org.springframework.beans

## Interface BeanWrapper

- All Superinterfaces:
    ConfigurablePropertyAccessor, PropertyAccessor, PropertyEditorRegistry, TypeConverter
  All Known Implementing Classes:
    BeanWrapperImpl

      public interface BeanWrapper
      extends ConfigurablePropertyAccessor

  The central interface of Spring's low-level JavaBeans infrastructure.

  Typically not used directly but rather implicitly via a `BeanFactory` or a `DataBinder`.

  Provides operations to analyze and manipulate standard JavaBeans: the ability to get and set property values (individually or in bulk), get property descriptors, and query the readability/writability of properties.

  This interface supports nested properties enabling the setting of properties on subproperties to an unlimited depth.

  A BeanWrapper's default for the "extractOldValueForEditor" setting is "false", to avoid side effects caused by getter method invocations. Turn this to "true" to expose present property values to custom editors.

  Since:
    13 April 2001
  Author:
    Rod Johnson, Juergen Hoeller
  See Also:
    `PropertyAccessor`, `PropertyEditorRegistry`, `PropertyAccessorFactory.forBeanPropertyAccess(java.lang.Object)`, `BeanFactory`, `BeanPropertyBindingResult`, `DataBinder.initBeanPropertyAccess()`

- - ### Field Summary

    - ### Fields inherited from interface org.springframework.beans.PropertyAccessor

      `NESTED_PROPERTY_SEPARATOR, NESTED_PROPERTY_SEPARATOR_CHAR, PROPERTY_KEY_PREFIX, PROPERTY_KEY_PREFIX_CHAR, PROPERTY_KEY_SUFFIX, PROPERTY_KEY_SUFFIX_CHAR`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `getAutoGrowCollectionLimit()` Return the limit for array and collection auto-growing.
    `PropertyDescriptor` | `getPropertyDescriptor(String propertyName)` Obtain the property descriptor for a specific property of the wrapped object.
    `PropertyDescriptor[]` | `getPropertyDescriptors()` Obtain the PropertyDescriptors for the wrapped object (as determined by standard JavaBeans introspection).
    `Class` | `getWrappedClass()` Return the type of the wrapped JavaBean object.
    `Object` | `getWrappedInstance()` Return the bean instance wrapped by this object, if any.
    `boolean` | `isAutoGrowNestedPaths()` Return whether "auto-growing" of nested paths has been activated.
    `void` | `setAutoGrowCollectionLimit(int autoGrowCollectionLimit)` Specify a limit for array and collection auto-growing.
    `void` | `setAutoGrowNestedPaths(boolean autoGrowNestedPaths)` Set whether this BeanWrapper should attempt to "auto-grow" a nested path that contains a null value.

    - ### Methods inherited from interface org.springframework.beans.ConfigurablePropertyAccessor

      `getConversionService, isExtractOldValueForEditor, setConversionService, setExtractOldValueForEditor`

    - ### Methods inherited from interface org.springframework.beans.PropertyAccessor

      `getPropertyType, getPropertyTypeDescriptor, getPropertyValue, isReadableProperty, isWritableProperty, setPropertyValue, setPropertyValue, setPropertyValues, setPropertyValues, setPropertyValues, setPropertyValues`

    - ### Methods inherited from interface org.springframework.beans.PropertyEditorRegistry

      `findCustomEditor, registerCustomEditor, registerCustomEditor`

    - ### Methods inherited from interface org.springframework.beans.TypeConverter

      `convertIfNecessary, convertIfNecessary, convertIfNecessary`

- - ### Method Detail

    - #### getWrappedInstance

          Object getWrappedInstance()

      Return the bean instance wrapped by this object, if any.
      Returns:
        the bean instance, or `null` if none set

    - #### getWrappedClass

          Class getWrappedClass()

      Return the type of the wrapped JavaBean object.
      Returns:
        the type of the wrapped bean instance, or `null` if no wrapped object has been set

    - #### getPropertyDescriptors

          PropertyDescriptor[] getPropertyDescriptors()

      Obtain the PropertyDescriptors for the wrapped object (as determined by standard JavaBeans introspection).
      Returns:
        the PropertyDescriptors for the wrapped object

    - #### getPropertyDescriptor

          PropertyDescriptor getPropertyDescriptor(String propertyName)
                                                   throws InvalidPropertyException

      Obtain the property descriptor for a specific property of the wrapped object.
      Parameters:
        `propertyName` - the property to obtain the descriptor for (may be a nested path, but no indexed/mapped property)
      Returns:
        the property descriptor for the specified property
      Throws:
        `InvalidPropertyException` - if there is no such property

    - #### setAutoGrowNestedPaths

          void setAutoGrowNestedPaths(boolean autoGrowNestedPaths)

      Set whether this BeanWrapper should attempt to "auto-grow" a nested path that contains a null value.

      If "true", a null path location will be populated with a default object value and traversed instead of resulting in a `NullValueInNestedPathException`. Turning this flag on also enables auto-growth of collection elements when accessing an out-of-bounds index.

      Default is "false" on a plain BeanWrapper.

    - #### isAutoGrowNestedPaths

          boolean isAutoGrowNestedPaths()

      Return whether "auto-growing" of nested paths has been activated.

    - #### setAutoGrowCollectionLimit

          void setAutoGrowCollectionLimit(int autoGrowCollectionLimit)

      Specify a limit for array and collection auto-growing.

      Default is unlimited on a plain BeanWrapper.

    - #### getAutoGrowCollectionLimit

          int getAutoGrowCollectionLimit()

      Return the limit for array and collection auto-growing.