001/* 002 * Copyright 2002-2020 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.core; 018 019/** 020 * Default implementation of the {@link ParameterNameDiscoverer} strategy interface, 021 * using the Java 8 standard reflection mechanism (if available), and falling back 022 * to the ASM-based {@link LocalVariableTableParameterNameDiscoverer} for checking 023 * debug information in the class file. 024 * 025 * <p>If a Kotlin reflection implementation is present, 026 * {@link KotlinReflectionParameterNameDiscoverer} is added first in the list and 027 * used for Kotlin classes and interfaces. When compiling or running as a GraalVM 028 * native image, the {@code KotlinReflectionParameterNameDiscoverer} is not used. 029 * 030 * <p>Further discoverers may be added through {@link #addDiscoverer(ParameterNameDiscoverer)}. 031 * 032 * @author Juergen Hoeller 033 * @author Sebastien Deleuze 034 * @author Sam Brannen 035 * @since 4.0 036 * @see StandardReflectionParameterNameDiscoverer 037 * @see LocalVariableTableParameterNameDiscoverer 038 * @see KotlinReflectionParameterNameDiscoverer 039 */ 040public class DefaultParameterNameDiscoverer extends PrioritizedParameterNameDiscoverer { 041 042 public DefaultParameterNameDiscoverer() { 043 if (KotlinDetector.isKotlinReflectPresent() && !GraalDetector.inImageCode()) { 044 addDiscoverer(new KotlinReflectionParameterNameDiscoverer()); 045 } 046 addDiscoverer(new StandardReflectionParameterNameDiscoverer()); 047 addDiscoverer(new LocalVariableTableParameterNameDiscoverer()); 048 } 049 050}