org.ngrinder.common.util.ReflectionUtil.java Source code

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Here is the source code for org.ngrinder.common.util.ReflectionUtil.java

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/* 
 * 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.ngrinder.common.util;

import static org.ngrinder.common.util.NoOp.noOp;
import static org.ngrinder.common.util.Preconditions.checkArgument;
import static org.ngrinder.common.util.Preconditions.checkNotNull;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Reflection Utility functions.
 * 
 * @author JunHo Yoon
 * @since 3.0
 */
public abstract class ReflectionUtil {

    private static final Logger LOG = LoggerFactory.getLogger(ReflectionUtil.class);

    /**
     * get object field value, bypassing getter method.
     * 
     * @param object
     *            object
     * @param fieldName
     *            field Name
     * @return fileValue
     */
    public static Object getFieldValue(final Object object, final String fieldName) {
        Field field = getDeclaredField(object, fieldName);
        checkNotNull(field, "Could not find field [%s] on target [%s]", fieldName, object);
        makeAccessible(field);

        try {
            return field.get(object);
        } catch (IllegalAccessException e) {
            LOG.error(e.getMessage(), e);
        }
        return null;
    }

    private static Field getDeclaredField(final Object object, final String fieldName) {
        checkNotNull(object);
        checkArgument(StringUtils.isNotBlank(fieldName));

        // CHECKSTYLE:OFF
        for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
                .getSuperclass()) {
            try {
                return superClass.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                // Fall through
                noOp();
            }
        }
        return null;
    }

    private static void makeAccessible(final Field field) {
        if (!Modifier.isPublic(field.getModifiers())
                || !Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
            field.setAccessible(true);
        }
    }

    @SuppressWarnings("unchecked")
    public static <T> T newInstanceByName(String className)
            throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        Class<?> loader = Class.forName(className);
        return (T) loader.newInstance();
    }
}