Following discussions on the dev list today, tweak the logic for sizing the HSSFCells array on a HSSFRow to reduce memory over allocation in many use cases (now cribbed from the size of the row, and uses the ArrayList growth metric)

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1095229 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 11 insertions, 3 deletions

diff --git a/src/documentation/content/xdocs/status.xml b/src/documentation/content/xdocs/status.xml
index 76d616f47f..5a90ab94e0 100644
--- a/src/documentation/content/xdocs/status.xml
+++ b/src/documentation/content/xdocs/status.xml
@@ -34,6 +34,7 @@
 
     <changes>
         <release version="3.8-beta3" date="2011-??-??">
+           <action dev="poi-developers" type="fix">Tweak the logic for sizing the HSSFCells array on a HSSFRow to reduce memory over allocation in many use cases</action>
            <action dev="poi-developers" type="add">49765 - Support for adding a picture to a XSSFRun</action>
            <action dev="poi-developers" type="fix">Rename/Move xssf.model.Table to xssf.usermodel.XSSFTable as it now has usermodel-like features</action>
            <action dev="poi-developers" type="fix">51061 - Correct target URI for new XSSF Tables</action>
diff --git a/src/java/org/apache/poi/hssf/usermodel/HSSFRow.java b/src/java/org/apache/poi/hssf/usermodel/HSSFRow.java
index 3d1c73497b..4d8102867f 100644
--- a/src/java/org/apache/poi/hssf/usermodel/HSSFRow.java
+++ b/src/java/org/apache/poi/hssf/usermodel/HSSFRow.java
@@ -41,7 +41,7 @@ public final class HSSFRow implements Row {
     public final static int INITIAL_CAPACITY = 5;
 
     private int rowNum;
-    private HSSFCell[] cells=new HSSFCell[INITIAL_CAPACITY];
+    private HSSFCell[] cells;
 
     /**
      * reference to low level representation
@@ -84,6 +84,12 @@ public final class HSSFRow implements Row {
         this.sheet = sheet;
         row = record;
         setRowNum(record.getRowNumber());
+        
+        // Size the initial cell list such that a read only case won't waste
+        //  lots of memory, and a create/read followed by adding new cells can
+        //  add a bit without needing a resize
+        cells = new HSSFCell[record.getLastCol()+INITIAL_CAPACITY];
+        
         // Don't trust colIx boundaries as read by other apps
         // set the RowRecord empty for the moment
         record.setEmpty();
@@ -300,9 +306,10 @@ public final class HSSFRow implements Row {
         // re-allocate cells array as required.
         if(column>=cells.length) {
             HSSFCell[] oldCells=cells;
-            int newSize=oldCells.length*2;
+            // New size based on the same logic as ArrayList
+            int newSize=oldCells.length*3/2+1;
             if(newSize<column+1) {
-                newSize=column+1;
+                newSize=column+INITIAL_CAPACITY;
             }
             cells=new HSSFCell[newSize];
             System.arraycopy(oldCells,0,cells,0,oldCells.length);