* The value is, e.g. boost <br>
     * comment: Field name for boost value in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexFieldBoost();

    /**
     * Get the value for the key 'index.field.created'. <br>
     * The value is, e.g. created <br>
     * comment: Field name for creation date in the index.