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/*
 * Copyright (c) 2008-2024, Hazelcast, Inc. All Rights Reserved.
 *
 * 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 com.hazelcast.jet.impl.util;

import com.hazelcast.internal.nio.ClassLoaderUtil;

import javax.annotation.Nullable;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;

import static com.hazelcast.internal.util.ExceptionUtil.sneakyThrow;

public final class ReflectionUtils {

    private ReflectionUtils() {
    }

    /**
     * See {@link ClassLoaderUtil#loadClass(ClassLoader, String)}. Exceptions
     * are sneakily thrown.
     */
    public static  Class loadClass(ClassLoader classLoaderHint, String name) {
        try {
            return ClassLoaderUtil.loadClass(classLoaderHint, name);
        } catch (ClassNotFoundException e) {
            throw sneakyThrow(e);
        }
    }

    /**
     * See {@link ClassLoaderUtil#newInstance(ClassLoader, String)}. Exceptions
     * are sneakily thrown.
     */
    public static  T newInstance(ClassLoader classLoader, String name) {
        try {
            return ClassLoaderUtil.newInstance(classLoader, name);
        } catch (Exception e) {
            throw sneakyThrow(e);
        }
    }

    /**
     * Reads a value of a static field. In case of any exceptions it returns
     * null.
     */
    public static  T readStaticFieldOrNull(String className, String fieldName) {
        try {
            Class clazz = Class.forName(className);
            return readStaticField(clazz, fieldName);
        } catch (ClassNotFoundException | NoSuchFieldException | IllegalAccessException | SecurityException e) {
            return null;
        }
    }

    @SuppressWarnings("unchecked")
    private static  T readStaticField(Class clazz, String fieldName) throws NoSuchFieldException,
            IllegalAccessException {
        Field field = clazz.getDeclaredField(fieldName);
        if (!field.isAccessible()) {
            field.setAccessible(true);
        }
        return (T) field.get(null);
    }

    private static String toPath(String name) {
        return name.replace('.', '/');
    }

    public static String toClassResourceId(String name) {
        return toPath(name) + ".class";
    }

    @Nullable
    public static byte[] getClassContent(String name, ClassLoader classLoader) throws IOException {
        try (InputStream is = classLoader.getResourceAsStream(toClassResourceId(name))) {
            if (is == null) {
                throw new IOException("Resource not found");
            } else {
                return is.readAllBytes();
            }
        }
    }

    /**
     * Finds the value for a static field. If the field doesn't exist, null is returned.
     *
     * @param className name of the class.
     * @param fieldName the name of the static field.
     * @param 
     * @return the value of the static field. If the field doesn't exist, null is returned.
     */
    public static  E findStaticFieldValue(String className, String fieldName) {
        try {
            Class clazz = Class.forName(className);
            Field field = clazz.getField(fieldName);
            return (E) field.get(null);
        } catch (Exception ignore) {
            return null;
        }
    }
}