/**
* Extracts and indexes words from the specified data reference.
*
* @throws IOException I/O Exception
*/
final void index() throws IOException {
// delete old index
abort();
final Performance perf = Prop.debug ? new Performance() : null;
Util.debug(det());
for (pre = 0; pre < size; ++pre) {
if ((pre & 0xFFFF) == 0) check();
final int k = data.kind(pre);
if (k != Data.TEXT) {
if (scm == 1 && k == Data.DOC) unit.add(pre);
continue;
}
if (scm == 2) unit.add(pre);
pos = -1;
final StopWords sw = lex.ftOpt().sw;
lex.init(data.text(pre, true));
while (lex.hasNext()) {
final byte[] tok = lex.nextToken();
++pos;
// skip too long and stopword tokens
if (tok.length <= data.meta.maxlen && (sw.size() == 0 || !sw.contains(tok))) {
// check if main memory is exhausted
if ((ntok++ & 0xFFF) == 0 && scm == 0 && memFull()) {
// currently no frequency support for tf/idf based scoring
writeIndex(csize++);
Performance.gc(2);
}
index(tok);
}
}
}
// calculate term frequencies
if (scm > 0) {
maxfreq = new int[unit.size() + 1];
ntoken = new int[nrTokens()];
token = 0;
calcFreq();
}
// write tokens
token = 0;
write();
// set meta data
if (scm > 0) {
data.meta.maxscore = max;
data.meta.minscore = min;
}
data.meta.ftxtindex = true;
Util.memory(perf);
}
@Override
public boolean indexAccessible(final IndexInfo ii) {
/* If the following conditions yield true, the index is accessed:
* - all query terms are statically available
* - no FTTimes option is specified
* - explicitly set case, diacritics and stemming match options do not
* conflict with index options. */
data = ii.ic.data;
final MetaData md = data.meta;
final FTOpt fto = ftt.opt;
/* Index will be applied if no explicit match options have been set
* that conflict with the index options. As a consequence, though, index-
* based querying might yield other results than sequential scanning. */
if (occ != null
|| fto.cs != null && md.casesens == (fto.cs == FTCase.INSENSITIVE)
|| fto.isSet(DC) && md.diacritics != fto.is(DC)
|| fto.isSet(ST) && md.stemming != fto.is(ST)
|| fto.ln != null && !fto.ln.equals(md.language)) return false;
// adopt database options to tokenizer
fto.copy(md);
// estimate costs if text is not known at compile time
if (tokens == null) {
ii.costs = Math.max(2, data.meta.size / 30);
return true;
}
// summarize number of hits; break loop if no hits are expected
final FTLexer ft = new FTLexer(fto);
ii.costs = 0;
for (byte[] t : tokens) {
ft.init(t);
while (ft.hasNext()) {
final byte[] tok = ft.nextToken();
if (fto.sw != null && fto.sw.contains(tok)) continue;
if (fto.is(WC)) {
// don't use index if one of the terms starts with a wildcard
t = ft.get();
if (t[0] == '.') return false;
// don't use index if certain characters or more than 1 dot are found
int d = 0;
for (final byte w : t) {
if (w == '{' || w == '\\' || w == '.' && ++d > 1) return false;
}
}
// favor full-text index requests over exact queries
final int costs = data.costs(ft);
if (costs != 0) ii.costs += Math.max(2, costs / 100);
}
}
return true;
}
/**
* Caches and returns all unique tokens specified in a query.
*
* @param list token list
* @return token set
*/
private TokenSet unique(final TokenList list) {
// cache all query tokens in a set (duplicates are removed)
final TokenSet ts = new TokenSet();
switch (mode) {
case ALL:
case ANY:
for (final byte[] t : list) ts.add(t);
break;
case ALL_WORDS:
case ANY_WORD:
final FTLexer l = new FTLexer(ftt.opt);
for (final byte[] t : list) {
l.init(t);
while (l.hasNext()) ts.add(l.nextToken());
}
break;
case PHRASE:
final TokenBuilder tb = new TokenBuilder();
for (final byte[] t : list) tb.add(t).add(' ');
ts.add(tb.trim().finish());
}
return ts;
}