{
final String id = value( el, EL_ID ).required();
final Set<String> contexts = SetFactory.unmodifiable( values( el, EL_CONTEXT ) );
final Set<String> overrides = SetFactory.unmodifiable( values( el, EL_OVERRIDES ) );
final Class<? extends Service> implementation = context.findClass( value( el, EL_IMPLEMENTATION ).required() );
final String conditionClassName = value( el, EL_CONDITION ).optional();
Class<? extends ServiceCondition> condition = null;
if( conditionClassName != null )