001/*
002 * Copyright 2002-2018 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 java.lang.reflect.Constructor;
020import java.lang.reflect.Method;
021
022import org.springframework.lang.Nullable;
023
024/**
025 * Interface to discover parameter names for methods and constructors.
026 *
027 * <p>Parameter name discovery is not always possible, but various strategies are
028 * available to try, such as looking for debug information that may have been
029 * emitted at compile time, and looking for argname annotation values optionally
030 * accompanying AspectJ annotated methods.
031 *
032 * @author Rod Johnson
033 * @author Adrian Colyer
034 * @since 2.0
035 */
036public interface ParameterNameDiscoverer {
037
038        /**
039         * Return parameter names for a method, or {@code null} if they cannot be determined.
040         * <p>Individual entries in the array may be {@code null} if parameter names are only
041         * available for some parameters of the given method but not for others. However,
042         * it is recommended to use stub parameter names instead wherever feasible.
043         * @param method the method to find parameter names for
044         * @return an array of parameter names if the names can be resolved,
045         * or {@code null} if they cannot
046         */
047        @Nullable
048        String[] getParameterNames(Method method);
049
050        /**
051         * Return parameter names for a constructor, or {@code null} if they cannot be determined.
052         * <p>Individual entries in the array may be {@code null} if parameter names are only
053         * available for some parameters of the given constructor but not for others. However,
054         * it is recommended to use stub parameter names instead wherever feasible.
055         * @param ctor the constructor to find parameter names for
056         * @return an array of parameter names if the names can be resolved,
057         * or {@code null} if they cannot
058         */
059        @Nullable
060        String[] getParameterNames(Constructor<?> ctor);
061
062}