foundation/org.eclipse.persistence.core.test.framework/src/main/java/org/eclipse/persistence/testing/framework/ReflectionHelper.java

/*
 * Copyright (c) 2015, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     05/14/2015-2.7 Tomas Kraus
//       - Initial API and implementation.
package org.eclipse.persistence.testing.framework;

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

/**
 * Reflection helper methods.
 */
public class ReflectionHelper {

    /**
     * Set value of private static field.
     * @param c        Class containing static field.
     * @param name     Static field name to be modified.
     * @param newValue New value to be set.
     * @throws NoSuchFieldException If a field with the specified name is not found.
     * @throws SecurityException If a security manager is present and access to the field was denied.
     * @throws IllegalArgumentException If an unwrapping conversion fails.
     * @throws IllegalAccessException If the underlying field is either inaccessible or final.
     */
    public static final void setPrivateStatic(final Class<?> c, final String name, final Object newValue)
            throws ReflectiveOperationException {
        final Field field = c.getDeclaredField(name);
        final boolean accessible = field.isAccessible();
        field.setAccessible(true);
        field.set(null, newValue);
        field.setAccessible(accessible);
     }

    /**
     * Get value of private static field.
     * @param c    Class containing static field.
     * @param name Static field name to be retrieved.
     * @return Static field value.
     * @throws NoSuchFieldException If a field with the specified name is not found.
     * @throws SecurityException If a security manager is present and access to the field was denied.
     * @throws IllegalArgumentException If an unwrapping conversion fails.
     * @throws IllegalAccessException If the underlying field is either inaccessible or final.
     */
    public static final <T> T getPrivateStatic(final Class<?> c, final String name)
            throws ReflectiveOperationException {
        final Field field = c.getDeclaredField(name);
        final boolean accessible = field.isAccessible();
        field.setAccessible(true);
        final Object value = field.get(null);
        field.setAccessible(accessible);
        return (T)value;
     }

    /**
     * Create a new instance of the specified class.
     * @param c Class containing constructor.
     * @param parameterTypes Constructor parameter array.
     * @param args An array of objects to be passed as arguments to the constructor call
     * @throws InvocationTargetException If the underlying constructor throws an exception.
     * @throws IllegalArgumentException  If an unwrapping conversion fails.
     * @throws IllegalAccessException    If the underlying field is either inaccessible or final.
     * @throws InstantiationException    If the class that declares the underlying constructor represents
     *                                   an abstract class.
     * @throws SecurityException         If a security manager is present and access to the field was denied.
     * @throws NoSuchMethodException     If a field with the specified name is not found.
     */
    public static final <T> T getInstance(final Class<T> c, final Class<?>[] parameterTypes, final Object... args)
            throws ReflectiveOperationException {
        Constructor<T> co = c.getDeclaredConstructor(parameterTypes);
        return co.newInstance(args);
    }

    /**
     * Invoke a method of the specified class instance.
     * @param name Method name.
     * @param obj Class instance containing method to invoke.
     * @param parameterTypes Method parameter array.
     * @param args An array of objects to be passed as arguments to the method call
     * @throws InvocationTargetException If the underlying constructor throws an exception.
     * @throws IllegalArgumentException  If an unwrapping conversion fails.
     * @throws IllegalAccessException    If the underlying field is either inaccessible or final.
     * @throws SecurityException         If a security manager is present and access to the field was denied.
     * @throws NoSuchMethodException     If a field with the specified name is not found.
     */
    public static final Object invokeMethod(
            final String name, final Object obj, final Class<?>[] parameterTypes, final Object... args)
            throws ReflectiveOperationException {
        Method m = obj.getClass().getDeclaredMethod(name, parameterTypes);
        boolean accessible = m.isAccessible();
        if (!accessible) {
            m.setAccessible(true);
        }
        Object result = m.invoke(obj, args);
        if (!accessible) {
            m.setAccessible(accessible);
        }
        return result;
    }

    /**
     * Invoke a method of the specified class instance.
     * @param name Method name.
     * @param obj Class instance containing method to invoke.
     * @param parameterTypes Method parameter array.
     * @param returnType Class to be returned.
     * @param args An array of objects to be passed as arguments to the method call
     * @throws InvocationTargetException If the underlying constructor throws an exception.
     * @throws IllegalArgumentException  If an unwrapping conversion fails.
     * @throws IllegalAccessException    If the underlying field is either inaccessible or final.
     * @throws SecurityException         If a security manager is present and access to the field was denied.
     * @throws NoSuchMethodException     If a field with the specified name is not found.
     */
    public static final <T> T invokeMethod(
            final String name, final Object obj, final Class<?>[] parameterTypes, final Class<T> returnType, final Object... args)
            throws ReflectiveOperationException {
        return returnType.cast(invokeMethod(name, obj, parameterTypes, args));
    }

    /**
     * Invoke static method of the specified class.
     * @param name Method name.
     * @param c Class containing method to invoke.
     * @param parameterTypes Method parameter array.
     * @param args An array of objects to be passed as arguments to the method call
     * @throws InvocationTargetException If the underlying constructor throws an exception.
     * @throws IllegalArgumentException  If an unwrapping conversion fails.
     * @throws IllegalAccessException    If the underlying field is either inaccessible or final.
     * @throws SecurityException         If a security manager is present and access to the field was denied.
     * @throws NoSuchMethodException     If a field with the specified name is not found.
     */
    public static final Object invokeStaticMethod(
            final String name, final Class<?> c, final Class<?>[] parameterTypes, final Object... args)
            throws ReflectiveOperationException {
        Method m = c.getDeclaredMethod(name, parameterTypes);
        boolean accessible = m.isAccessible();
        if (!accessible) {
            m.setAccessible(true);
        }
        Object result = m.invoke(null, args);
        if (!accessible) {
            m.setAccessible(accessible);
        }
        return result;
    }

    /**
     * Invoke static method of the specified class.
     * @param name Method name.
     * @param c Class containing method to invoke.
     * @param parameterTypes Method parameter array.
     * @param returnType Class to be returned.
     * @param args An array of objects to be passed as arguments to the method call
     * @throws InvocationTargetException If the underlying constructor throws an exception.
     * @throws IllegalArgumentException  If an unwrapping conversion fails.
     * @throws IllegalAccessException    If the underlying field is either inaccessible or final.
     * @throws SecurityException         If a security manager is present and access to the field was denied.
     * @throws NoSuchMethodException     If a field with the specified name is not found.
     */
    public static final <T> T invokeStaticMethod(
            final String name, final Class<?> c, final Class<?>[] parameterTypes, final Class<T> returnType, final Object... args)
            throws ReflectiveOperationException {
        return returnType.cast(invokeStaticMethod(name, c, parameterTypes, args));
    }

}