Package org.mapstruct

Annotation Type ValueMapping

  • @Repeatable(ValueMappings.class)
@Retention(CLASS)
@Target({METHOD,ANNOTATION_TYPE})
public @interface ValueMapping
    Configures the mapping of source constant value to target constant value.

    Supported mappings are

    1. Enumeration to Enumeration
    Example 1: 
    
 public enum OrderType { RETAIL, B2B, C2C, EXTRA, STANDARD, NORMAL }

 public enum ExternalOrderType { RETAIL, B2B, SPECIAL, DEFAULT }

 @ValueMapping(target = "SPECIAL", source = "EXTRA"),
 @ValueMapping(target = "DEFAULT", source = "STANDARD"),
 @ValueMapping(target = "DEFAULT", source = "NORMAL")
 ExternalOrderType orderTypeToExternalOrderType(OrderType orderType);
 
 Mapping result:
 +---------------------+----------------------------+
 | OrderType           | ExternalOrderType          |
 +---------------------+----------------------------+
 | null                | null                       |
 | OrderType.EXTRA     | ExternalOrderType.SPECIAL  |
 | OrderType.STANDARD  | ExternalOrderType.DEFAULT  |
 | OrderType.NORMAL    | ExternalOrderType.DEFAULT  |
 | OrderType.RETAIL    | ExternalOrderType.RETAIL   |
 | OrderType.B2B       | ExternalOrderType.B2B      |
 +---------------------+----------------------------+
    Example 2: 
    
 @ValueMapping( source = MappingConstants.NULL, target = "DEFAULT" ),
 @ValueMapping( source = "STANDARD", target = MappingConstants.NULL ),
 @ValueMapping( source = MappingConstants.ANY_REMAINING, target = "SPECIAL" )
 ExternalOrderType orderTypeToExternalOrderType(OrderType orderType);
 
 Mapping result:
 +---------------------+----------------------------+
 | OrderType           | ExternalOrderType          |
 +---------------------+----------------------------+
 | null                | ExternalOrderType.DEFAULT  |
 | OrderType.STANDARD  | null                       |
 | OrderType.RETAIL    | ExternalOrderType.RETAIL   |
 | OrderType.B2B       | ExternalOrderType.B2B      |
 | OrderType.NORMAL    | ExternalOrderType.SPECIAL  |
 | OrderType.EXTRA     | ExternalOrderType.SPECIAL  |
 +---------------------+----------------------------+
    Example 3: MapStruct will WARN on incomplete mappings. However, if for some reason no match is found, an IllegalStateException will be thrown. This compile-time error can be avoided by using MappingConstants.THROW_EXCEPTION for target(). It will result an IllegalArgumentException at runtime. 
    
 @ValueMapping( source = "STANDARD", target = "DEFAULT" ),
 @ValueMapping( source = "C2C", target = MappingConstants.THROW_EXCEPTION )
 ExternalOrderType orderTypeToExternalOrderType(OrderType orderType);
 
 Mapping result:
 IllegalArgumentException with the error message:
 Unexpected enum constant: C2C
    Author:
    Sjaak Derksen

    • Required Element Summary

      Required Elements 
      Modifier and Type Required Element Description
      String source
      The source value constant to use for this mapping.
      String target
      The target value constant to use for this mapping.