org.apache.avro.util.ClassUtils 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
*
* https://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.avro.util;
public class ClassUtils {
private ClassUtils() {
}
/**
* Loads a class using the class loader. 1. The class loader of the current
* class is being used. 2. The thread context class loader is being used. If
* both approaches fail, returns null.
*
* @param className The name of the class to load.
* @return The class or null if no class loader could load the class.
*/
public static Class forName(String className) throws ClassNotFoundException {
return ClassUtils.forName(ClassUtils.class, className);
}
/**
* Loads a class using the class loader. 1. The class loader of the context
* class is being used. 2. The thread context class loader is being used. If
* both approaches fail, returns null.
*
* @param contextClass The name of a context class to use.
* @param className The name of the class to load
* @return The class or null if no class loader could load the class.
*/
public static Class forName(Class contextClass, String className) throws ClassNotFoundException {
Class c = null;
if (contextClass.getClassLoader() != null) {
c = forName(className, contextClass.getClassLoader());
}
if (c == null && Thread.currentThread().getContextClassLoader() != null) {
c = forName(className, Thread.currentThread().getContextClassLoader());
}
if (c == null) {
throw new ClassNotFoundException("Failed to load class" + className);
}
return c;
}
/**
* Loads a class using the class loader. 1. The class loader of the context
* class is being used. 2. The thread context class loader is being used. If
* both approaches fail, returns null.
*
* @param classLoader The classloader to use.
* @param className The name of the class to load
* @return The class or null if no class loader could load the class.
*/
public static Class forName(ClassLoader classLoader, String className) throws ClassNotFoundException {
Class c = null;
if (classLoader != null) {
c = forName(className, classLoader);
}
if (c == null && Thread.currentThread().getContextClassLoader() != null) {
c = forName(className, Thread.currentThread().getContextClassLoader());
}
if (c == null) {
throw new ClassNotFoundException("Failed to load class" + className);
}
return c;
}
/**
* Loads a {@link Class} from the specified {@link ClassLoader} without throwing
* {@link ClassNotFoundException}.
*
* @param className
* @param classLoader
* @return
*/
private static Class forName(String className, ClassLoader classLoader) {
Class c = null;
if (classLoader != null && className != null) {
try {
c = Class.forName(className, true, classLoader);
} catch (ClassNotFoundException e) {
// Ignore and return null
}
}
return c;
}
}