/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.util;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.base.Supplier;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.List;
import java.util.concurrent.Callable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public final class ClassLoaderUtils {
private static final Logger LOG = LoggerFactory.getLogger(ClassLoaderUtils.class);
private static final Splitter DOT_SPLITTER = Splitter.on('.');
private ClassLoaderUtils() {
throw new UnsupportedOperationException("Utility class");
}
/**
* Runs {@link Supplier} with provided {@link ClassLoader}.
*
* <p>Invokes supplies function and makes sure that original {@link ClassLoader}
* is context {@link ClassLoader} after execution.
*
* @param cls {@link ClassLoader} to be used.
* @param function Function to be executed.
* @return Result of supplier invocation.
*/
public static <V> V withClassLoader(final ClassLoader cls, final Supplier<V> function) {
checkNotNull(cls, "Classloader should not be null");
checkNotNull(function, "Function should not be null");
final Thread currentThread = Thread.currentThread();
final ClassLoader oldCls = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(cls);
return function.get();
} finally {
currentThread.setContextClassLoader(oldCls);
}
}
/**
* Runs {@link Callable} with provided {@link ClassLoader}.
*
* Invokes supplies function and makes sure that original {@link ClassLoader}
* is context {@link ClassLoader} after execution.
*
* @param cls {@link ClassLoader} to be used.
* @param function Function to be executed.
* @return Result of callable invocation.
*/
public static <V> V withClassLoader(final ClassLoader cls, final Callable<V> function) throws Exception {
checkNotNull(cls, "Classloader should not be null");
checkNotNull(function, "Function should not be null");
final Thread currentThread = Thread.currentThread();
final ClassLoader oldCls = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(cls);
return function.call();
} finally {
currentThread.setContextClassLoader(oldCls);
}
}
public static Object construct(final Constructor<?> constructor, final List<Object> objects)
throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
final Object[] initargs = objects.toArray();
return constructor.newInstance(initargs);
}
/**
* Loads class using this supplied classloader.
*
* @param name String name of class.
*/
public static Class<?> loadClass(final ClassLoader cls, final String name) throws ClassNotFoundException {
if ("byte[]".equals(name)) {
return byte[].class;
}
if ("char[]".equals(name)) {
return char[].class;
}
return loadClass0(cls,name);
}
private static Class<?> loadClass0(final ClassLoader cls, final String name) throws ClassNotFoundException {
try {
return cls.loadClass(name);
} catch (final ClassNotFoundException e) {
final List<String> components = DOT_SPLITTER.splitToList(name);
if (isInnerClass(components)) {
final int length = components.size() - 1;
final String outerName = Joiner.on(".").join(components.subList(0, length));
final String innerName = outerName + "$" + components.get(length);
return cls.loadClass(innerName);
}
throw e;
}
}
private static boolean isInnerClass(final List<String> components) {
final int length = components.size();
if (length < 2) {
return false;
}
final String potentialOuter = components.get(length - 2);
if (potentialOuter == null) {
return false;
}
return Character.isUpperCase(potentialOuter.charAt(0));
}
public static Class<?> loadClassWithTCCL(final String name) throws ClassNotFoundException {
return loadClass(Thread.currentThread().getContextClassLoader(), name);
}
public static Class<?> tryToLoadClassWithTCCL(final String fullyQualifiedName) {
try {
return loadClassWithTCCL(fullyQualifiedName);
} catch (final ClassNotFoundException e) {
LOG.debug("Failed to load class {}", fullyQualifiedName, e);
return null;
}
}
public static <S,G,P> Class<P> findFirstGenericArgument(final Class<S> scannedClass, final Class<G> genericType) {
return withClassLoader(scannedClass.getClassLoader(), findFirstGenericArgumentTask(scannedClass, genericType));
}
@SuppressWarnings("unchecked")
private static <S, G, P> Supplier<Class<P>> findFirstGenericArgumentTask(final Class<S> scannedClass,
final Class<G> genericType) {
return () -> {
final ParameterizedType augmentationGeneric = findParameterizedType(scannedClass, genericType);
if (augmentationGeneric != null) {
return (Class<P>) augmentationGeneric.getActualTypeArguments()[0];
}
return null;
};
}
public static ParameterizedType findParameterizedType(final Class<?> subclass, final Class<?> genericType) {
Preconditions.checkNotNull(subclass);
Preconditions.checkNotNull(genericType);
for (final Type type : subclass.getGenericInterfaces()) {
if (type instanceof ParameterizedType && genericType.equals(((ParameterizedType) type).getRawType())) {
return (ParameterizedType) type;
}
}
LOG.debug("Class {} does not declare interface {}", subclass, genericType);
return null;
}
public static Type getFirstGenericParameter(final Type type) {
if (type instanceof ParameterizedType) {
return ((ParameterizedType) type).getActualTypeArguments()[0];
}
return null;
}
}