py.una.pol.karaku.log.LogPostProcessor.java Source code

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Here is the source code for py.una.pol.karaku.log.LogPostProcessor.java

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/*-
 * Copyright (c)
 *
 *       2012-2014, Facultad Politcnica, Universidad Nacional de Asuncin.
 *       2012-2014, Facultad de Ciencias Mdicas, Universidad Nacional de Asuncin.
 *       2012-2013, Centro Nacional de Computacin, Universidad Nacional de Asuncin.
 *
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
package py.una.pol.karaku.log;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.ReflectionUtils.FieldCallback;
import org.springframework.util.ReflectionUtils.FieldFilter;
import org.springframework.util.ReflectionUtils.MethodCallback;
import org.springframework.util.ReflectionUtils.MethodFilter;

/**
 * {@link BeanPostProcessor} encargado de inyectar los {@link Logger} a travs
 * de la anotacin {@link Log}.
 * <p>
 * Se utiliza el mtodo {@link #postProcessBeforeInitialization(Object, String)}
 * por que si se utiliza el mtodo
 * {@link #postProcessBeforeInitialization(Object, String)} el objeto recibido
 * ya es un proxy de CGLib
 * </p>
 * 
 * @author Arturo Volpe
 * @since 1.0
 * @version 1.0 Sep 13, 2013
 * @see Log
 */
@Component
public class LogPostProcessor implements BeanPostProcessor {

    private static final Logger LOGGER = LoggerFactory.getLogger(LogPostProcessor.class);

    /**
     * Revisa todos los mtodos o campos que tengan la anotacin {@link Log} y
     * le asigna el valor el Log del bean en cuestin.
     * 
     * <br />
     * 
     * {@inheritDoc}
     * 
     * @param bean
     *            bean a procesar
     * @param beanName
     *            nombre del bean
     * @return el mismo bean
     * @throws BeansException
     *             nunca
     */
    @Override
    public Object postProcessBeforeInitialization(final Object bean, final String beanName) {

        ReflectionUtils.doWithFields(bean.getClass(), new FieldCallback() {

            @Override
            public void doWith(Field field) throws IllegalAccessException {

                if (!Modifier.isFinal(field.getModifiers())) {
                    field.setAccessible(true);
                    Log log = field.getAnnotation(Log.class);
                    field.set(bean, getLogger(bean, log));
                }
            }

        }, new FieldFilter() {

            @Override
            public boolean matches(Field field) {

                return field.getAnnotation(Log.class) != null;
            }
        });

        ReflectionUtils.doWithMethods(bean.getClass(), new MethodCallback() {

            @Override
            public void doWith(Method method) throws IllegalAccessException {

                Log log = method.getAnnotation(Log.class);
                try {
                    method.invoke(bean, getLogger(bean, log));
                } catch (InvocationTargetException e) {
                    LOGGER.warn("Error extracting proxy object from {}", bean.getClass().getName(), e);
                }
            }
        }, new MethodFilter() {

            @Override
            public boolean matches(Method method) {

                return method.getAnnotation(Log.class) != null;

            }
        });

        return bean;

    }

    /**
     * Esta implementacin no hace ninguna accin.
     * 
     * @param bean
     *            bean a procesar
     * @param beanName
     *            nombre del bean
     * @return el mismo bean
     * @throws BeansException
     *             nunca
     */
    @Override
    public Object postProcessAfterInitialization(final Object bean, final String beanName) {

        return bean;
    }

    /**
     * Recupera el {@link Logger} del {@link LoggerFactory} a travs del nombre
     * del log definido en la anotacin o por el nombre de la clase.
     * 
     * @param bean
     * @param log
     * @return {@link Logger}, nunca <code>null</code>.
     */
    private Logger getLogger(final Object bean, Log log) {

        Logger logger;
        if (log.name() == null || "".equals(log.name().trim())) {
            logger = LoggerFactory.getLogger(bean.getClass());
        } else {
            logger = LoggerFactory.getLogger(log.name().trim());
        }
        return logger;
    }
}