJSON;
    public static String json;
    public static Gson gson = new GsonBuilder().create();
    public static File dataDirectory = new File(System.getProperty("user.home"), ".minetweak");
    public static File configFile = new File(dataDirectory, "download.cfg");

    public static void main(String[] args) throws Exception {
        logger.setLevel(Level.ALL);
        if (!dataDirectory.exists()) {
            if (!dataDirectory.mkdirs()) {
                logger.severe("Unable to create data directory at " + dataDirectory.getAbsolutePath());
            }
        }
        logger.info("Downloading Minetweak Download Configuration");
        downloadConfig();
        logger.info("Reading Minetweak Download Configuration");
        if (readConfig()) {
            logger.info("Downloading Libraries");
            downloadLibraries();
        }
        launch(args);
    }

    public static void downloadLibraries() {
        for (DownloadConfig.library lib : config.libraries) {
            logger.info("Downloading " + lib.id + " to " + lib.name + ".");
            Utils.downloadFile(dataDirectory.getAbsolutePath() + "/" + lib.name, lib.url);
            logger.info("Done downloading " + lib.id + ".");
        }
    }

    public static void downloadConfig() {
        if (configFile.exists()) {
            try {
                oldJSON = IOUtils.toString(new FileReader(configFile));
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        Utils.downloadFile(configFile.getAbsolutePath(), "https://gist.github.com/kaendfinger/5941105/raw/downloadInfo.json");
    }

    public static boolean readConfig() {
        try {
            json = IOUtils.toString(new FileReader(configFile));
        } catch (IOException e) {
            e.printStackTrace();
        }
        config = gson.fromJson(json, DownloadConfig.class);
        if (json.equals(oldJSON)) {
            logger.info("Download Config Up-to-date!");
            return false;
        }
        return true;
    }

    public static void launch(String[] args) throws Exception {
        List<URL> jarPaths = new ArrayList<URL>();

        for (DownloadConfig.library lib : config.libraries) {
            jarPaths.add(new File(dataDirectory.getAbsolutePath() + "/" + lib.name).toURI().toURL());
        }
        URL[] urls = jarPaths.toArray(new URL[jarPaths.size()]);
        for (URL url : urls) {
            System.out.println("JAR: " + url);
        }
        URLClassLoader loader = new URLClassLoader(urls, Launcher.class.getClassLoader());
        Class clazz = loader.loadClass("org.minetweak.Minetweak");
        if (clazz==null) {
            logger.severe("Unable to launch Minetweak. Could not find class org.minetweak.Minetweak!");
            System.exit(1);
        }
        Method method = clazz.getDeclaredMethod("main", String[].class);
        if (method==null) {
            logger.severe("Unable to launch Minetweak. Could not invoke method main(String[])!");
            System.exit(1);
        }
        try {
            method.invoke(null, args);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}