private Map getExcerpt()

in oak-lucene/src/main/java/org/apache/jackrabbit/oak/plugins/index/lucene/LucenePropertyIndex.java [620:726]
89 lines of code
26 McCabe index (conditional complexity)

    private Map<String, String> getExcerpt(Query query, Set<String> excerptFields,
                              Analyzer analyzer, IndexSearcher searcher, ScoreDoc doc, FieldInfos fieldInfos)
            throws IOException {
        Set<String> excerptFieldNames = Sets.newHashSet();
        Map<String, String> fieldNameToColumnNameMap = Maps.newHashMap();
        Map<String, String> columnNameToExcerpts = Maps.newHashMap();
        Set<String> nodeExcerptColumns = Sets.newHashSet();

        excerptFields.forEach(columnName -> {
            String fieldName;
            if (REP_EXCERPT.equals(columnName)) {
                fieldName = FulltextIndexConstants.EXCERPT_NODE_FIELD_NAME;
            } else {
                fieldName = columnName.substring(REP_EXCERPT.length() + 1, columnName.length() - 1);
            }

            if (!FulltextIndexConstants.EXCERPT_NODE_FIELD_NAME.equals(fieldName)) {
                excerptFieldNames.add(fieldName);
                fieldNameToColumnNameMap.put(fieldName, columnName);
            } else {
                nodeExcerptColumns.add(columnName);
            }
        });

        final boolean requireNodeLevelExcerpt = nodeExcerptColumns.size() > 0;

        int docID = doc.doc;
        List<String> names = new LinkedList<>();

        for (IndexableField field : searcher.getIndexReader().document(docID).getFields()) {
            String name = field.name();
            // postings highlighter can be used on analyzed fields with docs, freqs, positions and offsets stored.
            if (name.startsWith(FieldNames.ANALYZED_FIELD_PREFIX) && fieldInfos.hasProx() && fieldInfos.hasOffsets()) {
                names.add(name);
            }
        }

        if (!requireNodeLevelExcerpt) {
            names.retainAll(excerptFieldNames);
        }

        if (names.size() > 0) {
            int[] maxPassages = new int[names.size()];
            Arrays.fill(maxPassages, 1);
            try {
                Map<String, String[]> stringMap = postingsHighlighter.highlightFields(names.toArray(new String[names.size()]),
                        query, searcher, new int[]{docID}, maxPassages);
                for (Map.Entry<String, String[]> entry : stringMap.entrySet()) {
                    String value = Arrays.toString(entry.getValue());
                    if (value.contains("<b>")) {
                        String fieldName = entry.getKey();
                        String columnName = fieldNameToColumnNameMap.get(fieldName);

                        columnNameToExcerpts.put(columnName, value);
                    }
                }
            } catch (Exception e) {
                LOG.debug("postings highlighting failed", e);
            }
        }

        // fallback if no excerpt could be retrieved using postings highlighter
        if (columnNameToExcerpts.size() == 0) {
            for (IndexableField field : searcher.getIndexReader().document(doc.doc).getFields()) {
                String name = field.name();
                // only full text or analyzed fields
                if (name.startsWith(FieldNames.FULLTEXT) || name.startsWith(FieldNames.ANALYZED_FIELD_PREFIX)) {
                    String text = field.stringValue();
                    TokenStream tokenStream = analyzer.tokenStream(name, text);

                    try {
                        TextFragment[] textFragments = highlighter.getBestTextFragments(tokenStream, text, true, 1);
                        if (textFragments != null && textFragments.length > 0) {
                            for (TextFragment fragment : textFragments) {
                                String columnName = null;
                                if (name.startsWith(FieldNames.ANALYZED_FIELD_PREFIX)) {
                                    columnName = fieldNameToColumnNameMap.get(name.substring(FieldNames.ANALYZED_FIELD_PREFIX.length()));
                                }
                                if (columnName == null && requireNodeLevelExcerpt) {
                                    columnName = name;
                                }

                                if (columnName != null) {
                                    columnNameToExcerpts.put(columnName, fragment.toString());
                                }
                            }
                            if (excerptFieldNames.size() == 0) {
                                break;
                            }
                        }
                    } catch (InvalidTokenOffsetsException e) {
                        LOG.error("highlighting failed", e);
                    }
                }
            }
        }

        if (requireNodeLevelExcerpt) {
            String nodeExcerpt = Joiner.on("...").join(columnNameToExcerpts.values());

            nodeExcerptColumns.forEach(nodeExcerptColumnName -> columnNameToExcerpts.put(nodeExcerptColumnName, nodeExcerpt));
        }

        columnNameToExcerpts.keySet().retainAll(excerptFields);

        return columnNameToExcerpts;
    }