public void verify(String val, int index) {
            if (val != null && getTypeSpec() != null) {
                TypeSpec spec = getTypeSpec();
                spec.checkValue(getName(), val, index);
            }
        }
An array def is a ConfigDefinition with only one other type of scalar def.
@author vegardh
config/src/main/java/com/yahoo/vespa/config/ConfigDefinition.java