/**
* 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;
}
@Override
public synchronized IndexIterator iter(final IndexToken it) {
final byte[] tok = it.get();
// wildcard search
final FTLexer lexer = (FTLexer) it;
final FTOpt opt = lexer.ftOpt();
if (opt.is(WC)) return wc(tok);
// fuzzy search
if (opt.is(FZ)) return fuzzy(tok, lexer.lserror(tok));
// return cached or new result
final IndexEntry e = entry(tok);
return e.size > 0 ? iter(e.offset, e.size, inZ, tok) : FTIndexIterator.FTEMPTY;
}
/**
* 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;
}
/**
* Returns a scan-based index iterator.
*
* @param lex lexer, including the queried value
* @return node iterator
* @throws QueryException query exception
*/
private FTIndexIterator scan(final FTLexer lex) throws QueryException {
final FTLexer input = new FTLexer(ftt.opt);
final FTTokens fttokens = ftt.cache(lex.get());
return new FTIndexIterator() {
final int sz = data.meta.size;
int pre = -1, ps;
@Override
public int pre() {
return pre;
}
@Override
public boolean more() {
while (++pre < sz) {
if (data.kind(pre) != Data.TEXT) continue;
input.init(data.text(pre, true));
matches.reset(ps);
try {
if (ftt.contains(fttokens, input) != 0) return true;
} catch (final QueryException ignore) {
// ignore exceptions
}
}
return false;
}
@Override
public FTMatches matches() {
return matches;
}
@Override
public void pos(final int p) {
ps = p;
}
@Override
public int size() {
// worst case
return Math.max(1, sz >>> 1);
}
};
}
/**
* Builds full-text information.
*
* @param d data reference
* @param p pre value
* @param str string value
* @return number of added nodes
*/
TokenList build(final Data d, final int p, final byte[] str) {
final FTPos ftp = ftpos.get(d, p);
if (ftp == null) return null;
boolean marked = false;
final TokenList tl = new TokenList();
final TokenBuilder tb = new TokenBuilder();
final FTLexer lex = new FTLexer().sc().init(str);
int len = -ftlen;
while (lex.hasNext()) {
final FTSpan span = lex.next();
// check if current text is still to be marked or already marked
if (ftp.contains(span.pos) || marked) {
if (tb.size() != 0) {
// write current text node
tl.add(tb.finish());
len += tb.size();
tb.reset();
// skip construction
if (len >= 0 && tl.size() > 1 && !marked) break;
}
if (!marked) tl.add((byte[]) null);
marked ^= true;
}
// add span
tb.add(span.text);
}
// write last text node
if (tb.size() != 0) {
tl.add(tb.finish());
len += tb.size();
}
// chop first and last text
if (len > 0) {
final int ts = tl.size();
// get first text (empty if it is a full-text match)
final byte[] first = tl.get(0) != null ? tl.get(0) : EMPTY;
// get last text (empty if it is a full-text match)
final byte[] last = tl.get(ts - 2) != null ? tl.get(ts - 1) : EMPTY;
if (first != EMPTY) {
// remove leading characters of first text
final double l = first.length + last.length;
final int ll = Math.min(first.length, (int) (first.length / l * len));
tl.set(0, concat(DOTS, subtoken(first, ll)));
len -= ll;
}
if (last != EMPTY && len > 0) {
// remove trailing characters of last text
final int ll = Math.min(last.length, len);
tl.set(ts - 1, concat(subtoken(last, 0, last.length - ll), DOTS));
len -= ll;
}
// still too much text: shorten inner texts
for (int t = ts - 2; t > 0 && len > 0; t--) {
final byte[] txt = tl.get(t);
// skip elements, marked texts and too short text snippets
if (txt == null || tl.get(t - 1) == null) continue;
final int ll = Math.min(txt.length, len);
tl.set(
t,
concat(
subtoken(txt, 0, (txt.length - ll) / 2),
DOTS,
subtoken(txt, (txt.length + ll) / 2)));
len -= ll;
}
}
return tl;
}
