net.minecraftforge.fml.relauncher.ReflectionHelper.java Source code

Introduction

Here is the source code for net.minecraftforge.fml.relauncher.ReflectionHelper.java

Source

/*
 * Minecraft Forge
 * Copyright (c) 2016.
 *
 * 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 net.minecraftforge.fml.relauncher;

import com.google.common.base.Preconditions;
import net.minecraft.launchwrapper.Launch;
import org.apache.commons.lang3.StringUtils;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

/**
 * Some reflection helper code.
 *
 * @author cpw
 *
 */
public class ReflectionHelper {
    public static class UnableToFindMethodException extends RuntimeException {
        private static final long serialVersionUID = 1L;
        //private String[] methodNames;

        public UnableToFindMethodException(String[] methodNames, Exception failed) {
            super(failed);
            //this.methodNames = methodNames;
        }

        public UnableToFindMethodException(Throwable failed) {
            super(failed);
        }

    }

    public static class UnableToFindClassException extends RuntimeException {
        private static final long serialVersionUID = 1L;
        //private String[] classNames;

        public UnableToFindClassException(String[] classNames, @Nullable Exception err) {
            super(err);
            //this.classNames = classNames;
        }

    }

    public static class UnableToAccessFieldException extends RuntimeException {
        private static final long serialVersionUID = 1L;
        //private String[] fieldNameList;

        public UnableToAccessFieldException(String[] fieldNames, Exception e) {
            super(e);
            //this.fieldNameList = fieldNames;
        }
    }

    public static class UnableToFindFieldException extends RuntimeException {
        private static final long serialVersionUID = 1L;

        //private String[] fieldNameList;
        public UnableToFindFieldException(String[] fieldNameList, Exception e) {
            super(e);
            //this.fieldNameList = fieldNameList;
        }
    }

    public static Field findField(Class<?> clazz, String... fieldNames) {
        Exception failed = null;
        for (String fieldName : fieldNames) {
            try {
                Field f = clazz.getDeclaredField(fieldName);
                f.setAccessible(true);
                return f;
            } catch (Exception e) {
                failed = e;
            }
        }
        throw new UnableToFindFieldException(fieldNames, failed);
    }

    @SuppressWarnings("unchecked")
    public static <T, E> T getPrivateValue(Class<? super E> classToAccess, @Nullable E instance, int fieldIndex) {
        try {
            Field f = classToAccess.getDeclaredFields()[fieldIndex];
            f.setAccessible(true);
            return (T) f.get(instance);
        } catch (Exception e) {
            throw new UnableToAccessFieldException(new String[0], e);
        }
    }

    @SuppressWarnings("unchecked")
    public static <T, E> T getPrivateValue(Class<? super E> classToAccess, E instance, String... fieldNames) {
        try {
            return (T) findField(classToAccess, fieldNames).get(instance);
        } catch (Exception e) {
            throw new UnableToAccessFieldException(fieldNames, e);
        }
    }

    public static <T, E> void setPrivateValue(Class<? super T> classToAccess, T instance, E value, int fieldIndex) {
        try {
            Field f = classToAccess.getDeclaredFields()[fieldIndex];
            f.setAccessible(true);
            f.set(instance, value);
        } catch (Exception e) {
            throw new UnableToAccessFieldException(new String[0], e);
        }
    }

    public static <T, E> void setPrivateValue(Class<? super T> classToAccess, T instance, E value,
            String... fieldNames) {
        try {
            findField(classToAccess, fieldNames).set(instance, value);
        } catch (Exception e) {
            throw new UnableToAccessFieldException(fieldNames, e);
        }
    }

    @SuppressWarnings("unchecked")
    public static Class<? super Object> getClass(ClassLoader loader, String... classNames) {
        Exception err = null;
        for (String className : classNames) {
            try {
                return (Class<? super Object>) Class.forName(className, false, loader);
            } catch (Exception e) {
                err = e;
            }
        }

        throw new UnableToFindClassException(classNames, err);
    }

    /**
     * Finds a method with the specified name and parameters in the given class and makes it accessible.
     * Note: for performance, store the returned value and avoid calling this repeatedly.
     * <p>
     * Throws an exception if the method is not found.
     *
     * @param clazz          The class to find the method on.
     * @param methodName     The name of the method to find (used in developer environments, i.e. "getWorldTime").
     * @param methodObfName  The obfuscated name of the method to find (used in obfuscated environments, i.e. "getWorldTime").
     *                       If the name you are looking for is on a class that is never obfuscated, this should be null.
     * @param parameterTypes The parameter types of the method to find.
     * @return The method with the specified name and parameters in the given class.
     */
    @Nonnull
    public static Method findMethod(@Nonnull Class<?> clazz, @Nonnull String methodName,
            @Nullable String methodObfName, Class<?>... parameterTypes) {
        Preconditions.checkNotNull(clazz);
        Preconditions.checkArgument(StringUtils.isNotEmpty(methodName), "Method name cannot be empty");

        String nameToFind;
        if (methodObfName == null || (Boolean) Launch.blackboard.get("fml.deobfuscatedEnvironment")) {
            nameToFind = methodName;
        } else {
            nameToFind = methodObfName;
        }

        try {
            Method m = clazz.getDeclaredMethod(nameToFind, parameterTypes);
            m.setAccessible(true);
            return m;
        } catch (Exception e) {
            throw new UnableToFindMethodException(e);
        }
    }
}