@Override
        protected boolean shouldConvert(Expression exp) {
            if (!(exp instanceof SummaryExpression)) {
                return false;
            }
            String fieldName = ((SummaryExpression)exp).getFieldName();
            return fieldName == null || fieldName.equals(find);
        }
Adds a "fieldName_zcurve" long attribute and "fieldName.distance" and "FieldName.position" summary fields to all position type fields.

@author bratseth
config-model/src/main/java/com/yahoo/schema/processing/CreatePositionZCurve.java