added a basic update checker

Author: hyperdefined

src/main/java/lol/hyper/customlauncher/Main.java

@@ -20,8 +20,10 @@
 import lol.hyper.customlauncher.accounts.JSONManager;
 import lol.hyper.customlauncher.accounts.windows.MainWindow;
 import lol.hyper.customlauncher.generic.ErrorWindow;
+import lol.hyper.customlauncher.generic.InfoWindow;
 import lol.hyper.customlauncher.setup.FirstSetup;
 import lol.hyper.customlauncher.ttrupdater.TTRUpdater;
+import lol.hyper.customlauncher.updater.UpdateChecker;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.json.JSONArray;
@@ -36,6 +38,7 @@ public class Main {
 
     public static Logger logger;
     public static String pathToUse;
+    public static final String VERSION = "1.2";
 
     public static void main(String[] args) throws IOException {
         System.setProperty("log4j.configurationFile", "log4j2config.xml");
@@ -99,6 +102,11 @@ public static void main(String[] args) throws IOException {
                 updater.dispose();
             }
         }
+        if (UpdateChecker.checkForUpdates(VERSION)) {
+            JFrame infoWindow = new InfoWindow("A new version is available.\nPlease download the latest version from the GitHub.");
+            infoWindow.dispose();
+        }
+
         JFrame mainWindow = new MainWindow("CustomLauncherRewrite");
         mainWindow.dispose();
     }

src/main/java/lol/hyper/customlauncher/updater/UpdateChecker.java

@@ -0,0 +1,68 @@
+/*
+ * This file is part of CustomLauncherRewrite.
+ *
+ * CustomLauncherRewrite is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * CustomLauncherRewrite is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with CustomLauncherRewrite.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package lol.hyper.customlauncher.updater;
+
+import lol.hyper.customlauncher.invasiontracker.InvasionTracker;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.URL;
+import java.net.URLConnection;
+import java.nio.charset.StandardCharsets;
+import java.util.stream.Collectors;
+
+public class UpdateChecker {
+
+    /**
+     * Check for updates to the program.
+     * @return True if there is an update.
+     */
+    public static boolean checkForUpdates(String currentVersion) throws IOException {
+        Logger logger = LogManager.getLogger(UpdateChecker.class);
+        String remoteVersion = null;
+        URL url = new URL("https://raw.githubusercontent.com/hyperdefined/CustomLauncherRewrite/master/version");
+        URLConnection conn = url.openConnection();
+        conn.setRequestProperty(
+                "User-Agent", "CustomLauncherRewrite https://github.com/hyperdefined/CustomLauncherRewrite");
+        conn.connect();
+        BufferedReader serverResponse = new BufferedReader(new InputStreamReader(conn.getInputStream()));
+        serverResponse.close();
+
+        try (InputStream in = url.openStream()) {
+            BufferedReader reader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));
+            remoteVersion = reader.lines().collect(Collectors.joining(System.lineSeparator()));
+            reader.close();
+        } catch (IOException e) {
+            logger.error(e);
+        }
+
+        logger.info("Current version: " + currentVersion);
+        logger.info("Latest version: " + remoteVersion);
+
+        if (remoteVersion == null || remoteVersion.equalsIgnoreCase("")) {
+            logger.warn("Unable to find latest version from GitHub. The string either returned null or empty.");
+            return false;
+        }
+
+        return !remoteVersion.equals(currentVersion);
+    }
+}