001/* 002 * Copyright 2002-2015 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 019import org.springframework.util.ClassUtils; 020 021/** 022 * Default implementation of the {@link ParameterNameDiscoverer} strategy interface, 023 * using the Java 8 standard reflection mechanism (if available), and falling back 024 * to the ASM-based {@link LocalVariableTableParameterNameDiscoverer} for checking 025 * debug information in the class file. 026 * 027 * <p>Further discoverers may be added through {@link #addDiscoverer(ParameterNameDiscoverer)}. 028 * 029 * @author Juergen Hoeller 030 * @since 4.0 031 * @see StandardReflectionParameterNameDiscoverer 032 * @see LocalVariableTableParameterNameDiscoverer 033 */ 034public class DefaultParameterNameDiscoverer extends PrioritizedParameterNameDiscoverer { 035 036 private static final boolean standardReflectionAvailable = ClassUtils.isPresent( 037 "java.lang.reflect.Executable", DefaultParameterNameDiscoverer.class.getClassLoader()); 038 039 040 public DefaultParameterNameDiscoverer() { 041 if (standardReflectionAvailable) { 042 addDiscoverer(new StandardReflectionParameterNameDiscoverer()); 043 } 044 addDiscoverer(new LocalVariableTableParameterNameDiscoverer()); 045 } 046 047}