package org.apache.lucene.codecs;
/*
* 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.DocsAndPositionsEnum;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.MergeState;
import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.FixedBitSet;
/**
* Abstract API that consumes postings for an individual term.
* <p>
* The lifecycle is:
* <ol>
* <li>PostingsConsumer is returned for each term by
* {@link TermsConsumer#startTerm(BytesRef)}.
* <li>{@link #startDoc(int, int)} is called for each
* document where the term occurs, specifying id
* and term frequency for that document.
* <li>If positions are enabled for the field, then
* {@link #addPosition(int, BytesRef, int, int)}
* will be called for each occurrence in the
* document.
* <li>{@link #finishDoc()} is called when the producer
* is done adding positions to the document.
* </ol>
*
* @lucene.experimental
*/
public abstract class PostingsConsumer {
/** Sole constructor. (For invocation by subclass
* constructors, typically implicit.) */
protected PostingsConsumer() {
}
/** Adds a new doc in this term.
* <code>freq</code> will be -1 when term frequencies are omitted
* for the field. */
public abstract void startDoc(int docID, int freq) throws IOException;
/** Add a new position & payload, and start/end offset. A
* null payload means no payload; a non-null payload with
* zero length also means no payload. Caller may reuse
* the {@link BytesRef} for the payload between calls
* (method must fully consume the payload). <code>startOffset</code>
* and <code>endOffset</code> will be -1 when offsets are not indexed. */
public abstract void addPosition(int position, BytesRef payload, int startOffset, int endOffset) throws IOException;
/** Called when we are done adding positions & payloads
* for each doc. */
public abstract void finishDoc() throws IOException;
/** Default merge impl: append documents, mapping around
* deletes */
public TermStats merge(final MergeState mergeState, final DocsEnum postings, final FixedBitSet visitedDocs) throws IOException {
int df = 0;
long totTF = 0;
IndexOptions indexOptions = mergeState.fieldInfo.getIndexOptions();
if (indexOptions == IndexOptions.DOCS_ONLY) {
while(true) {
final int doc = postings.nextDoc();
if (doc == DocIdSetIterator.NO_MORE_DOCS) {
break;
}
visitedDocs.set(doc);
this.startDoc(doc, -1);
this.finishDoc();
df++;
}
totTF = -1;
} else if (indexOptions == IndexOptions.DOCS_AND_FREQS) {
while(true) {
final int doc = postings.nextDoc();
if (doc == DocIdSetIterator.NO_MORE_DOCS) {
break;
}
visitedDocs.set(doc);
final int freq = postings.freq();
this.startDoc(doc, freq);
this.finishDoc();
df++;
totTF += freq;
}
} else if (indexOptions == IndexOptions.DOCS_AND_FREQS_AND_POSITIONS) {
final DocsAndPositionsEnum postingsEnum = (DocsAndPositionsEnum) postings;
while(true) {
final int doc = postingsEnum.nextDoc();
if (doc == DocIdSetIterator.NO_MORE_DOCS) {
break;
}
visitedDocs.set(doc);
final int freq = postingsEnum.freq();
this.startDoc(doc, freq);
totTF += freq;
for(int i=0;i<freq;i++) {
final int position = postingsEnum.nextPosition();
final BytesRef payload = postingsEnum.getPayload();
this.addPosition(position, payload, -1, -1);
}
this.finishDoc();
df++;
}
} else {
assert indexOptions == IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS;
final DocsAndPositionsEnum postingsEnum = (DocsAndPositionsEnum) postings;
while(true) {
final int doc = postingsEnum.nextDoc();
if (doc == DocIdSetIterator.NO_MORE_DOCS) {
break;
}
visitedDocs.set(doc);
final int freq = postingsEnum.freq();
this.startDoc(doc, freq);
totTF += freq;
for(int i=0;i<freq;i++) {
final int position = postingsEnum.nextPosition();
final BytesRef payload = postingsEnum.getPayload();
this.addPosition(position, payload, postingsEnum.startOffset(), postingsEnum.endOffset());
}
this.finishDoc();
df++;
}
}
return new TermStats(df, indexOptions == IndexOptions.DOCS_ONLY ? -1 : totTF);
}
}