svn commit: r513130 - /xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java

Author: vgritsenko
Date: Wed Feb 28 20:09:11 2007
New Revision: 513130

URL: http://svn.apache.org/viewvc?view=rev&rev=513130
Log:
javadoc

Modified:
    xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java

Modified: xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java
URL: http://svn.apache.org/viewvc/xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java?view=diff&rev=513130&r1=513129&r2=513130
==============================================================================
--- xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java (original)
+++ xml/xindice/trunk/java/src/org/apache/xindice/core/filer/BTree.java Wed Feb 28 20:09:11 2007
@@ -42,8 +42,8 @@
 /**
  * BTree represents a Variable Magnitude Simple-Prefix B+Tree File.
  * A BTree is a bit flexible in that it can be used for set or
- * map-based indexing.  HashFiler uses the BTree as a set for
- * producing RecordSet entries.  The Indexers use BTree as a map for
+ * map-based indexing. {@link BTreeFiler} uses the BTree as a set for
+ * producing RecordSet entries. The Indexers use BTree as a map for
  * indexing entity and attribute values in Documents.
  *
  * <br>
@@ -73,15 +73,21 @@
 
     private static final Log log = LogFactory.getLog(BTree.class);
 
-    protected static final byte LEAF = 1;
+    protected static final byte LEAF   = 1;
     protected static final byte BRANCH = 2;
     protected static final byte STREAM = 3;
 
     /**
-     * Cache of the recently used tree nodes.
+     * Identity map of the recently used tree nodes to ensure that same
+     * node is present in the memory once and only once.
      *
-     * Cache contains weak references to the BTreeNode objects, keys are page numbers (Long objects).
-     * Access synchronized by this map itself.
+     * <p>Cache contains weak references to the BTreeNode objects, keys
+     * are page numbers (Long objects). Access synchronized by this map
+     * object itself.
+     *
+     * <p>This identity map can be made into cache to store nodes for
+     * extended time periods, but that might not be necessary since
+     * documents are cached on the Collection level.
      */
     private final Map cache = new WeakHashMap();