package org.apache.lucene.index;
/*
* 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.FieldInfo.IndexOptions;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.Bits; // javadocs
/** Iterates through the documents and term freqs.
* NOTE: you must first call {@link #nextDoc} before using
* any of the per-doc methods. */
public abstract class DocsEnum extends DocIdSetIterator {
/**
* Flag to pass to {@link TermsEnum#docs(Bits,DocsEnum,int)} if you don't
* require term frequencies in the returned enum. When passed to
* {@link TermsEnum#docsAndPositions(Bits,DocsAndPositionsEnum,int)} means
* that no offsets and payloads will be returned.
*/
public static final int FLAG_NONE = 0x0;
/** Flag to pass to {@link TermsEnum#docs(Bits,DocsEnum,int)}
* if you require term frequencies in the returned enum. */
public static final int FLAG_FREQS = 0x1;
private AttributeSource atts = null;
/** Sole constructor. (For invocation by subclass
* constructors, typically implicit.) */
protected DocsEnum() {
}
/**
* Returns term frequency in the current document, or 1 if the field was
* indexed with {@link IndexOptions#DOCS_ONLY}. Do not call this before
* {@link #nextDoc} is first called, nor after {@link #nextDoc} returns
* {@link DocIdSetIterator#NO_MORE_DOCS}.
*
* <p>
* <b>NOTE:</b> if the {@link DocsEnum} was obtain with {@link #FLAG_NONE},
* the result of this method is undefined.
*/
public abstract int freq() throws IOException;
/** Returns the related attributes. */
public AttributeSource attributes() {
if (atts == null) atts = new AttributeSource();
return atts;
}
}