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/*
 * Copyright 2013-2015 the original author or authors.
 *
 * Licensed 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.glowroot.common;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

import javax.annotation.Nullable;

import org.glowroot.shaded.slf4j.Logger;
import org.glowroot.shaded.slf4j.LoggerFactory;

public class Reflections {

    private static final Logger logger = LoggerFactory.getLogger(Reflections.class);

    private Reflections() {}

    public static Method getMethod(Class clazz, String name, Class... parameterTypes)
            throws Exception {
        Method method = clazz.getMethod(name, parameterTypes);
        method.setAccessible(true);
        return method;
    }

    public static Method getDeclaredMethod(Class clazz, String name, Class... parameterTypes)
            throws Exception {
        Method method = clazz.getDeclaredMethod(name, parameterTypes);
        method.setAccessible(true);
        return method;
    }

    public static Method getAnyMethod(Class clazz, String name, Class... parameterTypes)
            throws Exception {
        try {
            return getMethod(clazz, name, parameterTypes);
        } catch (NoSuchMethodException e) {
            // log exception at trace level
            logger.trace(e.getMessage(), e);
            return getAnyDeclaredMethod(clazz, name, parameterTypes);
        }
    }

    private static Method getAnyDeclaredMethod(Class clazz, String name,
            Class... parameterTypes) throws Exception {
        try {
            Method method = clazz.getDeclaredMethod(name, parameterTypes);
            method.setAccessible(true);
            return method;
        } catch (NoSuchMethodException e) {
            // log exception at trace level
            logger.trace(e.getMessage(), e);
            Class superClass = clazz.getSuperclass();
            if (superClass == null) {
                throw e;
            }
            return getAnyDeclaredMethod(superClass, name, parameterTypes);
        }
    }

    public static  Constructor getConstructor(Class clazz, Class... parameterTypes)
            throws Exception {
        Constructor constructor = clazz.getConstructor(parameterTypes);
        constructor.setAccessible(true);
        return constructor;
    }

    public static Field getAnyField(Class clazz, String fieldName) throws Exception {
        try {
            Field field = clazz.getField(fieldName);
            field.setAccessible(true);
            return field;
        } catch (NoSuchFieldException e) {
            // log exception at trace level
            logger.trace(e.getMessage(), e);
            return getAnyDeclaredField(clazz, fieldName);
        }
    }

    private static Field getAnyDeclaredField(Class clazz, String fieldName) throws Exception {
        try {
            Field field = clazz.getDeclaredField(fieldName);
            field.setAccessible(true);
            return field;
        } catch (NoSuchFieldException e) {
            // log exception at trace level
            logger.trace(e.getMessage(), e);
            Class superClass = clazz.getSuperclass();
            if (superClass == null) {
                throw e;
            }
            return getAnyDeclaredField(superClass, fieldName);
        }
    }

    public static @Nullable Object invoke(Method method, Object obj, @Nullable Object... args)
            throws Exception {
        return method.invoke(obj, args);
    }

    public static @Nullable Object invokeStatic(Method method, @Nullable Object... args)
            throws Exception {
        return method.invoke(null, args);
    }

    public static  /*@NonNull*/T invoke(Constructor constructor, @Nullable Object... args)
            throws Exception {
        return constructor.newInstance(args);
    }

    public static @Nullable Object getFieldValue(Field field, Object obj) throws Exception {
        return field.get(obj);
    }
}