package org.apache.lucene.search;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.IOException;
import org.apache.lucene.index.*;
/**
* Position of a term in a document that takes into account the term offset within the phrase.
*/
final class PhrasePositions {
int doc; // current doc
int position; // position in doc
int count; // remaining pos in this doc
int offset; // position in phrase
final DocsAndPositionsEnum postings; // stream of docs & positions
PhrasePositions next; // used to make lists
boolean repeats; // there's other pp for same term (e.g. query="1st word 2nd word"~1)
PhrasePositions(DocsAndPositionsEnum postings, int o) {
this.postings = postings;
offset = o;
}
final boolean next() throws IOException { // increments to next doc
doc = postings.nextDoc();
if (doc == postings.NO_MORE_DOCS) {
return false;
}
return true;
}
final boolean skipTo(int target) throws IOException {
doc = postings.advance(target);
if (doc == postings.NO_MORE_DOCS) {
return false;
}
return true;
}
final void firstPosition() throws IOException {
count = postings.freq(); // read first pos
nextPosition();
}
/**
* Go to next location of this term current document, and set
* <code>position</code> as <code>location - offset</code>, so that a
* matching exact phrase is easily identified when all PhrasePositions
* have exactly the same <code>position</code>.
*/
final boolean nextPosition() throws IOException {
if (count-- > 0) { // read subsequent pos's
position = postings.nextPosition() - offset;
return true;
} else
return false;
}
}