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/*
* Artifactural
* Copyright (c) 2018.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation version 2.1
* of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.amadornes.artifactural.gradle;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.function.UnaryOperator;
public class ReflectionUtils {
@SuppressWarnings("unchecked")
public static <T> void alter(Object target, String name, UnaryOperator<T> operator) {
try {
int idx = name.lastIndexOf('.');
if (idx != -1) {
target = drillField(target, name.substring(0, idx));
if (target == null) throw new IllegalStateException("Could not find field '" + name + "'");
name = name.substring(idx + 1);
}
Field f = findField(target.getClass(), name);
if (f == null) throw new IllegalStateException("Could not find '" + name + "'");
T oldV = (T)f.get(target);
T newV = operator.apply(oldV);
f.set(target, newV);
if (f.get(target) != newV) {
throw new IllegalStateException("Failed to set new value on " + f.getDeclaringClass().getName() + "." + f.getName());
}
} catch (IllegalAccessException ex) {
throw new RuntimeException(ex);
}
}
private static Object drillField(Object obj, String path) {
for (String name : path.split("\\.")) {
if (obj == null) return null;
Field f = findField(obj.getClass(), name);
if (f == null) return null;
try {
obj = f.get(obj);
} catch (IllegalAccessException e) {
return null;
}
}
return obj;
}
private static Field findField(Class<?> clazz, String name) {
while (clazz != Object.class) {
for (Field f : clazz.getDeclaredFields()) {
if (f.getName().equals(name)) {
f.setAccessible(true);
if (!definalize(f)) {
System.out.println("Could not definalize field " + f.getDeclaringClass().getName() + "." + f.getName() + " Exception ate, lets see if it works");
}
return f;
}
}
clazz = clazz.getSuperclass();
}
return null;
}
private static Field MODIFIER_ACCESS = null;
private static boolean accessAttempted = false;
private static synchronized boolean definalize(Field f) {
if ((f.getModifiers() & Modifier.FINAL) == 0) {
return true;
}
if (MODIFIER_ACCESS == null && !accessAttempted) {
try {
Field modifiers = Field.class.getDeclaredField("modifiers");
modifiers.setAccessible(true);
MODIFIER_ACCESS = modifiers;
} catch (NoSuchFieldException e) {
System.out.println("Could not access Field.modifiers to definalize reflection object. This happens on JVMs > 12, going to see if things work, if not use JVM 8-11");
}
accessAttempted = true;
}
if (MODIFIER_ACCESS != null) {
try {
MODIFIER_ACCESS.setInt(f, f.getModifiers() & ~Modifier.FINAL);
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new RuntimeException("Could not definalize field " + f.getDeclaringClass().getName() + "." + f.getName(), e);
}
return true;
}
return false;
}
/**
* Invokes a method (can be private).
*/
@SuppressWarnings("unchecked")
public static <T> T invoke(Object target, Class<?> type, String name, Object... args) {
try {
Method method = type.getDeclaredMethod(name);
method.setAccessible(true);
return (T) method.invoke(target, args);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
@SuppressWarnings("unchecked")
public static <T> T get(Object target, String name) {
try {
int idx = name.lastIndexOf('.');
if (idx != -1) {
target = drillField(target, name.substring(0, idx));
if (target == null) throw new IllegalStateException("Could not find field '" + name + "'");
name = name.substring(idx + 1);
}
Field f = findField(target.getClass(), name);
if (f == null) throw new IllegalStateException("Could not find '" + name + "'");
return (T)f.get(target);
} catch (IllegalAccessException ex) {
throw new RuntimeException(ex);
}
}
}
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