throw tooManyAttributes();
        }
        super.setRefid(ref);
    }

    public String getId() {
        if (isReference()) {
            return getRef().getId();
        }
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUrl() {
        if (isReference()) {
            return getRef().getUrl();
        }
        return url;
    }

    public void setUrl(String url) {
        checkAttributesAllowed();
        this.url = url;
    }

    public String getType() {
        if (isReference()) {
            return getRef().getType();
        }
        return (type != null) ? type : "default";
    }

    public void setType(String type) {
        checkAttributesAllowed();
        this.type = type;
    }

    public String getMirrorOf() {