org.apache.hudi.common.util.ReflectionUtils Maven / Gradle / Ivy
/*
* 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.hudi.common.util;
import org.apache.hudi.exception.HoodieException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Stream;
/**
* A utility class for reflection.
*/
public class ReflectionUtils {
private static final Logger LOG = LoggerFactory.getLogger(ReflectionUtils.class);
private static final Map> CLAZZ_CACHE = new HashMap<>();
public static Class getClass(String clazzName) {
if (!CLAZZ_CACHE.containsKey(clazzName)) {
synchronized (CLAZZ_CACHE) {
if (!CLAZZ_CACHE.containsKey(clazzName)) {
try {
Class clazz = Class.forName(clazzName);
CLAZZ_CACHE.put(clazzName, clazz);
} catch (ClassNotFoundException e) {
throw new HoodieException("Unable to load class", e);
}
}
}
}
return CLAZZ_CACHE.get(clazzName);
}
public static T loadClass(String className) {
try {
return (T) getClass(className).newInstance();
} catch (InstantiationException | IllegalAccessException e) {
throw new HoodieException("Could not load class " + className, e);
}
}
/**
* Creates an instance of the given class. Use this version when dealing with interface types as constructor args.
*/
public static Object loadClass(String clazz, Class[] constructorArgTypes, Object... constructorArgs) {
try {
return getClass(clazz).getConstructor(constructorArgTypes).newInstance(constructorArgs);
} catch (InstantiationException | IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
throw new HoodieException("Unable to instantiate class " + clazz, e);
}
}
/**
* Check if the clazz has the target constructor or not, without throwing warn-level log.
*
* @param clazz Class name.
* @param constructorArgTypes Argument types of the constructor.
* @return
*/
public static boolean hasConstructor(String clazz, Class[] constructorArgTypes) {
return hasConstructor(clazz, constructorArgTypes, true);
}
/**
* Check if the clazz has the target constructor or not.
*
* When catch {@link HoodieException} from {@link #loadClass}, it's inconvenient to say if the exception was thrown
* due to the instantiation's own logic or missing constructor.
*
* TODO: ReflectionUtils should throw a specific exception to indicate Reflection problem.
*
* @param clazz Class name.
* @param constructorArgTypes Argument types of the constructor.
* @param silenceWarning {@code true} to use debug-level logging; otherwise, use warn-level logging.
* @return {@code true} if the constructor exists; {@code false} otherwise.
*/
public static boolean hasConstructor(String clazz, Class[] constructorArgTypes, boolean silenceWarning) {
try {
getClass(clazz).getConstructor(constructorArgTypes);
return true;
} catch (NoSuchMethodException e) {
String message = "Unable to instantiate class " + clazz;
if (silenceWarning) {
LOG.debug(message, e);
} else {
LOG.warn(message, e);
}
return false;
}
}
/**
* Creates an instance of the given class. Constructor arg types are inferred.
*/
public static Object loadClass(String clazz, Object... constructorArgs) {
Class[] constructorArgTypes = Arrays.stream(constructorArgs).map(Object::getClass).toArray(Class[]::new);
return loadClass(clazz, constructorArgTypes, constructorArgs);
}
/**
* Scans all classes accessible from the context class loader
* which belong to the given package and subpackages.
*
* @param clazz class
* @return Stream of Class names in package
*/
public static Stream getTopLevelClassesInClasspath(Class clazz) {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
String packageName = clazz.getPackage().getName();
String path = packageName.replace('.', '/');
Enumeration resources = null;
try {
resources = classLoader.getResources(path);
} catch (IOException e) {
LOG.error("Unable to fetch Resources in package " + e.getMessage());
}
List directories = new ArrayList<>();
while (Objects.requireNonNull(resources).hasMoreElements()) {
URL resource = resources.nextElement();
try {
directories.add(new File(resource.toURI()));
} catch (URISyntaxException e) {
LOG.error("Unable to get " + e.getMessage());
}
}
List classes = new ArrayList<>();
for (File directory : directories) {
classes.addAll(findClasses(directory, packageName));
}
return classes.stream();
}
/**
* Recursive method used to find all classes in a given directory and subdirs.
*
* @param directory The base directory
* @param packageName The package name for classes found inside the base directory
* @return classes in the package
*/
private static List findClasses(File directory, String packageName) {
List classes = new ArrayList<>();
if (!directory.exists()) {
return classes;
}
File[] files = directory.listFiles();
for (File file : Objects.requireNonNull(files)) {
if (file.isDirectory()) {
classes.addAll(findClasses(file, packageName + "." + file.getName()));
} else if (file.getName().endsWith(".class")) {
classes.add(packageName + '.' + file.getName().substring(0, file.getName().length() - 6));
}
}
return classes;
}
/**
* Returns whether the given two comparable values come from the same runtime class.
*/
public static boolean isSameClass(Comparable v, Comparable o) {
return v.getClass() == o.getClass();
}
/**
* Invoke a static method of a class.
* @param clazz
* @param methodName
* @param args
* @param parametersType
* @return the return value of the method
*/
public static Object invokeStaticMethod(String clazz, String methodName, Object[] args, Class... parametersType) {
try {
Method method = Class.forName(clazz).getMethod(methodName, parametersType);
return method.invoke(null, args);
} catch (ClassNotFoundException e) {
throw new HoodieException("Unable to find the class " + clazz, e);
} catch (NoSuchMethodException e) {
throw new HoodieException(String.format("Unable to find the method %s of the class %s ", methodName, clazz), e);
} catch (InvocationTargetException | IllegalAccessException e) {
throw new HoodieException(String.format("Unable to invoke the method %s of the class %s ", methodName, clazz), e);
}
}
/**
* Checks if the given class with the name is a subclass of another class.
*
* @param aClazzName Class name.
* @param superClazz Super class to check.
* @return {@code true} if {@code aClazzName} is a subclass of {@code superClazz};
* {@code false} otherwise.
*/
public static boolean isSubClass(String aClazzName, Class superClazz) {
return superClazz.isAssignableFrom(getClass(aClazzName));
}
}