@Override
public TextPattern combineWithPrecedingPart(TextPattern previousPart) {
if (previousPart.hasConstantLength()) {
// We "gobble up" the previous part and adjust our left matching edge.
// This should make filtering more efficient, since we will likely have fewer hits to filter.
TextPatternPositionFilter result = (TextPatternPositionFilter) clone();
result.clauses.set(0, new TextPatternSequence(previousPart, clauses.get(0)));
result.adjustLeft(previousPart.getMinLength());
return result;
}
return super.combineWithPrecedingPart(previousPart);
}
@Override
public TextPattern rewrite() {
TextPattern producer = clauses.get(0).rewrite();
TextPattern filter = clauses.get(1).rewrite();
if (!invert
&& op != Operation.STARTS_AT
&& op != Operation.ENDS_AT
&& producer instanceof TextPatternAnyToken) {
// We're filtering "all n-grams of length min-max".
// Use the special optimized TextPatternFilterNGrams.
TextPatternAnyToken tp = (TextPatternAnyToken) producer;
return new TextPatternFilterNGrams(filter, op, tp.getMinLength(), tp.getMaxLength());
}
if (producer != clauses.get(0) || filter != clauses.get(1)) {
TextPatternPositionFilter result =
new TextPatternPositionFilter(producer, filter, op, invert);
result.leftAdjust = leftAdjust;
result.rightAdjust = rightAdjust;
return result;
}
return this;
}