svn commit: r1330915 - /lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java

[rm...@apache.org]

Author: rmuir
Date: Thu Apr 26 16:09:08 2012
New Revision: 1330915

URL: http://svn.apache.org/viewvc?rev=1330915&view=rev
Log:
LUCENE-2946: doc 4.0 stored fields format

Modified:
    lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java

Modified: lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java
URL: http://svn.apache.org/viewvc/lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java?rev=1330915&r1=1330914&r2=1330915&view=diff
==============================================================================
--- lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java (original)
+++ lucene/dev/trunk/lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40StoredFieldsFormat.java Thu Apr 26 16:09:08 2012
@@ -25,10 +25,58 @@ import org.apache.lucene.codecs.StoredFi
 import org.apache.lucene.codecs.StoredFieldsWriter;
 import org.apache.lucene.index.FieldInfos;
 import org.apache.lucene.index.SegmentInfo;
+import org.apache.lucene.store.DataOutput; // javadocs
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 
-/** @lucene.experimental */
+/** 
+ * Lucene 4.0 Stored Fields Format.
+ * <p>Stored fields are represented by two files:</p>
+ * <ol>
+ * <li><a name="field_index" id="field_index"></a>
+ * <p>The field index, or <tt>.fdx</tt> file.</p>
+ * <p>This is used to find the location within the field data file of the fields
+ * of a particular document. Because it contains fixed-length data, this file may
+ * be easily randomly accessed. The position of document <i>n</i> 's field data is
+ * the {@link DataOutput#writeLong Uint64} at <i>n*8</i> in this file.</p>
+ * <p>This contains, for each document, a pointer to its field data, as
+ * follows:</p>
+ * <ul>
+ * <li>FieldIndex (.fdx) --&gt; &lt;FieldValuesPosition&gt; <sup>SegSize</sup></li>
+ * <li>FieldValuesPosition --&gt; {@link DataOutput#writeLong Uint64}</li>
+ * </ul>
+ * </li>
+ * <li>
+ * <p><a name="field_data" id="field_data"></a>The field data, or <tt>.fdt</tt> file.</p>
+ * <p>This contains the stored fields of each document, as follows:</p>
+ * <ul>
+ * <li>FieldData (.fdt) --&gt; &lt;DocFieldData&gt; <sup>SegSize</sup></li>
+ * <li>DocFieldData --&gt; FieldCount, &lt;FieldNum, Bits, Value&gt;
+ * <sup>FieldCount</sup></li>
+ * <li>FieldCount --&gt; {@link DataOutput#writeVInt VInt}</li>
+ * <li>FieldNum --&gt; {@link DataOutput#writeVInt VInt}</li>
+ * <li>Bits --&gt; {@link DataOutput#writeByte Byte}</li>
+ * <ul>
+ * <li>low order bit reserved.</li>
+ * <li>second bit is one for fields containing binary data</li>
+ * <li>third bit reserved.</li>
+ * <li>4th to 6th bit (mask: 0x7&lt;&lt;3) define the type of a numeric field:
+ * <ul>
+ * <li>all bits in mask are cleared if no numeric field at all</li>
+ * <li>1&lt;&lt;3: Value is Int</li>
+ * <li>2&lt;&lt;3: Value is Long</li>
+ * <li>3&lt;&lt;3: Value is Int as Float (as of {@link Float#intBitsToFloat(int)}</li>
+ * <li>4&lt;&lt;3: Value is Long as Double (as of {@link Double#longBitsToDouble(long)}</li>
+ * </ul>
+ * </li>
+ * </ul>
+ * <li>Value --&gt; String | BinaryValue | Int | Long (depending on Bits)</li>
+ * <li>BinaryValue --&gt; ValueSize, &lt;{@link DataOutput#writeByte Byte}&gt;^ValueSize</li>
+ * <li>ValueSize --&gt; {@link DataOutput#writeVInt VInt}</li>
+ * </li>
+ * </ul>
+ * </ol>
+ * @lucene.experimental */
 public class Lucene40StoredFieldsFormat extends StoredFieldsFormat {
 
   @Override