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LUCENE-2946: doc 4.0 fieldinfos format 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1331781 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Robert Muir 2012-04-28 15:03:21 +00:00
parent 937658dbcf
commit 347019a36b
1 changed files with 66 additions and 0 deletions
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66
lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40FieldInfosFormat.java
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@ -23,9 +23,75 @@ import java.util.Set;
import org.apache.lucene.codecs.FieldInfosFormat;
import org.apache.lucene.codecs.FieldInfosReader;
import org.apache.lucene.codecs.FieldInfosWriter;
import org.apache.lucene.index.DocValues; // javadoc
import org.apache.lucene.index.DocValues.Type; // javadoc
import org.apache.lucene.index.SegmentInfo;
import org.apache.lucene.store.DataOutput; // javadoc
/**
* Lucene 4.0 Field Infos format.
* <p>
* <p>Field names are stored in the field info file, with suffix <tt>.fnm</tt>.</p>
* <p>FieldInfos (.fnm) --&gt; FNMVersion,FieldsCount, &lt;FieldName,FieldNumber,
* FieldBits,DocValuesBits&gt; <sup>FieldsCount</sup></p>
* <p>Data types:
* <ul>
* <li>FNMVersion, FieldsCount --&gt; {@link DataOutput#writeVInt VInt}</li>
* <li>FieldName --&gt; {@link DataOutput#writeString String}</li>
* <li>FieldBits, DocValuesBits --&gt; {@link DataOutput#writeByte Byte}</li>
* <li>FieldNumber --&gt; {@link DataOutput#writeInt Uint32}</li>
* </ul>
* </p>
* Field Descriptions:
* <ul>
* <li>FNMVersion is <code>Lucene40FieldInfosWriter.FORMAT_CURRENT</code>.</li>
* <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
* {@link DocValues} options. Each four-bit integer can be decoded as such:
* <ul>
* <li>0: no DocValues for this field.</li>
* <li>1: variable-width signed integers. ({@link Type#VAR_INTS VAR_INTS})</li>
* <li>2: 32-bit floating point values. ({@link Type#FLOAT_32 FLOAT_32})</li>
* <li>3: 64-bit floating point values. ({@link Type#FLOAT_64 FLOAT_64})</li>
* <li>4: fixed-length byte array values. ({@link Type#BYTES_FIXED_STRAIGHT BYTES_FIXED_STRAIGHT})</li>
* <li>5: fixed-length dereferenced byte array values. ({@link Type#BYTES_FIXED_DEREF BYTES_FIXED_DEREF})</li>
* <li>6: variable-length byte array values. ({@link Type#BYTES_VAR_STRAIGHT BYTES_VAR_STRAIGHT})</li>
* <li>7: variable-length dereferenced byte array values. ({@link Type#BYTES_VAR_DEREF BYTES_VAR_DEREF})</li>
* <li>8: 16-bit signed integers. ({@link Type#FIXED_INTS_16 FIXED_INTS_16})</li>
* <li>9: 32-bit signed integers. ({@link Type#FIXED_INTS_32 FIXED_INTS_32})</li>
* <li>10: 64-bit signed integers. ({@link Type#FIXED_INTS_64 FIXED_INTS_64})</li>
* <li>11: 8-bit signed integers. ({@link Type#FIXED_INTS_8 FIXED_INTS_8})</li>
* <li>12: fixed-length sorted byte array values. ({@link Type#BYTES_FIXED_SORTED BYTES_FIXED_SORTED})</li>
* <li>13: variable-length sorted byte array values. ({@link Type#BYTES_VAR_SORTED BYTES_VAR_SORTED})</li>
* </ul>
* </li>
* </ul>
*
* @lucene.experimental
*/
public class Lucene40FieldInfosFormat extends FieldInfosFormat {