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 019import java.lang.annotation.Annotation; 020 021import org.springframework.lang.Nullable; 022import org.springframework.util.ClassUtils; 023 024/** 025 * A common delegate for detecting Kotlin's presence and for identifying Kotlin types. 026 * 027 * @author Juergen Hoeller 028 * @author Sebastien Deleuze 029 * @since 5.0 030 */ 031@SuppressWarnings("unchecked") 032public abstract class KotlinDetector { 033 034 @Nullable 035 private static final Class<? extends Annotation> kotlinMetadata; 036 037 private static final boolean kotlinReflectPresent; 038 039 static { 040 Class<?> metadata; 041 ClassLoader classLoader = KotlinDetector.class.getClassLoader(); 042 try { 043 metadata = ClassUtils.forName("kotlin.Metadata", classLoader); 044 } 045 catch (ClassNotFoundException ex) { 046 // Kotlin API not available - no Kotlin support 047 metadata = null; 048 } 049 kotlinMetadata = (Class<? extends Annotation>) metadata; 050 kotlinReflectPresent = ClassUtils.isPresent("kotlin.reflect.full.KClasses", classLoader); 051 } 052 053 054 /** 055 * Determine whether Kotlin is present in general. 056 */ 057 public static boolean isKotlinPresent() { 058 return (kotlinMetadata != null); 059 } 060 061 /** 062 * Determine whether Kotlin reflection is present. 063 * @since 5.1 064 */ 065 public static boolean isKotlinReflectPresent() { 066 return kotlinReflectPresent; 067 } 068 069 /** 070 * Determine whether the given {@code Class} is a Kotlin type 071 * (with Kotlin metadata present on it). 072 */ 073 public static boolean isKotlinType(Class<?> clazz) { 074 return (kotlinMetadata != null && clazz.getDeclaredAnnotation(kotlinMetadata) != null); 075 } 076 077}