/**
* Generates a list of Highlighted query fragments for each item in a list of documents, or
* returns null if highlighting is disabled.
*
* @param docs query results
* @param query the query
* @param req the current request
* @param defaultFields default list of fields to summarize
* @return NamedList containing a NamedList for each document, which in turns contains sets
* (field, summary) pairs.
*/
@Override
@SuppressWarnings("unchecked")
public NamedList<Object> doHighlighting(
DocList docs, Query query, SolrQueryRequest req, String[] defaultFields) throws IOException {
SolrParams params = req.getParams();
if (!isHighlightingEnabled(params)) return null;
SolrIndexSearcher searcher = req.getSearcher();
IndexSchema schema = searcher.getSchema();
NamedList fragments = new SimpleOrderedMap();
String[] fieldNames = getHighlightFields(query, req, defaultFields);
Set<String> fset = new HashSet<String>();
{
// pre-fetch documents using the Searcher's doc cache
for (String f : fieldNames) {
fset.add(f);
}
// fetch unique key if one exists.
SchemaField keyField = schema.getUniqueKeyField();
if (null != keyField) fset.add(keyField.getName());
}
// get FastVectorHighlighter instance out of the processing loop
FastVectorHighlighter fvh =
new FastVectorHighlighter(
// FVH cannot process hl.usePhraseHighlighter parameter per-field basis
params.getBool(HighlightParams.USE_PHRASE_HIGHLIGHTER, true),
// FVH cannot process hl.requireFieldMatch parameter per-field basis
params.getBool(HighlightParams.FIELD_MATCH, false));
fvh.setPhraseLimit(params.getInt(HighlightParams.PHRASE_LIMIT, Integer.MAX_VALUE));
FieldQuery fieldQuery = fvh.getFieldQuery(query, searcher.getIndexReader());
// Highlight each document
DocIterator iterator = docs.iterator();
for (int i = 0; i < docs.size(); i++) {
int docId = iterator.nextDoc();
Document doc = searcher.doc(docId, fset);
NamedList docSummaries = new SimpleOrderedMap();
for (String fieldName : fieldNames) {
fieldName = fieldName.trim();
if (useFastVectorHighlighter(params, schema, fieldName))
doHighlightingByFastVectorHighlighter(
fvh, fieldQuery, req, docSummaries, docId, doc, fieldName);
else doHighlightingByHighlighter(query, req, docSummaries, docId, doc, fieldName);
}
String printId = schema.printableUniqueKey(doc);
fragments.add(printId == null ? null : printId, docSummaries);
}
return fragments;
}
private void doHighlightingByFastVectorHighlighter(
FastVectorHighlighter highlighter,
FieldQuery fieldQuery,
SolrQueryRequest req,
NamedList docSummaries,
int docId,
Document doc,
String fieldName)
throws IOException {
SolrParams params = req.getParams();
SolrFragmentsBuilder solrFb = getSolrFragmentsBuilder(fieldName, params);
String[] snippets =
highlighter.getBestFragments(
fieldQuery,
req.getSearcher().getIndexReader(),
docId,
fieldName,
params.getFieldInt(fieldName, HighlightParams.FRAGSIZE, 100),
params.getFieldInt(fieldName, HighlightParams.SNIPPETS, 1),
getFragListBuilder(fieldName, params),
getFragmentsBuilder(fieldName, params),
solrFb.getPreTags(params, fieldName),
solrFb.getPostTags(params, fieldName),
getEncoder(fieldName, params));
if (snippets != null && snippets.length > 0) docSummaries.add(fieldName, snippets);
else alternateField(docSummaries, params, doc, fieldName);
}