Expand JavaDocs for DbiFlags as per native mdb_dbi_open docs

bp-alex · bp-alex · commit ae5e2bf03404 · 2017-07-18T16:42:29.000+10:00
diff --git a/src/main/java/org/lmdbjava/DbiFlags.java b/src/main/java/org/lmdbjava/DbiFlags.java
@@ -27,10 +27,20 @@ public enum DbiFlags implements MaskedFlag {
 
   /**
    * Use reverse string keys.
+   *
+   * <p>
+   * Keys are strings to be compared in reverse order, from the end of the
+   * strings to the beginning. By default, keys are treated as strings and
+   * compared from beginning to end.
    */
   MDB_REVERSEKEY(0x02),
   /**
    * Use sorted duplicates.
+   *
+   * <p>
+   * Duplicate keys may be used in the database. Or, from another perspective,
+   * keys may have multiple data items, stored in sorted order. By default keys
+   * must be unique and may have only a single data item.
    */
   MDB_DUPSORT(0x04),
   /**
@@ -40,18 +50,38 @@ public enum DbiFlags implements MaskedFlag {
   MDB_INTEGERKEY(0x08),
   /**
    * With {@link #MDB_DUPSORT}, sorted dup items have fixed size.
+   *
+   * <p>
+   * This flag may only be used in combination with {@link #MDB_DUPSORT}. This
+   * option tells the library that the data items for this database are all the
+   * same size, which allows further optimizations in storage and retrieval.
+   * When all data items are the same size, the {@link SeekOp#MDB_GET_MULTIPLE}
+   * and {@link SeekOp#MDB_NEXT_MULTIPLE} cursor operations may be used to
+   * retrieve multiple items at once.
    */
   MDB_DUPFIXED(0x10),
   /**
    * With {@link #MDB_DUPSORT}, dups are {@link #MDB_INTEGERKEY}-style integers.
+   *
+   * <p>
+   * This option specifies that duplicate data items are binary integers,
+   * similar to {@link #MDB_INTEGERKEY} keys.
    */
   MDB_INTEGERDUP(0x20),
   /**
    * With {@link #MDB_DUPSORT}, use reverse string dups.
+   *
+   * <p>
+   * This option specifies that duplicate data items should be compared as
+   * strings in reverse order.
    */
   MDB_REVERSEDUP(0x40),
   /**
-   * Create DB if not already existing.
+   * Create the named database if it doesn't exist.
+   *
+   * <p>
+   * This option is not allowed in a read-only transaction or a read-only
+   * environment.
    */
   MDB_CREATE(0x4_0000);
 
