Examples with CoveringQuery org.apache.lucene.search.CoveringQuery used on opensource projects

Example 1 with CoveringQuery

use of org.apache.lucene.search.CoveringQuery in project ranger by apache.

the class SubsetQueryPlugin method createParser.

@Override
public QParser createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {
    return new QParser(qstr, localParams, params, req) {

        @Override
        public Query parse() throws SyntaxError {
            String fieldName = Preconditions.checkNotNull(localParams.get(SETVAL_FIELD_NAME));
            String countFieldName = Preconditions.checkNotNull(localParams.get(COUNT_FIELD_NAME));
            boolean allowMissingValues = Boolean.parseBoolean(Preconditions.checkNotNull(localParams.get(MISSING_VAL_ALLOWED)));
            String wildcardToken = localParams.get(WILDCARD_CHAR);
            LongValuesSource minimumNumberMatch = LongValuesSource.fromIntField(countFieldName);
            Collection<Query> queries = new ArrayList<>();
            String fieldVals = Preconditions.checkNotNull(localParams.get(SETVAL_PARAM_NAME));
            for (String v : fieldVals.split(",")) {
                queries.add(new TermQuery(new Term(fieldName, v)));
            }
            if (wildcardToken != null && !wildcardToken.equals("")) {
                queries.add(new TermQuery(new Term(fieldName, wildcardToken)));
            }
            if (allowMissingValues) {
                // To construct this query we need to do a little trick tho construct a test for an empty field as follows:
                // (*:* AND -fieldName:*) ==> parses as: (+*:* -fieldName:*)
                // It is a feature of Lucene that pure negative queries are not allowed (although Solr allows them as a top level construct)
                // therefore we need to AND with *:*
                // We can then pass this BooleanQuery to the CoveringQuery as one of its allowed matches.
                BooleanQuery.Builder builder = new BooleanQuery.Builder();
                builder.add(new BooleanClause(new MatchAllDocsQuery(), BooleanClause.Occur.SHOULD));
                builder.add(new BooleanClause(new WildcardQuery(new Term(fieldName, "*")), BooleanClause.Occur.MUST_NOT));
                queries.add(builder.build());
            }
            return new CoveringQuery(queries, minimumNumberMatch);
        }
    };
}