org.apache.lucene.index.PostingsEnum Maven / Gradle / Ivy
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/*
* 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.
*/
package org.apache.lucene.index;
import java.io.IOException;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.BytesRef;
/**
* Iterates through the postings. NOTE: you must first call {@link #nextDoc} before using any of the
* per-doc methods.
*/
public abstract class PostingsEnum extends DocIdSetIterator {
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you don't require per-document
* postings in the returned enum.
*/
public static final short NONE = 0;
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you require term frequencies
* in the returned enum.
*/
public static final short FREQS = 1 << 3;
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you require term positions in
* the returned enum.
*/
public static final short POSITIONS = FREQS | 1 << 4;
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you require offsets in the
* returned enum.
*/
public static final short OFFSETS = POSITIONS | 1 << 5;
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} if you require payloads in the
* returned enum.
*/
public static final short PAYLOADS = POSITIONS | 1 << 6;
/**
* Flag to pass to {@link TermsEnum#postings(PostingsEnum, int)} to get positions, payloads and
* offsets in the returned enum
*/
public static final short ALL = OFFSETS | PAYLOADS;
/** Returns true if the given feature is requested in the flags, false otherwise. */
public static boolean featureRequested(int flags, short feature) {
return (flags & feature) == feature;
}
/** Sole constructor. (For invocation by subclass constructors, typically implicit.) */
protected PostingsEnum() {}
/**
* Returns term frequency in the current document, or 1 if the field was indexed with {@link
* IndexOptions#DOCS}. Do not call this before {@link #nextDoc} is first called, nor after {@link
* #nextDoc} returns {@link DocIdSetIterator#NO_MORE_DOCS}.
*
* NOTE: if the {@link PostingsEnum} was obtain with {@link #NONE}, the result of this
* method is undefined.
*/
public abstract int freq() throws IOException;
/**
* Returns the next position, or -1 if positions were not indexed. Calling this more than {@link
* #freq()} times is undefined.
*/
public abstract int nextPosition() throws IOException;
/** Returns start offset for the current position, or -1 if offsets were not indexed. */
public abstract int startOffset() throws IOException;
/** Returns end offset for the current position, or -1 if offsets were not indexed. */
public abstract int endOffset() throws IOException;
/**
* Returns the payload at this position, or null if no payload was indexed. You should not modify
* anything (neither members of the returned BytesRef nor bytes in the byte[]).
*/
public abstract BytesRef getPayload() throws IOException;
}