/*
* This file is part of LanternServer, licensed under the MIT License (MIT).
*
* Copyright (c) LanternPowered <https://www.lanternpowered.org>
* Copyright (c) SpongePowered <https://www.spongepowered.org>
* Copyright (c) contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the Software), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.lanternpowered.server.util;
import static com.google.common.base.Preconditions.checkArgument;
import static org.apache.commons.lang3.ClassUtils.isAssignable;
import com.google.common.base.Throwables;
import org.lanternpowered.server.game.Lantern;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.annotation.Nullable;
public final class ReflectionHelper {
private final static Field MODIFIERS_FIELD;
static {
try {
MODIFIERS_FIELD = Field.class.getDeclaredField("modifiers");
MODIFIERS_FIELD.setAccessible(true);
} catch (NoSuchFieldException e) {
throw Throwables.propagate(e);
}
}
public static void setField(Field field, @Nullable Object target, @Nullable Object object) throws Exception {
final int modifiers = field.getModifiers();
if (Modifier.isFinal(modifiers)) {
MODIFIERS_FIELD.set(field, modifiers & ~Modifier.FINAL);
}
field.setAccessible(true);
field.set(target, object);
}
public static <T> T createUnsafeInstance(final Class<T> objectClass, @Nullable Object... args)
throws IllegalAccessException, InvocationTargetException, InstantiationException {
if (args == null) {
args = new Object[] { null };
}
final Constructor<T>tConstructor = findConstructor(objectClass, args);
try {
return tConstructor.newInstance(args);
} catch (Exception e) {
final Object[] deconstructedArgs = deconstructArray(args).toArray();
return tConstructor.newInstance(deconstructedArgs);
}
}
public static <T> T createInstance(final Class<T> objectClass, @Nullable Object... args) {
checkArgument(!Modifier.isAbstract(objectClass.getModifiers()), "Cannot construct an instance of an abstract class!");
checkArgument(!Modifier.isInterface(objectClass.getModifiers()), "Cannot construct an instance of an interface!");
if (args == null) {
args = new Object[] { null };
}
final Constructor<T> ctor = findConstructor(objectClass, args);
try {
return ctor.newInstance(args);
} catch (InstantiationException | IllegalAccessException | InvocationTargetException e) {
Lantern.getLogger().error("Couldn't find an appropriate constructor for " + objectClass.getCanonicalName()
+ "with the args: " + Arrays.toString(args), e);
}
throw new IllegalArgumentException("Couldn't find an appropriate constructor for " + objectClass.getCanonicalName()
+ "the args: " + Arrays.toString(args));
}
@SuppressWarnings("unchecked")
public static <T> Constructor<T> findConstructor(final Class<T> objectClass, @Nullable Object... args) {
final Constructor<?>[] ctors = objectClass.getConstructors();
if (args == null) {
args = new Object[] {null};
}
// labeled loops
dance:
for (final Constructor<?> ctor : ctors) {
final Class<?>[] paramTypes = ctor.getParameterTypes();
if (paramTypes.length != args.length) {
for (Object object : args) {
if (object != null) { // hahahah
if (object.getClass().isArray()) {
final Object[] objects = deconstructArray(args).toArray();
return findConstructor(objectClass, objects);
}
}
}
continue; // we haven't found the right constructor
}
for (int i = 0; i < paramTypes.length; i++) {
final Class<?> parameter = paramTypes[i];
if (!isAssignable(args[i] == null ? null : args[i].getClass(), parameter, true)) {
continue dance; // continue the outer loop since we didn't find the right one
}
}
// We've found the right constructor, now to actually construct it!
return (Constructor<T>) ctor;
}
throw new IllegalArgumentException("Applicable constructor not found for class: " + objectClass.getCanonicalName() +
" with args: " + Arrays.toString(args));
}
private static List<Object> deconstructArray(Object[] objects) {
final List<Object> list = new ArrayList<>();
for (Object object : objects) {
if (object == null) {
list.add(null);
continue;
}
if (object.getClass().isArray()) {
list.addAll(deconstructArray((Object[]) object));
} else {
list.add(object);
}
}
return list;
}
private ReflectionHelper() {
}
}