package org.jtheque.utils.bean;

 import org.jtheque.utils.StringUtils;

 import org.slf4j.LoggerFactory;

 import java.beans.BeanInfo;

 import java.beans.IntrospectionException;

 import java.beans.Introspector;

 import java.beans.PropertyDescriptor;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 /*

  * This file is part of JTheque.

  *            

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License. 

  *

  * JTheque 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 Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 /**

  * An utility class for Reflection.

  *

  * @author Baptiste Wicht

  */

 public final class ReflectionUtils {

     private static final PropertyDescriptor[] EMPTY_PROPERTY_DESCRIPTOR_ARRAY = {};

     /**

      * Utility class, not instanciable.

      */

     private ReflectionUtils() {

         super();

     }

     /**

      * Return the name of the getter for the specified property name.

      *

      * @param property The property name.

      * @return The name of the getter for the specified property.

      */

     public static String getGetter(String property) {

         return "get" + StringUtils.setFirstLetterUpper(property);

     }

     /**

      * Return the getter method for the property of the specified bean.

      *

      * @param bean     The bean to get the property from.

      * @param property The property name.

      * @return The getter Method object or null if there is no getter for this property.

      */

     public static Method getGetterMethod(Object bean, String property) {

         try {

             String getter = getGetter(property);

             return bean.getClass().getMethod(getter);

         } catch (NoSuchMethodException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error("The getter doesn't exists", e);

         }

         return null;

     }

     /**

      * Return the name of the setter for the specified property name.

      *

      * @param property The property name.

      *

      * @return The name of the setter for the specified property.

      */

     public static String getSetter(String property) {

         return "set" + StringUtils.setFirstLetterUpper(property);

     }

     /**

      * Return the setter method for the property of the specified bean.

      *

      * @param bean     The bean to set the property to.

      * @param property The property name.

      *

      * @return The setter Method object or null if there is no setter for this property.

      */

     public static Method getSetterMethod(Object bean, String property) {

         String setter = getSetter(property);

         for(Method m : bean.getClass().getMethods()){

             if(m.getName().equals(setter)){

                 return m;

             }

         }

         return null;

     }

     /**

      * Return the value of the property of the specified bean.

      *

      * @param bean     The bean to get the value from.

      * @param property The property name.

      * @return The value of the property or null if there is no getter method.

      */

     public static Object getPropertyValue(Object bean, String property) {

         try {

             Method m = getGetterMethod(bean, property);

             return m.invoke(bean);

         } catch (IllegalAccessException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error("Unable to access the property getter method", e);

         } catch (InvocationTargetException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error("Problem during getter invocation", e);

         }

         return null;

     }

     /**

      * Return the value of a property.

      * <p/>

      * Note : The properties of the Object class are not retrieved.

      *

      * @param bean     The bean to get the property value from.

      * @param property The property.

      * @return the value of the property.

      */

     public static Object getProperty(Object bean, PropertyDescriptor property) {

         Method m = property.getReadMethod();

         Object o = null;

         try {

             o = m.invoke(bean);

         } catch (IllegalAccessException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error(e.getMessage(), e);

         } catch (InvocationTargetException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error(e.getMessage(), e);

         }

         return o;

     }

     /**

      * Return all the properties of a bean. The results are cached using the Introspector class.

      * <p/>

      * Note : The properties of the Object class are not retrieved.

      *

      * @param bean The bean to extract the properties from.

      * @return An array containing all the properties of the bean or an empty array if there was an error during the

      *         property retrieving process.

      */

     public static PropertyDescriptor[] getProperties(Object bean) {

         try {

             BeanInfo info = Introspector.getBeanInfo(bean.getClass(), Object.class);

             return info.getPropertyDescriptors();

         } catch (IntrospectionException e) {

             LoggerFactory.getLogger(ReflectionUtils.class).error("Unable to get the properties", e);

             return EMPTY_PROPERTY_DESCRIPTOR_ARRAY;

         }

     }

     /**

      * Return the value of a property.

      * <p/>

      * Note : The properties of the Object class are not retrieved.

      *

      * @param bean     The bean to get the property value from.

      * @param property The property.

      * @return the value of the property.

      */

     public static Object getProperty(Object bean, String property) {

         for (PropertyDescriptor p : getProperties(bean)) {

             if (p.getName().equals(property)) {

                 return getProperty(bean, p);

             }

         }

         return null;

     }

 }