// Spring低级JavaBeans基础设施的中央接口。通常来说并不直接使用BeanWrapper，而是借助BeanFactory或者DataBinder来一起使用,BeanWrapper对Spring中的Bean做了包装，为的是更加方便的操作Bean中的属性
public interface BeanWrapper extends ConfigurablePropertyAccessor {
  void setAutoGrowCollectionLimit(int autoGrowCollectionLimit);
  int getAutoGrowCollectionLimit();
  // 获取包装的Bean
  Object getWrappedInstance();
  // 获取包装的Bean的class
  Class<?> getWrappedClass();
  // 获取所有属性的属性描述符
  PropertyDescriptor[] getPropertyDescriptors();
  // 获取指定属性的属性描述符
  PropertyDescriptor getPropertyDescriptor(String propertyName) throws InvalidPropertyException;
}

// 这个接口的功能很简单，就是用来注入属性编辑器（PropertyEditor），那么什么是PropertyEditor呢？
public interface PropertyEditorRegistry {
  void registerCustomEditor(Class<?> requiredType, PropertyEditor propertyEditor);
  void registerCustomEditor(@Nullable Class<?> requiredType, @Nullable String propertyPath, PropertyEditor propertyEditor);
  @Nullable
  PropertyEditor findCustomEditor(@Nullable Class<?> requiredType, @Nullable String propertyPath);
}

public interface PropertyAccessor {
    // 嵌套属性的分隔符,比如"foo.bar"将会调用getFoo().getBar()两个方法
  String NESTED_PROPERTY_SEPARATOR = ".";
  char NESTED_PROPERTY_SEPARATOR_CHAR = '.';
   // 代表角标index的符号  如person.addresses[0]  这样就可以把值放进集合/数组/Map里了
  String PROPERTY_KEY_PREFIX = "[";
  char PROPERTY_KEY_PREFIX_CHAR = '[';
  String PROPERTY_KEY_SUFFIX = "]";
  char PROPERTY_KEY_SUFFIX_CHAR = ']';
    // 该属性是否可读/可写，不存在则返回false
  boolean isReadableProperty(String propertyName);
  boolean isWritableProperty(String propertyName);
    // 获取/设置属性的方法，基本见名知意
  @Nullable
  Class<?> getPropertyType(String propertyName) throws BeansException;
  @Nullable
  TypeDescriptor getPropertyTypeDescriptor(String propertyName) throws BeansException;
  @Nullable
  Object getPropertyValue(String propertyName) throws BeansException;
  void setPropertyValue(String propertyName, @Nullable Object value) throws BeansException;
  void setPropertyValue(PropertyValue pv) throws BeansException;
  void setPropertyValues(Map<?, ?> map) throws BeansException;
  void setPropertyValues(PropertyValues pvs) throws BeansException;
  void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown)
      throws BeansException;
  void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown, boolean ignoreInvalid)
      throws BeansException;
}

// 定义了进行类型转换时的一些规范，就像名字定义的那样，主要用来做类型转换
public interface TypeConverter {
    // 将指定的值转换成指定的类型
  @Nullable
  <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType) throws TypeMismatchException;
    // 相对于上面这个方法下面这个三种方法能处理转换过程中的泛型
  @Nullable
  <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType,
      @Nullable MethodParameter methodParam) throws TypeMismatchException;
  @Nullable
  <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType, @Nullable Field field)
      throws TypeMismatchException;
  default <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType,
      @Nullable TypeDescriptor typeDescriptor) throws TypeMismatchException {
    throw new UnsupportedOperationException("TypeDescriptor resolution not supported");
  }
}

public interface ConfigurablePropertyAccessor extends PropertyAccessor, PropertyEditorRegistry, TypeConverter {
  // ConversionService：进行转换的业务类，转换系统的入口
  void setConversionService(@Nullable ConversionService conversionService);
  @Nullable
  ConversionService getConversionService();
    // 进行属性编辑是是否返回旧的值
  void setExtractOldValueForEditor(boolean extractOldValueForEditor);
  boolean isExtractOldValueForEditor();
    // 当设置（dog.name）这种嵌套属性的情况下，如果dog属性为null是否会报错
    // 为true的话不会，为false会抛出NullValueInNestedPathException
  void setAutoGrowNestedPaths(boolean autoGrowNestedPaths);
  boolean isAutoGrowNestedPaths();
}