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.arg;
018
019import static org.apache.juneau.common.utils.StringUtils.*;
020
021import java.lang.annotation.*;
022
023import org.apache.juneau.cp.*;
024import org.apache.juneau.reflect.*;
025import org.apache.juneau.rest.*;
026import org.apache.juneau.rest.annotation.*;
027
028/**
029 * Resolves method parameters on {@link RestOp}-annotated Java methods by retrieving them by type from the REST object bean store.
030 *
031 * <p>
032 * The parameter value is resolved using:
033 * <p class='bjava'>
034 *    <jv>opSession</jv>
035 *       .{@link RestOpSession#getBeanStore() getBeanStore}()
036 *       .{@link BeanStore#getBean(Class) getBean}(<jv>type</jv>);
037 * </p>
038 *
039 * <p>
040 * This is the default parameter resolver if no other applicable parameter resolvers could be found.
041 *
042 * <h5 class='section'>See Also:</h5><ul>
043 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JavaMethodParameters">Java Method Parameters</a>
044 * </ul>
045 */
046public class DefaultArg implements RestOpArg {
047
048   private final Class<?> type;
049   private final String name;
050   private final ParamInfo paramInfo;
051
052   /**
053    * Static creator.
054    *
055    * @param paramInfo The Java method parameter being resolved.
056    * @return A new {@link DefaultArg}, never <jk>null</jk>.
057    */
058   public static DefaultArg create(ParamInfo paramInfo) {
059      return new DefaultArg(paramInfo);
060   }
061
062   /**
063    * Constructor.
064    *
065    * @param paramInfo The Java method parameter being resolved.
066    */
067   protected DefaultArg(ParamInfo paramInfo) {
068      this.type = paramInfo.getParameterType().inner();
069      this.paramInfo = paramInfo;
070      this.name = findBeanName(paramInfo);
071   }
072
073   //-----------------------------------------------------------------------------------------------------------------
074   // Helper methods
075   //-----------------------------------------------------------------------------------------------------------------
076   private String findBeanName(ParamInfo pi) {
077      Annotation n = pi.getAnnotation(Annotation.class, x -> x.annotationType().getSimpleName().equals("Named"));
078      if (n != null)
079         return AnnotationInfo.of((ClassInfo)null, n).getValue(String.class, "value", NOT_EMPTY).orElse(null);
080      return null;
081   }
082
083   @Override /* RestOpArg */
084   public Object resolve(RestOpSession opSession) throws Exception {
085      return opSession.getBeanStore().getBean(type, name).orElseThrow(()->new ArgException(paramInfo, "Could not resolve bean type {0}", type.getName()));
086   }
087}