//                                                                            Accessor
    //                                                                            ========
    public String getBoostExpr() {
        checkSpecifiedProperty("boostExpr");
        return convertEmptyToNull(boostExpr);
    }

    public void setBoostExpr(String value) {
        registerModifiedProperty("boostExpr");

     * @param rule the boost document rule containing match and boost expressions
     */
    public DocBoostMatcher(final BoostDocumentRule rule) {
        matchExpression = rule.getUrlExpr();
        boostExpression = rule.getBoostExpr();
        scriptType = ComponentUtil.getFessConfig().getCrawlerDefaultScript();
    }

    /**
     * Determines if the given document data matches the configured match expression.
     *

    //                                       ---------------
    protected final Map<String, PropertyGateway> _epgMap = newHashMap();
    {
        setupEpg(_epgMap, et -> ((BoostDocumentRule) et).getBoostExpr(),
                (et, vl) -> ((BoostDocumentRule) et).setBoostExpr(DfTypeUtil.toString(vl)), "boostExpr");
        setupEpg(_epgMap, et -> ((BoostDocumentRule) et).getCreatedBy(),