Method getExtendingClasses

src/redempt/redlib/RedLib.java:114–145

Gets all non-abstract, non-interface classes which extend a certain class within a plugin @param plugin The plugin @param clazz The class @param The type of the class @return The list of matching classes

(Plugin plugin, Class<T> clazz)

     * @return The list of matching classes
     */
    public static <T> List<Class<? extends T>> getExtendingClasses(Plugin plugin, Class<T> clazz) {
        List<Class<? extends T>> list = new ArrayList<>();
        try {
            ClassLoader loader = plugin.getClass().getClassLoader();
            JarFile file = new JarFile(new File(plugin.getClass().getProtectionDomain().getCodeSource().getLocation().toURI()));
            Enumeration<JarEntry> entries = file.entries();
            while (entries.hasMoreElements()) {
                JarEntry entry = entries.nextElement();
                if (entry.isDirectory()) {
                    continue;
                }
                String name = entry.getName();
                if (!name.endsWith(".class")) {
                    continue;
                }
                name = name.substring(0, name.length() - 6).replace("/", ".");
                Class<?> c;
                try {
                    c = Class.forName(name, true, loader);
                } catch (ClassNotFoundException | NoClassDefFoundError ex) {
                    continue;
                }
                if (!clazz.isAssignableFrom(c) || Modifier.isAbstract(c.getModifiers()) || c.isInterface()) {
                    continue;
                }
                list.add((Class<? extends T>) c);
            }
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
        return list;
    }

}