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

Example 1 with Similarity

use of org.apache.lucene.search.Similarity in project neo4j-mobile-android by neo4j-contrib.

the class IndexType method getIndexType.

static IndexType getIndexType(IndexIdentifier identifier, Map<String, String> config) {
    String type = config.get(LuceneIndexImplementation.KEY_TYPE);
    IndexType result = null;
    Similarity similarity = getCustomSimilarity(config);
    boolean toLowerCase = parseBoolean(config.get(LuceneIndexImplementation.KEY_TO_LOWER_CASE), true);
    Analyzer customAnalyzer = getCustomAnalyzer(config);
    if (type != null) {
        // Use the built in alternatives... "exact" or "fulltext"
        if (type.equals("exact")) {
            result = EXACT;
        } else if (type.equals("fulltext")) {
            Analyzer analyzer = customAnalyzer;
            if (analyzer == null) {
                analyzer = toLowerCase ? LuceneDataSource.LOWER_CASE_WHITESPACE_ANALYZER : LuceneDataSource.WHITESPACE_ANALYZER;
            }
            result = new CustomType(analyzer, toLowerCase, similarity);
        }
    } else {
        // Use custom analyzer
        if (customAnalyzer == null) {
            throw new IllegalArgumentException("No 'type' was given (which can point out " + "built-in analyzers, such as 'exact' and 'fulltext')" + " and no 'analyzer' was given either (which can point out a custom " + Analyzer.class.getName() + " to use)");
        }
        result = new CustomType(customAnalyzer, toLowerCase, similarity);
    }
    return result;
}

Example 2 with Similarity

use of org.apache.lucene.search.Similarity in project graphdb by neo4j-attic.

the class LuceneDataSource method getIndexWriter.

synchronized IndexWriter getIndexWriter(IndexIdentifier identifier) {
    Triplet<IndexWriter, AtomicBoolean, SnapshotDeletionPolicy> writer = indexWriters.get(identifier);
    if (writer != null) {
        return writer.first();
    }
    try {
        Directory dir = getDirectory(baseStorePath, identifier);
        directoryExists(dir);
        IndexType type = getType(identifier);
        SnapshotDeletionPolicy deletionPolicy = new MultipleBackupDeletionPolicy();
        IndexWriter indexWriter = new IndexWriter(dir, type.analyzer, deletionPolicy, MaxFieldLength.UNLIMITED);
        writer = Triplet.of(indexWriter, new AtomicBoolean(), deletionPolicy);
        Similarity similarity = type.getSimilarity();
        if (similarity != null) {
            writer.first().setSimilarity(similarity);
        }
        // TODO We should tamper with this value and see how it affects the
        // general performance. Lucene docs says rather <10 for mixed
        // reads/writes
        // writer.setMergeFactor( 8 );
        indexWriters.put(identifier, writer);
        return writer.first();
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

Example 3 with Similarity

use of org.apache.lucene.search.Similarity in project graphdb by neo4j-attic.

the class IndexType method getIndexType.

static IndexType getIndexType(IndexIdentifier identifier, Map<String, String> config) {
    String type = config.get(LuceneIndexImplementation.KEY_TYPE);
    IndexType result = null;
    Similarity similarity = getCustomSimilarity(config);
    boolean toLowerCase = parseBoolean(config.get(LuceneIndexImplementation.KEY_TO_LOWER_CASE), true);
    Analyzer customAnalyzer = getCustomAnalyzer(config);
    if (type != null) {
        // Use the built in alternatives... "exact" or "fulltext"
        if (type.equals("exact")) {
            result = EXACT;
        } else if (type.equals("fulltext")) {
            Analyzer analyzer = customAnalyzer;
            if (analyzer == null) {
                analyzer = toLowerCase ? LuceneDataSource.LOWER_CASE_WHITESPACE_ANALYZER : LuceneDataSource.WHITESPACE_ANALYZER;
            }
            result = new CustomType(analyzer, toLowerCase, similarity);
        }
    } else {
        // Use custom analyzer
        if (customAnalyzer == null) {
            throw new IllegalArgumentException("No 'type' was given (which can point out " + "built-in analyzers, such as 'exact' and 'fulltext')" + " and no 'analyzer' was given either (which can point out a custom " + Analyzer.class.getName() + " to use)");
        }
        result = new CustomType(customAnalyzer, toLowerCase, similarity);
    }
    return result;
}

Example 4 with Similarity

use of org.apache.lucene.search.Similarity in project greplin-lucene-utils by Cue.

the class PredicateQuery method createWeight.

/**
 * Returns a Weight that applies the predicate to the enclosed query's Weight.
 * This is accomplished by overriding the Scorer returned by the Weight.
 * @param searcher the searcher to create a weight for.
 * @return a Weight that applies the predicate to the query.
 * @throws IOException if IO issues occur.
 */
@Override
public Weight createWeight(final Searcher searcher) throws IOException {
    final Weight weight = this.query.createWeight(searcher);
    final Similarity similarity = this.query.getSimilarity(searcher);
    return new Weight() {

        private float value;

        // pass these methods through to enclosed query's weight
        @Override
        public float getValue() {
            return this.value;
        }

        @Override
        public boolean scoresDocsOutOfOrder() {
            return false;
        }

        public float sumOfSquaredWeights() throws IOException {
            return weight.sumOfSquaredWeights() * getBoost() * getBoost();
        }

        @Override
        public void normalize(final float v) {
            // incorporate boost
            weight.normalize(v * getBoost());
            this.value = weight.getValue();
        }

        @Override
        public Explanation explain(final IndexReader reader, final int i) throws IOException {
            Explanation inner = weight.explain(reader, i);
            Bits predicate = PredicateQuery.this.predicate.get(reader);
            if (predicate.get(i)) {
                return inner;
            } else {
                Explanation result = new Explanation(0.0f, "failure to match predicate: " + predicate.toString());
                result.addDetail(inner);
                return result;
            }
        }

        @Override
        public Query getQuery() {
            return PredicateQuery.this;
        }

        @Override
        public Scorer scorer(final IndexReader reader, final boolean scoreDocsInOrder, final boolean topScorer) throws IOException {
            Bits predicate = PredicateQuery.this.predicate.get(reader);
            return PredicateQuery.getScorer(reader, similarity, weight, this, predicate);
        }
    };
}

Example 5 with Similarity

use of org.apache.lucene.search.Similarity in project greplin-lucene-utils by Cue.

the class ConstantQueryNormBoostingQuery method rewrite.

@Override
public Query rewrite(final IndexReader reader) throws IOException {
    BooleanQuery result = new BooleanQuery() {

        @Override
        public Similarity getSimilarity(final Searcher searcher) {
            final Similarity base = searcher.getSimilarity();
            return new DefaultSimilarity() {

                @Override
                public float queryNorm(final float sumOfSquaredWeights) {
                    return base.queryNorm(sumOfSquaredWeights);
                }

                @Override
                public float coord(final int overlap, final int max) {
                    switch(overlap) {
                        case // matched only one clause
                        1:
                            return 1.0f;
                        case // matched both clauses
                        2:
                            return ConstantQueryNormBoostingQuery.this.boost;
                        default:
                            return 0.0f;
                    }
                }
            };
        }
    };
    result.add(this.match, BooleanClause.Occur.MUST);
    result.add(this.context, BooleanClause.Occur.SHOULD);
    return result;
}