Classes which implement this interface may participate in the data binding process as formatted value converters.
import org.grails.databinding.converters.FormattedValueConverter
class FormattedStringValueConverter implements FormattedValueConverter {
    def convert(value, String format) {
        if('UPPERCASE' == format) {
            value = value.toUpperCase()
        } else if('LOWERCASE' == format) {
            value = value.toLowerCase()
        }
        value
    }
    Class getTargetType() {
        // specifies the type to which this converter may be applied
        String
    }
}
 | Type Params | Return Type | Name and description | 
|---|---|---|
|  | java.lang.Object | convert(java.lang.Object value, java.lang.String format)Return a formatted value | 
|  | java.lang.Class<?> | getTargetType()@return the output type of this converter | 
Return a formatted value
value -  The value to be formattedformat -  The format String