org.mqnaas.general.test.helpers.reflection.ReflectionTestHelper.java Source code

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Here is the source code for org.mqnaas.general.test.helpers.reflection.ReflectionTestHelper.java

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package org.mqnaas.general.test.helpers.reflection;

/*
 * #%L
 * MQNaaS :: General Test Helpers
 * %%
 * Copyright (C) 2007 - 2015 Fundaci Privada i2CAT, Internet i Innovaci a Catalunya
 * %%
 * This program 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, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program 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 General Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/lgpl-3.0.html>.
 * #L%
 */

import java.lang.reflect.Field;
import java.util.List;

import org.apache.commons.lang3.ClassUtils;

/**
 * Reflection Test Helpers
 * 
 * @author Julio Carlos Barrera
 *
 */
public class ReflectionTestHelper {

    /**
     * Injects a private {@link Field} fieldInstance (instance of F) into classInstance (instance of T). It uses fieldName to look for private field.
     * 
     * @param classInstance
     *            target instance
     * @param fieldInstance
     *            field instance to be injected
     * @param fieldName
     *            target field name
     * @throws SecurityException
     *             if this exception is thrown during the process
     * @throws IllegalArgumentException
     *             if fieldName could not be found in classInstance {@link Class} or if fieldInstance is not a compatible type to be injected
     * @throws IllegalAccessException
     *             if this exception is thrown during the process
     */
    public static <T, F> void injectPrivateField(T classInstance, F fieldInstance, String fieldName)
            throws SecurityException, IllegalArgumentException, IllegalAccessException {

        // get all super classes and add itself
        List<Class<?>> classes = ClassUtils.getAllSuperclasses(classInstance.getClass());
        classes.add(classInstance.getClass());

        for (Class<?> clazz : classes) {

            Field field;
            try {
                field = clazz.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                // try next class
                continue;
            }
            if (!field.getType().isAssignableFrom(fieldInstance.getClass())) {
                throw new IllegalArgumentException(
                        "Invalid fieldName received, fieldInstance can not assigned to field.");
            }

            field.setAccessible(true);
            field.set(classInstance, fieldInstance);
            field.setAccessible(false);
            return;

        }

        throw new IllegalArgumentException(
                "Invalid fieldName received, a field with this name can not be found in this class or its superclasses.");
    }

}