Katta docId to Document

How to use FieldCache in Katta, FieldCache expects IndexReader as arguments, then how to get IndexReader from Katta API. And In katta开发者_JAVA百科 the search method in LuceneClient.java returns Hits. From this I can get List, from that I can able to get each hit's docId, but I need particular field value of the docId in Katta. Please give me some coding example.

I've never worked with Katta, I worked with Solr and if I had to get document by its id and I had to use only Lucene classes, I'd use org.apache.lucene.search.IndexSearcher:

// when you figure out how to get IndexReader using Katta API, you'll be able to get the searcher
IndexSearcher searcher = new IndexSearcher(indexReader);
org.apache.lucene.document.Document doc = searcher.doc(docId);
String yourFieldValue = doc.get("yourFieldName");

you can't use the FieldCache on client side, since the IndexReader is located on the server side! But you can get field-values through the getDetails() method on LuceneClient.

final Hits hits = client.search(query, new String[] { INDEX_NAME }, 10);
for (final Hit hit : hits.getHits()) {
  final MapWritable details = client.getDetails(hit, new String[] { "path" });
  details.get(new Text("path"));

HTH Johannes