/*
    * Copyright 2007-2012 the original author or authors.
    *
    * 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.springbyexample.util.log;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Field;
  import java.lang.reflect.Method;
  import java.lang.reflect.Modifier;
  
  import org.springframework.util.Assert;
  import org.springframework.util.ReflectionUtils;
  
  /**
   * <p>Injects loggers into new bean instances based on   
   * fields marked with {@link AutowiredLogger} annotation.</p>
   * 
   * @author David Winterfeldt
   */
  public class AnnotationLoggerBeanPostProcessor extends LoggerBeanPostProcessor {
  
      private Class<? extends Annotation> autowiredAnnotationType = AutowiredLogger.class;
      
      /**
       * Gets autowired logger annotation type.
       * Defaults to <code>AutowiredLogger</code>.
       */
      protected Class<? extends Annotation> getAutowiredAnnotationType() {
          return this.autowiredAnnotationType;
      }
  
      /**
       * Sets autowired logger annotation type.
       * Defaults to <code>AutowiredLogger</code>.
       */
      public void setAutowiredAnnotationType(Class<? extends Annotation> autowiredAnnotationType) {
          Assert.notNull(autowiredAnnotationType, "Autowired logger annotation type must not be null.");
          this.autowiredAnnotationType = autowiredAnnotationType;
      }
  
      /**
       * <p>Processes a beans fields for injection if it has a {@link AutowiredLogger} annotation.</p>
       * 
       * <p><strong>Note</strong>: Method name isn't used by this implementation.</p>
       */
      protected void processLogger(final Object bean, final String methodName) {
          // FIX ME: cache a classes inject data?
          
          final Class<?> clazz = bean.getClass();
  
          ReflectionUtils.doWithFields(clazz, new ReflectionUtils.FieldCallback() {
              public void doWith(Field field) {
                  Annotation annotation = field.getAnnotation(getAutowiredAnnotationType());
                  
                  if (annotation != null) {
                      if (Modifier.isStatic(field.getModifiers())) {
                          throw new IllegalStateException("Autowired annotation is not supported on static fields");
                      }
                      
                      ReflectionUtils.makeAccessible(field);
                      
                      Object logger = getLogger(bean.getClass().getName(),
                                                field.getType().getName());
                      
                      ReflectionUtils.setField(field, bean, logger);
                  }
              }
          });
          
          ReflectionUtils.doWithMethods(clazz, new ReflectionUtils.MethodCallback() {
              public void doWith(Method method) {
                  Annotation annotation = method.getAnnotation(getAutowiredAnnotationType());
                  
                  if (annotation != null) {
                      if (Modifier.isStatic(method.getModifiers())) {
                          throw new IllegalStateException("Autowired logger annotation is not supported on static methods");
                      }
                      
                      if (method.getParameterTypes().length == 0) {
                          throw new IllegalStateException("Autowired logger annotation requires at least one argument: " + method);
                      }
                      
                      injectMethod(bean, method);
                  }
              }
          });
     }
 
 }