Java tutorial
//////////////////////////////////////////////////////////////////////////////// // checkstyle: Checks Java source code for adherence to a set of rules. // Copyright (C) 2001-2018 the original author or authors. // // This library is free software; you can redistribute it and/or // modify it under the terms of the GNU Lesser General Public // License as published by the Free Software Foundation; either // version 2.1 of the License, or (at your option) any later version. // // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU // Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public // License along with this library; if not, write to the Free Software // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA //////////////////////////////////////////////////////////////////////////////// package com.puppycrawl.tools.checkstyle.utils; import java.io.IOException; import java.lang.reflect.Constructor; import java.lang.reflect.Modifier; import java.util.Collection; import java.util.Set; import java.util.stream.Collectors; import com.google.common.reflect.ClassPath; import com.puppycrawl.tools.checkstyle.TreeWalkerFilter; import com.puppycrawl.tools.checkstyle.api.AbstractCheck; import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck; import com.puppycrawl.tools.checkstyle.api.AuditListener; import com.puppycrawl.tools.checkstyle.api.AutomaticBean; import com.puppycrawl.tools.checkstyle.api.BeforeExecutionFileFilter; import com.puppycrawl.tools.checkstyle.api.Filter; import com.puppycrawl.tools.checkstyle.api.RootModule; /** * Contains utility methods for module reflection. * @author LuoLiangchen */ public final class ModuleReflectionUtils { /** Prevent instantiation. */ private ModuleReflectionUtils() { } /** * Gets checkstyle's modules (directly, not recursively) in the given packages. * @param packages the collection of package names to use * @param loader the class loader used to load Checkstyle package names * @return the set of checkstyle's module classes * @throws IOException if the attempt to read class path resources failed * @see #isCheckstyleModule(Class) */ public static Set<Class<?>> getCheckstyleModules(Collection<String> packages, ClassLoader loader) throws IOException { final ClassPath classPath = ClassPath.from(loader); return packages.stream().flatMap(pkg -> classPath.getTopLevelClasses(pkg).stream()) .map(ClassPath.ClassInfo::load).filter(ModuleReflectionUtils::isCheckstyleModule) .collect(Collectors.toSet()); } /** * Checks whether a class may be considered as a checkstyle module. Checkstyle's modules are * non-abstract classes, which are either checkstyle's checks, file sets, filters, file filters, * {@code TreeWalker} filters, audit listener, or root module. * @param clazz class to check. * @return true if the class may be considered as the checkstyle module. */ public static boolean isCheckstyleModule(Class<?> clazz) { return isValidCheckstyleClass(clazz) && (isCheckstyleTreeWalkerCheck(clazz) || isFileSetModule(clazz) || isFilterModule(clazz) || isFileFilterModule(clazz) || isTreeWalkerFilterModule(clazz) || isAuditListener(clazz) || isRootModule(clazz)); } /** * Checks whether a class extends 'AutomaticBean', is non-abstract, and has a default * constructor. * @param clazz class to check. * @return true if a class may be considered a valid production class. */ public static boolean isValidCheckstyleClass(Class<?> clazz) { return AutomaticBean.class.isAssignableFrom(clazz) && !Modifier.isAbstract(clazz.getModifiers()) && hasDefaultConstructor(clazz); } /** * Checks if the class has a default constructor. * @param clazz class to check * @return true if the class has a default constructor. */ private static boolean hasDefaultConstructor(Class<?> clazz) { boolean result = false; for (Constructor<?> constructor : clazz.getDeclaredConstructors()) { if (constructor.getParameterCount() == 0) { result = true; break; } } return result; } /** * Checks whether a class may be considered as the checkstyle check * which has TreeWalker as a parent. * Checkstyle's checks are classes which implement 'AbstractCheck' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle check. */ public static boolean isCheckstyleTreeWalkerCheck(Class<?> clazz) { return AbstractCheck.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle file set. * Checkstyle's file sets are classes which implement 'AbstractFileSetCheck' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle file set. */ public static boolean isFileSetModule(Class<?> clazz) { return AbstractFileSetCheck.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle filter. * Checkstyle's filters are classes which implement 'Filter' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle filter. */ public static boolean isFilterModule(Class<?> clazz) { return Filter.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle file filter. * Checkstyle's file filters are classes which implement 'BeforeExecutionFileFilter' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle file filter. */ public static boolean isFileFilterModule(Class<?> clazz) { return BeforeExecutionFileFilter.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle audit listener module. * Checkstyle's audit listener modules are classes which implement 'AuditListener' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle audit listener module. */ public static boolean isAuditListener(Class<?> clazz) { return AuditListener.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle root module. * Checkstyle's root modules are classes which implement 'RootModule' interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle root module. */ public static boolean isRootModule(Class<?> clazz) { return RootModule.class.isAssignableFrom(clazz); } /** * Checks whether a class may be considered as the checkstyle {@code TreeWalker} filter. * Checkstyle's {@code TreeWalker} filters are classes which implement 'TreeWalkerFilter' * interface. * @param clazz class to check. * @return true if a class may be considered as the checkstyle {@code TreeWalker} filter. */ public static boolean isTreeWalkerFilterModule(Class<?> clazz) { return TreeWalkerFilter.class.isAssignableFrom(clazz); } }