package org.apache.lucene.codecs.lucene42;
/*
* 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.codecs.CodecUtil;
import org.apache.lucene.codecs.FieldInfosFormat;
import org.apache.lucene.codecs.FieldInfosReader;
import org.apache.lucene.codecs.FieldInfosWriter;
import org.apache.lucene.index.FieldInfo.DocValuesType; // javadoc
import org.apache.lucene.store.DataOutput; // javadoc
/**
* Lucene 4.2 Field Infos format.
* <p>
* <p>Field names are stored in the field info file, with suffix <tt>.fnm</tt>.</p>
* <p>FieldInfos (.fnm) --> Header,FieldsCount, <FieldName,FieldNumber,
* FieldBits,DocValuesBits,Attributes> <sup>FieldsCount</sup></p>
* <p>Data types:
* <ul>
* <li>Header --> {@link CodecUtil#checkHeader CodecHeader}</li>
* <li>FieldsCount --> {@link DataOutput#writeVInt VInt}</li>
* <li>FieldName --> {@link DataOutput#writeString String}</li>
* <li>FieldBits, DocValuesBits --> {@link DataOutput#writeByte Byte}</li>
* <li>FieldNumber --> {@link DataOutput#writeInt VInt}</li>
* <li>Attributes --> {@link DataOutput#writeStringStringMap Map<String,String>}</li>
* </ul>
* </p>
* Field Descriptions:
* <ul>
* <li>FieldsCount: the number of fields in this file.</li>
* <li>FieldName: name of the field as a UTF-8 String.</li>
* <li>FieldNumber: the field's number. Note that unlike previous versions of
* Lucene, the fields are not numbered implicitly by their order in the
* file, instead explicitly.</li>
* <li>FieldBits: a byte containing field options.
* <ul>
* <li>The low-order bit is one for indexed fields, and zero for non-indexed
* fields.</li>
* <li>The second lowest-order bit is one for fields that have term vectors
* stored, and zero for fields without term vectors.</li>
* <li>If the third lowest order-bit is set (0x4), offsets are stored into
* the postings list in addition to positions.</li>
* <li>Fourth bit is unused.</li>
* <li>If the fifth lowest-order bit is set (0x10), norms are omitted for the
* indexed field.</li>
* <li>If the sixth lowest-order bit is set (0x20), payloads are stored for the
* indexed field.</li>
* <li>If the seventh lowest-order bit is set (0x40), term frequencies and
* positions omitted for the indexed field.</li>
* <li>If the eighth lowest-order bit is set (0x80), positions are omitted for the
* indexed field.</li>
* </ul>
* </li>
* <li>DocValuesBits: a byte containing per-document value types. The type
* recorded as two four-bit integers, with the high-order bits representing
* <code>norms</code> options, and the low-order bits representing
* {@code DocValues} options. Each four-bit integer can be decoded as such:
* <ul>
* <li>0: no DocValues for this field.</li>
* <li>1: NumericDocValues. ({@link DocValuesType#NUMERIC})</li>
* <li>2: BinaryDocValues. ({@code DocValuesType#BINARY})</li>
* <li>3: SortedDocValues. ({@code DocValuesType#SORTED})</li>
* </ul>
* </li>
* <li>Attributes: a key-value map of codec-private attributes.</li>
* </ul>
*
* @lucene.experimental
* @deprecated Only for reading old 4.2-4.5 segments
*/
@Deprecated
public class Lucene42FieldInfosFormat extends FieldInfosFormat {
private final FieldInfosReader reader = new Lucene42FieldInfosReader();
/** Sole constructor. */
public Lucene42FieldInfosFormat() {
}
@Override
public FieldInfosReader getFieldInfosReader() throws IOException {
return reader;
}
@Override
public FieldInfosWriter getFieldInfosWriter() throws IOException {
throw new UnsupportedOperationException("this codec can only be used for reading");
}
/** Extension of field infos */
static final String EXTENSION = "fnm";
// Codec header
static final String CODEC_NAME = "Lucene42FieldInfos";
static final int FORMAT_START = 0;
static final int FORMAT_CURRENT = FORMAT_START;
// Field flags
static final byte IS_INDEXED = 0x1;
static final byte STORE_TERMVECTOR = 0x2;
static final byte STORE_OFFSETS_IN_POSTINGS = 0x4;
static final byte OMIT_NORMS = 0x10;
static final byte STORE_PAYLOADS = 0x20;
static final byte OMIT_TERM_FREQ_AND_POSITIONS = 0x40;
static final byte OMIT_POSITIONS = -128;
}