TermVectors are per-document and do not contain payloads. You are reading the per-document TermVectors which is a "small index" *stored* for each document as a binary blob. This blob only contains the terms of this document with its positions/offsets, but no payloads (offsets are used e.g. for highlighting).
To retrieve payloads, you have to use the main TermsEnum and main posting lists, but this does *not* work per document. In general you would execute a query and then retrieve the payload for each hit while iterating the scorer (e.g. function queries can do this). Uwe ----- Uwe Schindler H.-H.-Meier-Allee 63, D-28213 Bremen http://www.thetaphi.de eMail: u...@thetaphi.de > -----Original Message----- > From: Carsten Schnober [mailto:schno...@ids-mannheim.de] > Sent: Tuesday, April 23, 2013 1:04 PM > To: java-user > Subject: Reading Payloads > > Hi, > I'm trying to extract payloads from an index for specific tokens the following > way (inserting sample document number and term): > > Terms terms = reader.getTermVector(16504, "term"); TokenStream > tokenstream = TokenSources.getTokenStream(terms); > while (tokenstream.incrementToken()) { > OffsetAttribute offset = tokenstream.getAttribute(OffsetAttribute.class); > int start = offset.startOffset(); > int end = offset.endOffset(); > String token = > tokenstream.getAttribute(CharTermAttribute.class).toString(); > > PayloadAttribute payloadAttr = > tokenstream.addAttribute(PayloadAttribute.class); > BytesRef payloadBytes = payloadAttr.getPayload(); > > ... > } > > This works fine for the OffsetAttribute and the CharTermAttribute, but > payloadAttr.getPayload() always returns null for all documents and all > tokens, unfortunately. However, I know that the payloads are stored in the > index as I can retrieve them through a SpanQuery with Spans.getPayload(). I > actually expect every token to carry a payload, as I'm my custom tokenizer > implementation has the following lines: > > public class KoraTokenizer extends Tokenizer { > ... > private PayloadAttribute payloadAttr = > addAttribute(PayloadAttribute.class); > ... > public boolean incrementToken() { > ... > payloadAttr.setPayload(new BytesRef(payloadString)); > ... > } > ... > } > > I've asserted that the payloadString variable is never an empty String and as > I > said above, I can retrieve the Payloads with Spans.getPayload(). So what do I > do wrong in my > tokenstream.addAttribute(PayloadAttribute.class) call? BTW, I used > tokenstream.getAttribute() before as for the other attributes but this > obviously threw an IllegalArgumentException so I implemented the > recommendation given in the documentation and replaced it by > addAttribute(). > > Thanks! > Carsten > > > > > -- > Institut für Deutsche Sprache | http://www.ids-mannheim.de > Projekt KorAP | http://korap.ids-mannheim.de > Tel. +49-(0)621-43740789 | schno...@ids-mannheim.de > Korpusanalyseplattform der nächsten Generation Next Generation Corpus > Analysis Platform > > --------------------------------------------------------------------- > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > For additional commands, e-mail: java-user-h...@lucene.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
