| /* |
| * 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; |
| |
| /** |
| * <p>Utility methods focusing on inheritance.</p> |
| * |
| * @since 3.2 |
| */ |
| public class InheritanceUtils { |
| |
| /** |
| * <p>{@link InheritanceUtils} instances should NOT be constructed in standard programming. |
| * Instead, the class should be used as |
| * {@code MethodUtils.getAccessibleMethod(method)}.</p> |
| * |
| * <p>This constructor is {@code public} to permit tools that require a JavaBean |
| * instance to operate.</p> |
| */ |
| public InheritanceUtils() { |
| } |
| |
| /** |
| * <p>Returns the number of inheritance hops between two classes.</p> |
| * |
| * @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; |
| } |
| } |