001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
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011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.rest.springboot;
014
015import org.apache.juneau.rest.*;
016import org.apache.juneau.rest.annotation.*;
017import org.springframework.context.ApplicationContext;
018
019/**
020 * Implementation of a {@link RestResourceResolver} for resolving resource classes using Spring.
021 *
022 * <p>
023 * Used for resolving resource classes defined via {@link Rest#children()}.
024 *
025 * <p>
026 * A typical usage pattern for registering a Juneau REST resource class is shown below:
027 *
028 * <p class='bpcode w800'>
029 *    <ja>@Configuration</ja>
030 *    <jk>public class</jk> MySpringConfiguration {
031 *
032 *       <ja>@AutoWired</ja>
033 *       <jk>private static volatile</jk> ApplicationContext <jsf>appContext</jsf>;
034 *
035 *       <ja>@Bean</ja>
036 *       <jk>public</jk> RestResourceResolver restResourceResolver(ApplicationContext appContext) {
037 *          <jk>return new</jk> SpringRestResourceResolver(appContext);
038 *       }
039 *
040 *       <ja>@Bean</ja>
041 *       <jk>public</jk> RootRest root(RestResourceResolver resolver) {
042 *          <jk>return new</jk> RootRest().setRestResourceResolver(resolver);
043 *       }
044 *
045 *       <ja>@Bean</ja>
046 *       <jk>public</jk> ServletRegistrationBean rootRegistration(RootRest root) {
047 *          <jk>return new</jk> ServletRegistrationBean(root, <jsf>CONTEXT_ROOT</jsf>, <jsf>CONTEXT_ROOT</jsf>+<js>"/"</js>, <jsf>CONTEXT_ROOT</jsf>+<js>"/*"</js>);
048 *       }
049 * </p>
050 */
051public class SpringRestResourceResolver extends BasicRestResourceResolver {
052
053   private ApplicationContext ctx;
054
055   /**
056    * Constructor.
057    *
058    * @param ctx The spring application context object.
059    */
060   public SpringRestResourceResolver(ApplicationContext ctx) {
061      this.ctx = ctx;
062   }
063
064   @Override /* RestResourceResolver */
065   public <T> T resolve(Object parent, Class<T> c, RestContextBuilder builder, Object...args) {
066      T resource = null;
067      try {
068         resource = ctx.getBean(c);
069      } catch (Exception e) { /* Ignore */ }
070      if (resource == null)
071         resource = super.resolve(parent, c, builder);
072      return resource;
073   }
074}