001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
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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.arg;
014
015import static org.apache.juneau.common.internal.StringUtils.*;
016
017import java.lang.annotation.*;
018
019import org.apache.juneau.cp.*;
020import org.apache.juneau.reflect.*;
021import org.apache.juneau.rest.*;
022import org.apache.juneau.rest.annotation.*;
023
024/**
025 * Resolves method parameters on {@link RestOp}-annotated Java methods by retrieving them by type from the REST object bean store.
026 *
027 * <p>
028 * The parameter value is resolved using:
029 * <p class='bjava'>
030 *    <jv>opSession</jv>
031 *       .{@link RestOpSession#getBeanStore() getBeanStore}()
032 *       .{@link BeanStore#getBean(Class) getBean}(<jv>type</jv>);
033 * </p>
034 *
035 * <p>
036 * This is the default parameter resolver if no other applicable parameter resolvers could be found.
037 *
038 * <h5 class='section'>See Also:</h5><ul>
039 *    <li class='link'><a class="doclink" href="../../../../../index.html#jrs.JavaMethodParameters">Java Method Parameters</a>
040 * </ul>
041 */
042public class DefaultArg implements RestOpArg {
043
044   private final Class<?> type;
045   private final String name;
046   private final ParamInfo paramInfo;
047
048   /**
049    * Static creator.
050    *
051    * @param paramInfo The Java method parameter being resolved.
052    * @return A new {@link DefaultArg}, never <jk>null</jk>.
053    */
054   public static DefaultArg create(ParamInfo paramInfo) {
055      return new DefaultArg(paramInfo);
056   }
057
058   /**
059    * Constructor.
060    *
061    * @param paramInfo The Java method parameter being resolved.
062    */
063   protected DefaultArg(ParamInfo paramInfo) {
064      this.type = paramInfo.getParameterType().inner();
065      this.paramInfo = paramInfo;
066      this.name = findBeanName(paramInfo);
067   }
068
069   //-----------------------------------------------------------------------------------------------------------------
070   // Helper methods
071   //-----------------------------------------------------------------------------------------------------------------
072   private String findBeanName(ParamInfo pi) {
073      Annotation n = pi.getAnnotation(Annotation.class, x -> x.annotationType().getSimpleName().equals("Named"));
074      if (n != null)
075         return AnnotationInfo.of((ClassInfo)null, n).getValue(String.class, "value", NOT_EMPTY).orElse(null);
076      return null;
077   }
078
079   @Override /* RestOpArg */
080   public Object resolve(RestOpSession opSession) throws Exception {
081      return opSession.getBeanStore().getBean(type, name).orElseThrow(()->new ArgException(paramInfo, "Could not resolve bean type {0}", type.getName()));
082   }
083}