Java tutorial
/* * The MIT License * * Copyright (c) 2016 CloudBees, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. * */ package jenkins.plugins.git; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.util.Arrays; import java.util.List; import javax.annotation.Nonnull; import org.apache.commons.lang.ClassUtils; import org.apache.commons.lang.Validate; /** * Helper to identify methods that have not been implemented / overridden. */ class MethodUtils { /** * Checks if the method defined on the base type with the given arguments * are overridden in the given derived type. */ // TODO replace with core utility method once JENKINS-30002 is available in base version of Jenkins static boolean isOverridden(@Nonnull Class base, @Nonnull Class derived, @Nonnull String methodName, @Nonnull Class... types) { Method baseMethod = getMethodImpl(base, methodName, types); Method derivedMethod = getMethodImpl(derived, methodName, types); return baseMethod == null ? derivedMethod != null && !Modifier.isAbstract(derivedMethod.getModifiers()) : !baseMethod.equals(derivedMethod); } /** * <p>Retrieves a method whether or not it's accessible. If no such method * can be found, return {@code null}.</p> * * @param cls The class that will be subjected to the method search * @param methodName The method that we wish to call * @param parameterTypes Argument class types * @return The method */ static Method getMethodImpl(final Class<?> cls, final String methodName, final Class<?>... parameterTypes) { Validate.notNull(cls, "Null class not allowed."); Validate.notEmpty(methodName, "Null or blank methodName not allowed."); // fast path, check if directly declared on the class itself for (final Method method : cls.getDeclaredMethods()) { if (methodName.equals(method.getName()) && Arrays.equals(parameterTypes, method.getParameterTypes())) { return method; } } if (!cls.isInterface()) { // ok, now check if directly implemented on a superclass // Java 8: note that super-interface implementations trump default methods for (Class<?> klass = cls.getSuperclass(); klass != null; klass = klass.getSuperclass()) { for (final Method method : klass.getDeclaredMethods()) { if (methodName.equals(method.getName()) && Arrays.equals(parameterTypes, method.getParameterTypes())) { return method; } } } } // ok, now we are looking for an interface method... the most specific one // in the event that we have two unrelated interfaces both declaring a method of the same name // we will give up and say we could not find the method (the logic here is that we are primarily // checking for overrides, in the event of a Java 8 default method, that default only // applies if there is no conflict from an unrelated interface... thus if there are // default methods and they are unrelated then they don't exist... if there are multiple unrelated // abstract methods... well they won't count as a non-abstract implementation Method res = null; for (final Class<?> klass : (List<Class<?>>) ClassUtils.getAllInterfaces(cls)) { for (final Method method : klass.getDeclaredMethods()) { if (methodName.equals(method.getName()) && Arrays.equals(parameterTypes, method.getParameterTypes())) { if (res == null) { res = method; } else { Class<?> c = res.getDeclaringClass(); if (c == klass) { // match, ignore } else if (c.isAssignableFrom(klass)) { // this is a more specific match res = method; } else if (!klass.isAssignableFrom(c)) { // multiple overlapping interfaces declare this method and there is no common ancestor return null; } } } } } return res; } }