org.apache.pulsar.common.util.ClassLoaderUtils Maven / Gradle / Ivy
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* 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.pulsar.common.util;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import lombok.extern.slf4j.Slf4j;
/**
* Helper methods wrt Classloading.
*/
@Slf4j
public class ClassLoaderUtils {
/**
* Load a jar.
*
* @param jar file of jar
* @return classloader
* @throws MalformedURLException
*/
public static ClassLoader loadJar(File jar) throws MalformedURLException {
java.net.URL url = jar.toURI().toURL();
return AccessController.doPrivileged(
(PrivilegedAction) () -> new URLClassLoader(new URL[]{url}));
}
public static ClassLoader extractClassLoader(File packageFile) throws Exception {
if (packageFile != null) {
return loadJar(packageFile);
}
return null;
}
public static Class loadClass(String className, ClassLoader classLoader) throws ClassNotFoundException {
Class objectClass;
try {
objectClass = Class.forName(className);
} catch (ClassNotFoundException | NoClassDefFoundError e) {
if (classLoader != null) {
objectClass = classLoader.loadClass(className);
} else {
throw e;
}
}
return objectClass;
}
public static void implementsClass(String className, Class klass, ClassLoader classLoader) {
Class objectClass;
try {
objectClass = loadClass(className, classLoader);
} catch (ClassNotFoundException | NoClassDefFoundError e) {
throw new IllegalArgumentException("Cannot find/load class " + className);
}
if (!klass.isAssignableFrom(objectClass)) {
throw new IllegalArgumentException(
String.format("%s does not implement %s", className, klass.getName()));
}
}
public static void closeClassLoader(ClassLoader classLoader) {
if (classLoader instanceof Closeable) {
try {
((Closeable) classLoader).close();
} catch (IOException e) {
log.error("Error closing classloader {}", classLoader, e);
}
}
}
}