/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.lang3.reflect; import org.apache.commons.lang3.BooleanUtils; /** * Utility methods focusing on inheritance. * * @since 3.2 */ public class InheritanceUtils { /** * {@link InheritanceUtils} instances should NOT be constructed in standard programming. * Instead, the class should be used as * {@code MethodUtils.getAccessibleMethod(method)}. * *

This constructor is {@code public} to permit tools that require a JavaBean * instance to operate.

*/ public InheritanceUtils() { } /** * Returns the number of inheritance hops between two classes. * * @param child the child class, may be {@code null} * @param parent the parent class, may be {@code null} * @return the number of generations between the child and parent; 0 if the same class; * -1 if the classes are not related as child and parent (includes where either class is null) * @since 3.2 */ public static int distance(final Class child, final Class parent) { if (child == null || parent == null) { return -1; } if (child.equals(parent)) { return 0; } final Class cParent = child.getSuperclass(); int d = BooleanUtils.toInteger(parent.equals(cParent)); if (d == 1) { return d; } d += distance(cParent, parent); return d > 0 ? d + 1 : -1; } }