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/*
* 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)}.
*
* <p>This constructor is {@code public} to permit tools that require a JavaBean
* instance to operate.</p>
*/
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;
}
}
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