001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.rest.server;
018
019import static java.lang.annotation.ElementType.*;
020import static java.lang.annotation.RetentionPolicy.*;
021
022import java.lang.annotation.*;
023
024import jakarta.servlet.*;
025
026/**
027 * Identifies a method that gets called immediately after servlet initialization.
028 *
029 * <p>
030 * This method is called from within the {@link Servlet#init(ServletConfig)} method after the {@link RestContext}
031 * object has been created.
032 *
033 * <p>
034 * The only valid parameter type for this method is {@link RestContext} which can be used to retrieve information
035 * about the servlet.
036 *
037 * <h5 class='section'>Notes:</h5><ul>
038 *    <li class='note'>
039 *       The method should return <jk>void</jk> although if it does return any value, the value will be ignored.
040 *    <li class='note'>
041 *       The method should be <jk>public</jk> although other visibilities are valid if the security manager allows it.
042 *    <li class='note'>
043 *       Static methods can be used.
044 *    <li class='note'>
045 *       Multiple post-init methods can be defined on a class.
046 *       <br>Post-init methods on parent classes are invoked before post-init methods on child classes unless {@link #childFirst()} is specified.
047 *       <br>The order of Post-init method invocations within a class is alphabetical, then by parameter count, then by parameter types.
048 *    <li class='note'>
049 *       The method can throw any exception causing initialization of the servlet to fail.
050 *    <li class='note'>
051 *       Note that if you override a parent method, you probably need to call <code><jk>super</jk>.parentMethod(...)</code>.
052 *       <br>The method is still considered part of the parent class for ordering purposes even though it's
053 *       overridden by the child class.
054 * </ul>
055 */
056@Target({ METHOD })
057@Retention(RUNTIME)
058@Inherited
059public @interface RestPostInit {
060
061   /**
062    * Execute in child-first order.
063    *
064    * <p>
065    * Use this annotation if you need to perform any kind of initialization on child resources before the parent resource.
066    *
067    * <p>
068    * This method is called from within the {@link Servlet#init(ServletConfig)} method after the {@link RestContext}
069    * object has been created and after the non-child-first methods have been called.
070    *
071    * @return The annotation value.
072    */
073   boolean childFirst() default false;
074
075   /**
076    * Optional description for the exposed API.
077    *
078    * @return The annotation value.
079    * @since 9.2.0
080    */
081   String[] description() default {};
082}