Class template basic_custom

Class template basic_custom_mapping

boost::log::sinks::basic_custom_mapping — Customizable mapping.

Synopsis

// In header: <boost/log/sinks/attribute_mapping.hpp>

template<typename CharT, typename MappedT, typename AttributeValueT = int> 
class basic_custom_mapping :
  public boost::log::sinks::basic_mapping< CharT, MappedT >
{
public:
  // types
  typedef AttributeValueT             attribute_value_type;  // Attribute contained value type. 
  typedef base_type::char_type        char_type;             // Char type. 
  typedef base_type::string_type      string_type;           // String type. 
  typedef base_type::values_view_type values_view_type;      // Attribute values view type. 
  typedef base_type::mapped_type      mapped_type;           // Mapped value type. 

  // construct/copy/destruct
  explicit basic_custom_mapping(string_type const &, mapped_type const &);

  // public member functions
  mapped_type operator()(values_view_type const &) const;
  implementation_defined operator[](attribute_value_type const &);
};

Description

The class allows to setup a custom mapping between an attribute and native values. The mapping should be initialized similarly to the standard map container, by using indexing operator and assignment.

	Note
	Unlike many other components of the library, exact type of the attribute value must be specified in the template parameter `AttributeValueT`. Type sequences are not supported.

`basic_custom_mapping` public construct/copy/destruct

explicit basic_custom_mapping(string_type const & name, 
                              mapped_type const & default_value);

Constructor

Parameters:

`default_value`	The default native value that is returned if the conversion cannot be performed
`name`	Attribute name

`basic_custom_mapping` public member functions

```
mapped_type operator()(values_view_type const & values) const;
```
Extraction operator. Extracts the attribute value and attempts to map it onto the native value.

Parameters:

values
A set of attribute values attached to a logging record

Returns:
A mapped value, if mapping was successfull, or the default value if mapping did not succeed.

implementation_defined operator[](attribute_value_type const & key);

Insertion operator

Parameters:

key

Attribute value to be mapped

Returns:

An object of unspecified type that allows to insert a new mapping through assignment. The key argument becomes the key attribute value, and the assigned value becomes the mapped native value.