com.github.robtimus.junit.support.ClassUtils Maven / Gradle / Ivy
/*
* ClassUtils.java
* Copyright 2021 Rob Spoor
*
* Licensed 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 com.github.robtimus.junit.support;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.stream.Stream;
import org.junit.jupiter.api.DynamicContainer;
import org.junit.jupiter.api.DynamicTest;
import org.reflections.Reflections;
import org.reflections.scanners.Scanner;
import org.reflections.scanners.Scanners;
import org.reflections.scanners.TypeElementsScanner;
import org.reflections.util.ConfigurationBuilder;
/**
* A utility class for classes.
*
* @author Rob Spoor
*/
public final class ClassUtils {
private ClassUtils() {
}
/**
* Finds all classes in a specific package.
* This can be useful to generate tests, e.g. using {@link DynamicContainer} or {@link DynamicTest}, for all classes in a project that match
* certain criteria. These criteria can be applied as filters to the returned stream.
*
* Note that classes in the JDK itself will not be found.
*
* @param packageName The name of the package to find all classes in.
* @return A stream with all classes in the given package, as well as any sub packages.
*/
public static Stream> findClassesInPackage(String packageName) {
Scanner[] scanners = { new TypeElementsScanner().publicOnly(false), Scanners.SubTypes };
Reflections reflections = new Reflections(new ConfigurationBuilder()
.forPackage(packageName)
.addScanners(scanners));
// The following intermediate variable is necessary to keep the compiler happy.
// Without it, there's a "cannot convert from Stream> to Stream>" error,
// that is caused by the filter step
Stream> classes = Arrays.stream(scanners)
.flatMap(s -> getClassNames(reflections, s))
.filter(s -> s.startsWith(packageName))
.filter(s -> !s.contains("package-info")) //$NON-NLS-1$
.distinct()
.map(s -> toClass(s, reflections));
return classes.filter(Objects::nonNull);
}
private static Stream getClassNames(Reflections reflections, Scanner scanner) {
// Taken from Reflections.getAll; prevent the unnecessary intermediate collect step
Map> map = reflections.getStore().getOrDefault(scanner.index(), Collections.emptyMap());
return Stream.concat(map.keySet().stream(), map.values().stream().flatMap(Collection::stream));
}
/**
* Finds all classes in a specific package.
* This can be useful to generate tests, e.g. using {@link DynamicContainer} or {@link DynamicTest}, for all classes in a project that match
* certain criteria. These criteria can be applied as filters to the returned stream.
*
* Note that classes in the JDK itself will not be found.
*
* @param classInPackage A class in the package to find all classes in. It will be returned as well.
* @return A stream with all classes in the given package, as well as any sub packages.
*/
public static Stream> findClassesInPackage(Class classInPackage) {
String packageName = classInPackage.getPackage().getName();
return findClassesInPackage(packageName);
}
private static Class toClass(String className, Reflections reflections) {
return reflections.forName(className, Class.class, reflections.getConfiguration().getClassLoaders());
}
}