@Override
    public Long getVersionNo() {
        return asDocMeta().version();
    }

    public void setVersionNo(final Long version) {
        asDocMeta().version(version);
    }

    public void addField(final String key, final Object value) {
        fields.put(key, value);
    }

    public String getLogMessage() {
        return getUrl();
    }

    @Override
    public Map<String, Object> toSource() {