package org.exist.xquery.modules.ngram.query;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.exist.dom.DocumentSet;
import org.exist.dom.ExtArrayNodeSet;
import org.exist.dom.NodeSet;
import org.exist.dom.QName;
import org.exist.indexing.ngram.NGramIndexWorker;
import org.exist.xquery.XPathException;
import org.exist.xquery.modules.ngram.NGramSearch;
public class AlternativeStrings implements EvaluatableExpression, MergeableExpression {
/**
*
*/
private final NGramSearch nGramSearch;
final Set<String> strings;
public AlternativeStrings(NGramSearch nGramSearch, final Set<String> strings) {
this.nGramSearch = nGramSearch;
this.strings = strings;
}
@Override
public NodeSet eval(
final NGramIndexWorker index, final DocumentSet docs, final List<QName> qnames, final NodeSet nodeSet,
final int axis, final int expressionId) throws XPathException {
NodeSet result = new ExtArrayNodeSet();
for (String s : strings) {
result.addAll(nGramSearch.fixedStringSearch(index, docs, qnames, s, nodeSet, axis));
}
result.iterate(); // ensure result is ready to use
return result;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder("AlternativeStrings(");
for (String str : strings) {
builder.append(", ");
builder.append(str);
}
builder.append(")");
return builder.toString();
}
@Override
public AlternativeStrings mergeWith(final WildcardedExpression otherExpression) {
Set<String> concatenatedStrings = null;
if (otherExpression instanceof FixedString) {
FixedString fixedString = (FixedString) otherExpression;
concatenatedStrings = new HashSet<String>(strings.size());
for (String s : strings)
concatenatedStrings.add(s + fixedString.fixedString);
} else {
AlternativeStrings otherAlternatives = (AlternativeStrings) otherExpression;
concatenatedStrings = new HashSet<String>(strings.size() * otherAlternatives.strings.size());
for (String s : strings)
for (String os : otherAlternatives.strings)
concatenatedStrings.add(s + os);
}
return new AlternativeStrings(this.nGramSearch, concatenatedStrings);
}
@Override
public boolean mergeableWith(final WildcardedExpression otherExpression) {
return ((otherExpression instanceof FixedString) || (otherExpression instanceof AlternativeStrings));
}
}