Created the JavaVersionManager.java

src/main/java/de/gnmyt/mcdash/api/JavaVersionManager.java

@@ -0,0 +1,108 @@
+package de.gnmyt.mcdash.api;
+
+import de.gnmyt.mcdash.MCDashWrapper;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+import org.apache.commons.io.FileUtils;
+import org.rauschig.jarchivelib.Archiver;
+import org.rauschig.jarchivelib.ArchiverFactory;
+
+import java.io.File;
+import java.io.FileFilter;
+
+public class JavaVersionManager {
+
+    private static final Logger LOG = new Logger(JavaVersionManager.class);
+    private static final OkHttpClient client = new OkHttpClient();
+    private static final File javaFolder = MCDashWrapper.getDataSource("versions/jre");
+    private static final String DL_URL = "https://api.adoptium.net/v3/binary/latest/%s/ga/%s/%s/jre/hotspot/normal/adoptium";
+
+    /**
+     * Basic constructor of the {@link JavaVersionManager}
+     *
+     * <p>
+     * This will create the jre folder if it doesn't exist
+     * </p>
+     */
+    public JavaVersionManager() {
+        if (!javaFolder.exists() && !javaFolder.mkdirs()) {
+            LOG.error("An error occurred while creating the java folder");
+        }
+    }
+
+
+    /**
+     * Gets the java version of a specific minecraft version
+     *
+     * @param minecraftVersion the minecraft version
+     * @return the java version
+     */
+    public int getJavaVersion(String minecraftVersion) {
+        int versionNumber = Integer.parseInt(minecraftVersion.split("\\.")[1]);
+
+        if (versionNumber >= 17) return 17;
+        if (versionNumber == 16) return 16;
+        if (versionNumber >= 12) return 11;
+
+        return 8;
+    }
+
+    /**
+     * Gets the path of a specific java version
+     * @param minecraftVersion the minecraft version
+     * @return the path of the java version
+     */
+    public String getPath(String minecraftVersion) {
+        File javaPath = new File(javaFolder, getJavaVersion(minecraftVersion) + "/bin/java"
+                + (System.getProperty("os.name").toLowerCase().contains("win") ? ".exe" : ""));
+
+        if (!javaPath.exists()) {
+            LOG.info("The java version " + getJavaVersion(minecraftVersion) + " is not installed. Installing it now...");
+            installJavaVersion(getJavaVersion(minecraftVersion));
+        }
+
+        return javaPath.getAbsolutePath();
+    }
+
+    /**
+     * Installs a specific java version
+     * @param version the version
+     */
+    public void installJavaVersion(int version) {
+        String url = String.format(DL_URL, version, System.getProperty("os.name").toLowerCase().contains("win") ? "windows" : "linux",
+                System.getProperty("os.arch").contains("64") ? "x64" : "x32");
+
+        try {
+            Response response = client.newCall(new Request.Builder().url(url).build()).execute();
+            if (!response.isSuccessful()) {
+                LOG.error("An error occurred while downloading the java version: " + response.message());
+                return;
+            }
+
+            File javaFile = new File(javaFolder, version + (System.getProperty("os.name").toLowerCase().contains("win") ? ".zip" : ".tar.gz"));
+            FileUtils.copyToFile(response.body().byteStream(), javaFile);
+
+            Archiver archiver = ArchiverFactory.createArchiver(javaFile);
+            archiver.extract(javaFile, javaFolder);
+
+            javaFile.delete();
+
+            FileFilter filter = pathname -> pathname.getName().contains("jre") && pathname.getPath().contains(version + "");
+
+            File[] files = javaFolder.listFiles(filter);
+
+            if (files.length == 0) {
+                LOG.error("An error occurred while extracting the java version");
+                return;
+            }
+
+            FileUtils.moveDirectory(files[0], new File(javaFolder, String.valueOf(version)));
+
+            LOG.info("The java version " + version + " has been successfully installed");
+        } catch (Exception e) {
+            LOG.error("An error occurred while downloading the java version: " + e.getMessage());
+        }
+    }
+
+}