Entry Mapping

Not all enums classes that one wants to map have identical entries, or are not even both an enum class. If this is the case, Mappie cannot determine which source must map to which target.

Suppose Color has an extra entry Color.ORANGE, whilst Colour does not have Colour.ORANGE, but does have Colour.OTHER. In other words

enum class Color { RED, GREEN, BLUE, ORANGE; }

enum class Colour { RED, GREEN, BLUE, OTHER; }

We can generate a complete mapper by mapping Colour.ORANGE to Colour.OTHER via fromEnumEntry

object ColorMapper : EnumMappie<Color, Colour>() {
    override fun map(from: Color): Colour = mapping {
        Colour.OTHER fromEnumEntry Color.ORANGE
    }
}

Throwing an Exception #

We can also make the generated mapper throw an exception, similar to setting the global enum strictness property to true, but in a fine-grained manner. This can be done by mapping via thrownByEnumEntry.

For example the following snippet will generate a mapper in which the map function will throw an IllegalStateException when called with argument Color.ORANGE.

object ColorMapper : EnumMappie<Color, Colour>() {
    override fun map(from: Color): Colour = mapping {
        IllegalStateException() thrownByEnumEntry Color.ORANGE
    }
}