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December 16, 2010

Groovy Goodness: Transform String into Enum

After reading Groovy, State of the Union - Groovy Grails eXchange 2010 by Guillaume Laforge I discovered that in Groovy 1.7.6 we can transform a String into a Enum value. We can use type coersion or the as keyword to turn a String or GString into a corresponding Enum value (if possible).

enum Compass {

// Coersion with as keyword.
def north = 'NORTH' as Compass
assert north == Compass.NORTH

// Coersion by type.
Compass south = 'south'.toUpperCase()
assert south == Compass.SOUTH

def result = ['EA', 'WE'].collect {
    // Coersion of GString to Enum.
    "${it}ST" as Compass
assert result[0] == Compass.EAST
assert result[1] == Compass.WEST