Custom Grails Property Editor

Grails uses Spring's mechanism for binding the html (String) representation of an object with the object representation on the server side. I wanted all my currency fields (which are BigDecimal) to be formatted with dollar signs so I declared a CustomPropertyEditorRegistrar to modify how the BigDecimal conversion.

1. Added this to my resources.groovy

configurer(org.springframework.beans.factory.config.CustomEditorConfigurer) {
propertyEditorRegistrars = [ref("registrar")]
}

registrar(com.sungard.stallion.format.CustomPropertyEditorRegistrar)

2. Create a class that implements PropertyEditorRegistrar

import org.springframework.beans.PropertyEditorRegistrar;
import org.springframework.beans.PropertyEditorRegistry;

public class CustomPropertyEditorRegistrar implements PropertyEditorRegistrar {
 public void registerCustomEditors(PropertyEditorRegistry registry) {
     registry.registerCustomEditor(java.math.BigDecimal.class, new CurrencyPropertyEditor());
 }
}

3. It seems like this could have been done in a single step... but also define the class that the Registrar adds which implements PropertyEditor. Spring provides a helper class, PropertyEditorSupport, that the custom editor can extend:

import java.math.BigDecimal;
import java.beans.PropertyEditor;
import java.beans.PropertyEditorSupport;

public class CurrencyPropertyEditor extends PropertyEditorSupport implements PropertyEditor {
  
   public void setAsText(String text) {
       setValue(... parsing goes here...);
   }
  
   public String getAsText() {
       Object value = getValue();
       if (value instanceof BigDecimal) {
           return ... formatting goes here...;
       }
       return ("" + value);
   }

}

- Ben Hidalgo