/**
 * Add a {@link Plugin} class to the list of known plugins
 *
 * @param plugin the plugin class
 * @param priority the priority to give the plugin
 */
private void addPlugin(Class<? extends Plugin> plugin, PluginPriority priority) {
    switch (priority) {
        case LOW:
            lowPriorityPlugins.add(plugin);
            break;
        case HIGH:
            highPriorityPlugins.add(plugin);
            break;
        case NORMAL:
        default:
            normalPriorityPlugins.add(plugin);
            break;
    }

    SupportedOptions supportedOptionsAnnotation = plugin.getAnnotation(SupportedOptions.class);
    if (supportedOptionsAnnotation != null) {
        String[] options = supportedOptionsAnnotation.value();
        Collections.addAll(pluginSupportedOptions, options);
    }
}
 

/**
 * Analogous to {@link Processor#getSupportedOptions()}, here to allow extensions to report their
 * own.
 *
 * <p>By default, if the extension class is annotated with {@link SupportedOptions}, this will
 * return a set with the strings in the annotation. If the class is not so annotated, an empty set
 * is returned.
 *
 * @return the set of options recognized by this extension or an empty set if none
 * @see SupportedOptions
 */
public Set<String> getSupportedOptions() {
  SupportedOptions so = this.getClass().getAnnotation(SupportedOptions.class);
  if (so == null) {
    return ImmutableSet.of();
  } else {
    return ImmutableSet.copyOf(so.value());
  }
}