content: package act.util;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   * 
   *      http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * #L%
   */
  
  import java.lang.annotation.ElementType;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  
  /**
   * Mark a controller action handler method is virtual.
   *
   * If an action handler method is virtual then framework will register
   * the route for sub classes. e.g
   *
   * <pre>
   * // The base controller provides `doIt` handler
   * public abstract class BaseController {
   *      protected abstract doPlumbingWork() {}
   *     @GetAction("doIt")
   *     @Virtual
   *     public void doIt() {
   *         doPlumbingWork();
   *         ...
   *     }
   * }
   * </pre>
   *
   * <pre>
   * // The foo implementation
   * @Controller("/foo")
   * public class FooController extends BaseController {
   *      protected void doPlumbingWork() {...}
   * }
   * </pre>
   *
   * <pre>
   * // The bar implementation
   * @Controller("/bar")
   * public class BarController extends BaseController {
   *      protected void doPlumbingWork() {...}
   * }
   * </pre>
   *
   * Because method `doIt()` in `BaseController` is marked as `@Virtual`, the framework will add the following routes
   * to routing table:
   *
   * <pre>
   * GET /foo/doIt pkg.to.FooController.doIt
   * GET /bar/doIt pkg.to.BarController.doIt
   * </pre>
   */
  @Retention(RetentionPolicy.RUNTIME)
  @Target(ElementType.METHOD)
  public @interface Virtual {
  }
  