Java 类org.apache.lucene.search.postingshighlight.PostingsHighlighter 实例源码

@Override
public NamedList<Object> doHighlighting(DocList docs, Query query, SolrQueryRequest req, String[] defaultFields) throws IOException {
  final SolrParams params = req.getParams(); 

  // if highlighting isnt enabled, then why call doHighlighting?
  if (!isHighlightingEnabled(params))
    return null;

  SolrIndexSearcher searcher = req.getSearcher();
  int[] docIDs = toDocIDs(docs);

  // fetch the unique keys
  String[] keys = getUniqueKeys(searcher, docIDs);

  // query-time parameters
  String[] fieldNames = getHighlightFields(query, req, defaultFields);

  int maxPassages[] = new int[fieldNames.length];
  for (int i = 0; i < fieldNames.length; i++) {
    maxPassages[i] = params.getFieldInt(fieldNames[i], HighlightParams.SNIPPETS, 1);
  }

  PostingsHighlighter highlighter = getHighlighter(req);
  Map<String,String[]> snippets = highlighter.highlightFields(fieldNames, query, searcher, docIDs, maxPassages);
  return encodeSnippets(keys, fieldNames, snippets);
}

@Override
public NamedList<Object> doHighlighting(DocList docs, Query query, SolrQueryRequest req, String[] defaultFields) throws IOException {
  final SolrParams params = req.getParams(); 

  // if highlighting isnt enabled, then why call doHighlighting?
  if (!isHighlightingEnabled(params))
    return null;

  SolrIndexSearcher searcher = req.getSearcher();
  int[] docIDs = toDocIDs(docs);

  // fetch the unique keys
  String[] keys = getUniqueKeys(searcher, docIDs);

  // query-time parameters
  String[] fieldNames = getHighlightFields(query, req, defaultFields);

  int maxPassages[] = new int[fieldNames.length];
  for (int i = 0; i < fieldNames.length; i++) {
    maxPassages[i] = params.getFieldInt(fieldNames[i], HighlightParams.SNIPPETS, 1);
  }

  PostingsHighlighter highlighter = getHighlighter(req);
  Map<String,String[]> snippets = highlighter.highlightFields(fieldNames, query, searcher, docIDs, maxPassages);
  return encodeSnippets(keys, fieldNames, snippets);
}

@Test
public void testHighlightChapter5() throws IOException {
  // searching for "gas" didn't work on the Safari site

  InputStream ch5stream = getClass().getResourceAsStream("ch5.txt");
  String ch5 = IOUtils.toString(ch5stream);

  // add a single document to the index
  // configure field with offsets at index time
  FieldType offsetsType = new FieldType(TextField.TYPE_STORED);
  offsetsType.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS);
  Field text = new Field("text", ch5, offsetsType);

  Document doc = new Document();
  doc.add(new StringField("id", "ch5", Store.YES));
  doc.add(text);
  iw.addDocument(doc);
  iw.commit();

  DirectoryReader reader = DirectoryReader.open(iw, true);
  IndexSearcher searcher = new IndexSearcher(reader);

  // retrieve highlights at query time 
  PostingsHighlighter highlighter = new PostingsHighlighter(100000);
  Query query = new TermQuery(new Term("text", "gas"));
  TopDocs topDocs = searcher.search(query, 1);
  String highlights[] = highlighter.highlight("text", query, searcher, topDocs);
  assertEquals (1, highlights.length);
  assertNotNull ("PH returns null highlight", highlights[0]);
  assertTrue (highlights[0] + " \n does not contain <b>gas</b>", highlights[0].contains("<b>gas</b>"));
}

@Override
public void init(PluginInfo info) {
  Map<String,String> attributes = info.attributes;
  BreakIterator breakIterator = BreakIterator.getSentenceInstance(Locale.ROOT);
  PassageScorer scorer = new PassageScorer();

  // formatter parameters: preTag/postTag/ellipsis
  String preTag = attributes.get("preTag");
  if (preTag == null) {
    preTag = "<em>";
  }
  String postTag = attributes.get("postTag");
  if (postTag == null) {
    postTag = "</em>";
  }
  String ellipsis = attributes.get("ellipsis");
  if (ellipsis == null) {
    ellipsis = "... ";
  }
  PassageFormatter formatter = new PassageFormatter(preTag, postTag, ellipsis);

  // maximum content size to process
  int maxLength = PostingsHighlighter.DEFAULT_MAX_LENGTH;
  if (attributes.containsKey("maxLength")) {
    maxLength = Integer.parseInt(attributes.get("maxLength"));
  }
  highlighter = new PostingsHighlighter(maxLength, breakIterator, scorer, formatter);
}

@Override
public void init(PluginInfo info) {
  Map<String,String> attributes = info.attributes;
  BreakIterator breakIterator = BreakIterator.getSentenceInstance(Locale.ROOT);
  PassageScorer scorer = new PassageScorer();

  // formatter parameters: preTag/postTag/ellipsis
  String preTag = attributes.get("preTag");
  if (preTag == null) {
    preTag = "<em>";
  }
  String postTag = attributes.get("postTag");
  if (postTag == null) {
    postTag = "</em>";
  }
  String ellipsis = attributes.get("ellipsis");
  if (ellipsis == null) {
    ellipsis = "... ";
  }
  PassageFormatter formatter = new PassageFormatter(preTag, postTag, ellipsis);

  // maximum content size to process
  int maxLength = PostingsHighlighter.DEFAULT_MAX_LENGTH;
  if (attributes.containsKey("maxLength")) {
    maxLength = Integer.parseInt(attributes.get("maxLength"));
  }
  highlighter = new PostingsHighlighter(maxLength, breakIterator, scorer, formatter);
}

public LindenSnippetGenerator() {
  highlighter = new PostingsHighlighter();
}

/** Creates an instance of the Lucene PostingsHighlighter. Provided for subclass extension so that
 * a subclass can return a subclass of {@link PostingsSolrHighlighter.SolrExtendedPostingsHighlighter}. */
protected PostingsHighlighter getHighlighter(SolrQueryRequest req) {
  return new SolrExtendedPostingsHighlighter(req);
}

public SolrExtendedPostingsHighlighter(SolrQueryRequest req) {
  super(req.getParams().getInt(HighlightParams.MAX_CHARS, PostingsHighlighter.DEFAULT_MAX_LENGTH));
  this.params = req.getParams();
  this.schema = req.getSchema();
}

/** Creates an instance of the Lucene PostingsHighlighter. Provided for subclass extension so that
 * a subclass can return a subclass of {@link PostingsSolrHighlighter.SolrExtendedPostingsHighlighter}. */
@Override
protected PostingsHighlighter getHighlighter(SolrQueryRequest req) {
  return new SafariPostingsHighlighter(req);
}

/** Creates an instance of the Lucene PostingsHighlighter. Provided for subclass extension so that
 * a subclass can return a subclass of {@link PostingsSolrHighlighter.SolrExtendedPostingsHighlighter}. */
protected PostingsHighlighter getHighlighter(SolrQueryRequest req) {
  return new SolrExtendedPostingsHighlighter(req);
}

public SolrExtendedPostingsHighlighter(SolrQueryRequest req) {
  super(req.getParams().getInt(HighlightParams.MAX_CHARS, PostingsHighlighter.DEFAULT_MAX_LENGTH));
  this.params = req.getParams();
  this.schema = req.getSchema();
}