From 2ec433e990672fc63e8bf251db018f3e1afe62a2 Mon Sep 17 00:00:00 2001
From: Michael Stack <stack@apache.org>
Date: Thu, 26 Feb 2009 18:21:49 +0000
Subject: [PATCH] HBASE-1188 Memory size of Java Objects - Make cacheable
 objects implement HeapSize

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@748259 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  2 ++
 .../org/apache/hadoop/hbase/io/HeapSize.java  | 36 +++++++++++++++++--
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 36870458345..543248629a6 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -63,6 +63,8 @@ Release 0.20.0 - Unreleased
                options show up (Erik Holstad via Stack)
    HBASE-1189  Changing the map type used internally for HbaseMapWritable
                (Erik Holstad via Stack)
+   HBASE-1188  Memory size of Java Objects - Make cacheable objects implement
+               HeapSize (Erik Holstad via Stack)
 
 Release 0.19.0 - 01/21/2009
   INCOMPATIBLE CHANGES
diff --git a/src/java/org/apache/hadoop/hbase/io/HeapSize.java b/src/java/org/apache/hadoop/hbase/io/HeapSize.java
index 3beea9df6a2..cfabf406d58 100644
--- a/src/java/org/apache/hadoop/hbase/io/HeapSize.java
+++ b/src/java/org/apache/hadoop/hbase/io/HeapSize.java
@@ -25,9 +25,41 @@ package org.apache.hadoop.hbase.io;
  * probably do not account for 32 vs 64 bit nor for different VM implemenations.
  */
 public interface HeapSize {
+  
+  /** Reference size is 8 bytes on 64-bit, 4 bytes on 32-bit */
+  static final int REFERENCE = 8;
+  
+  /** Object overhead is minimum 2 * reference size (8 bytes on 64-bit) */
+  static final int OBJECT = 2 * REFERENCE;
+  
+  /**
+   * The following types are always allocated in blocks of 8 bytes (on 64bit)
+   * For example, if you have two ints in a class, it will use 8 bytes.
+   * If you have three ints in a class, it will use 16 bytes.
+   */
+  static final int SHORT = 4;
+  static final int INT = 4;
+  static final int FLOAT = 4;
+  static final int BOOLEAN = 4;
+  static final int CHAR = 4;
+  static final int BYTE = 1;
+  
+  /** These types are always 8 bytes */
+  static final int DOUBLE = 8;
+  static final int LONG = 8;
+  
+  /** Array overhead */
+  static final int BYTE_ARRAY = REFERENCE;
+  static final int ARRAY = 3 * REFERENCE;
+  static final int MULTI_ARRAY = (4 * REFERENCE) + ARRAY;
+  
+  static final int BLOCK_SIZE_TAX = 8;
+
+  
+  
   /**
    * @return Approximate 'exclusive deep size' of implementing object.  Includes
    * count of payload and hosting object sizings.
-   */
+  */
   public long heapSize();
-}
\ No newline at end of file
+}