/***
    * Copyright 2006 Joseph M. Ferner
    * 
    * 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 com.fernsroth.easyio.util;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import com.fernsroth.easyio.exception.GetterNotFoundException;
  import com.fernsroth.easyio.exception.SetterNotFoundException;
  
  /***
   * 
   * @author Joseph M. Ferner (Near Infinity Corporation)
   */
  public final class BeanUtils {
      /***
       * hidden constructor.
       */
      private BeanUtils() {
          // empty
      }
  
      /***
       * gets a named value from an object.
       * @param obj the object to get the value from.
       * @param field the field to set.
       * @return the value of the named field.
       * @throws GetterNotFoundException 
       */
      public static Object getValue(Object obj, Field field)
              throws GetterNotFoundException {
          Class<?> clazz = obj.getClass();
  
          // get getter
          Method method = findGetterMethod(clazz, field.getName());
          try {
              if (method != null) {
                  return method.invoke(obj, new Object[] {});
              } else {
                  return field.get(obj);
              }
          } catch (IllegalArgumentException e) {
              throw new GetterNotFoundException(clazz, field.getName(), e);
          } catch (IllegalAccessException e) {
              throw new GetterNotFoundException(clazz, field.getName(), e);
          } catch (InvocationTargetException e) {
              throw new GetterNotFoundException(clazz, field.getName(), e);
          }
      }
  
      /***
       * finds a getter method in a class.
       * @param clazz the class to get the metter method from.
       * @param name the name of the field.
       * @return the getter method. null, if not found.
       */
      public static Method findGetterMethod(Class<?> clazz, String name) {
          for (Method method : clazz.getMethods()) {
              String methodName = method.getName();
              if (methodName.startsWith("get")) {
                  if (methodName.substring("get".length()).equalsIgnoreCase(name)) {
                      return method;
                  }
              }
          }
          return null;
      }
  
      /***
       * gets a list of all the fields including base classes.
       * @param clazz the class to read.
       * @return the fields.
       */
      public static List<Field> getAllFields(Class<?> clazz) {
          List<Field> fields = new ArrayList<Field>();
          Class<?> superclass = clazz.getSuperclass();
          if (superclass != null && superclass != Object.class) {
              fields.addAll(getAllFields(superclass));
          }
          fields.addAll(Arrays.asList(clazz.getDeclaredFields()));
          return fields;
      }
 
     /***
      * sets a value into an object.
      * @param obj the object to the value into.
      * @param field the field name.
      * @param val the value.
      * @throws SetterNotFoundException  
      */
     public static void setValue(Object obj, Field field, Object val)
             throws SetterNotFoundException {
         Class<?> clazz = obj.getClass();
 
         // get setter
         Method method = findSetterMethod(clazz, field.getName());
         try {
             if (method != null) {
                 method.invoke(obj, new Object[] { val });
             } else {
                 field.set(obj, val);
             }
         } catch (IllegalArgumentException e) {
             throw new SetterNotFoundException(clazz, field.getName(), e);
         } catch (IllegalAccessException e) {
             throw new SetterNotFoundException(clazz, field.getName(), e);
         } catch (InvocationTargetException e) {
             throw new SetterNotFoundException(clazz, field.getName(), e);
         }
     }
 
     /***
      * finds a setter method in the class.
      * @param clazz the class to search.
      * @param name the name of the field.
      * @return the setter method.
      */
     public static Method findSetterMethod(Class<?> clazz, String name) {
         for (Method method : clazz.getMethods()) {
             String methodName = method.getName();
             if (methodName.startsWith("set")) {
                 if (methodName.substring("set".length()).equalsIgnoreCase(name)) {
                     return method;
                 }
             }
         }
         return null;
     }
 
 }