Example usage for org.apache.solr.util DOMUtil getAttr

Introduction

In this page you can find the example usage for org.apache.solr.util DOMUtil getAttr.

Prototype

public static String getAttr(Node node, String name, String missing_err) 

Source Link

Usage

From source file:com.billiger.solr.handler.component.QLTBComponent.java

License:Apache License

/**
 * Load the QLTB map from a Config.//  w  w w.ja  v a  2s  .c om
 *
 * Read and process the "boosts/query" XPath nodes from the given
 * Config, and build them into a QLTB map. The XML format is described
 * in the class documentation.
 *
 * The result of this function is a map of (analyzed) query strings
 * with their respective lists of boosted query terms. These are
 * ConstantScoreQuery instances for each term with the corresponding
 * boost factor. (Invalid - i.e. non-numerical - boost factors are
 * logged as warnings).
 *
 * The SOLR core that is passed into this function is necessary for
 * determinating the FieldType of the boosted fields. Only with the
 * correct field type is it possible to boost non-string fields, as
 * these non-string values need to be ft.readableToIndexed().
 *
 * @param cfg
 *            Config object to read the XML QLTB from
 * @param core
 *            SOLR Core the query is performed on
 * @return QLTB map
 *
 * @throws IOException
 *             If the query could not be analysed
 */
private Map<String, List<Query>> loadQLTBMap(final Config cfg, final SolrCore core) throws IOException {
    Map<String, List<Query>> map = new HashMap<String, List<Query>>();
    NodeList nodes = (NodeList) cfg.evaluate("boosts/query", XPathConstants.NODESET);
    for (int i = 0; i < nodes.getLength(); i++) {
        Node node = nodes.item(i);
        String qstr = DOMUtil.getAttr(node, "text", "missing query 'text'");
        qstr = getAnalyzedQuery(qstr);
        NodeList children = node.getChildNodes();
        List<Query> termBoosts = new ArrayList<Query>();
        for (int j = 0; j < children.getLength(); j++) {
            Node child = children.item(j);
            if (!child.getNodeName().equals("term")) {
                continue;
            }
            String field = DOMUtil.getAttr(child, "field", "missing 'field'");
            String value = DOMUtil.getAttr(child, "value", "missing 'value'");
            String boost = DOMUtil.getAttr(child, "boost", "missing 'boost'");
            float termBoost = 1;
            try {
                termBoost = Float.parseFloat(boost);
            } catch (NumberFormatException e) {
                log.warn("invalid boost " + boost + " for query \"" + qstr + "\", term: \"" + field + ":"
                        + value + "\": " + e.getMessage());
                continue;
            }
            // without readableToIndexed QLTB boosting would only work
            // for string field types
            FieldType ft = core.getLatestSchema().getField(field).getType();
            value = ft.readableToIndexed(value);
            Term t = new Term(field, value);
            TermQuery tq = new TermQuery(t);
            ConstantScoreQuery csq = new ConstantScoreQuery(tq);
            csq.setBoost(termBoost);
            termBoosts.add(csq);
        }
        map.put(qstr, termBoosts);
    }
    return map;
}

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