added "main" class as main entrypoint

src/main/java/de/szimnau/zeitlaeufer/Main.java

@@ -0,0 +1,87 @@
+package de.szimnau.zeitlaeufer;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.lang.reflect.InvocationTargetException;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import static de.szimnau.zeitlaeufer.tools.CommonTools.print;
+import static de.szimnau.zeitlaeufer.tools.CommonTools.println;
+
+public class Main {
+
+   public static void main(String[] args) throws IOException, InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+      if (args.length == 0) {
+         askParametersAndRun();
+      } else {
+         parseParametersAndRun(args);
+      }
+   }
+
+
+   private static void askParametersAndRun() throws IOException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+      var br = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
+      Map<Integer, Class<?>> classes = getAllrelevantClasses();
+      String printedClasses = classes.entrySet().stream()
+          .map(e -> e.getKey() + ": " + e.getValue().getCanonicalName().substring(e.getValue().getCanonicalName().lastIndexOf('.') + 1))
+          .reduce("", (a, b) -> a + "\n" + b);
+      print("Welcher Zeitläufer soll verwendet werden? " + printedClasses + "\n: ");
+      var num = Integer.parseInt(br.readLine());
+      Class<?> selectedClass = classes.get(num);
+      var mainMethod = selectedClass.getMethod("main", String[].class);
+      mainMethod.invoke(null, (Object) new String[0]);
+   }
+
+
+   private static Map<Integer, Class<?>> getAllrelevantClasses() {
+      InputStream stream = ClassLoader.getSystemClassLoader()
+          .getResourceAsStream("de/szimnau/zeitlaeufer");
+      var br = new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8));
+      var increment = new AtomicInteger();
+      return Collections.unmodifiableSortedMap(new TreeMap<>(
+          br.lines()
+              .filter(line -> line.endsWith(".class") && !"Main.class".equals(line))
+              .sorted()
+              .map(Main::getClass)
+              .filter(Objects::nonNull)
+              .filter(clazz ->
+                  Arrays.stream(clazz.getMethods()).anyMatch(m ->
+                      "main".equals(m.getName()) && m.getParameterCount() == 1 && m.getParameterTypes()[0] == String[].class
+                  )
+              )
+              .collect(Collectors.toMap(c -> increment.incrementAndGet(), Function.identity()))
+      ));
+   }
+
+
+   private static Class<?> getClass(String className) {
+      return getClassForName(className.substring(0, className.lastIndexOf('.')));
+   }
+
+
+   private static Class<?> getClassForName(String className) {
+      String fqnClassName = "de.szimnau.zeitlaeufer." + className;
+      try {
+         return Class.forName(fqnClassName);
+      } catch (ClassNotFoundException cnfe) {
+         println("ERROR: could not find Class for Name: de.szimnau.zeitlaeufer." + fqnClassName);
+      }
+      return null;
+   }
+
+
+   private static void parseParametersAndRun(String[] args) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+      Class<?> selectedClass = getClassForName(args[0]);
+      if (selectedClass == null) {
+         System.exit(1);
+      }
+      var mainMethod = selectedClass.getMethod("main", String[].class);
+      mainMethod.invoke(null, (Object) Arrays.copyOfRange(args, 1, args.length));
+   }
+}