SXSSF documentation and polishing

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1133372 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 52 insertions, 10 deletions

diff --git a/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFSheet.java b/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
index be90606e1b..baea693418 100644
--- a/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
+++ b/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFSheet.java
@@ -17,15 +17,10 @@
 
 package org.apache.poi.xssf.streaming;
 
+import java.io.*;
 import java.util.Iterator;
 import java.util.TreeMap;
 import java.util.Map;
-import java.io.Writer;
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.FileInputStream;
 
 import org.apache.poi.ss.usermodel.*;
 import org.apache.poi.ss.util.CellReference;
@@ -46,7 +41,7 @@ public class SXSSFSheet implements Sheet, Cloneable
     XSSFSheet _sh;
     TreeMap<Integer,SXSSFRow> _rows=new TreeMap<Integer,SXSSFRow>();
     SheetDataWriter _writer;
-    int _randomAccessWindowSize=5000;
+    int _randomAccessWindowSize = SXSSFWorkbook.DEFAULT_WINDOW_SIZE;
 
     public SXSSFSheet(SXSSFWorkbook workbook,XSSFSheet xSheet) throws IOException
     {
@@ -1243,7 +1238,7 @@ public class SXSSFSheet implements Sheet, Cloneable
         {
             _fd = File.createTempFile("sheet", ".xml");
             _fd.deleteOnExit();
-            _out = new FileWriter(_fd);
+            _out = new BufferedWriter(new FileWriter(_fd));
             _out.write("<sheetData>\n");
         }
         public int getNumberOfFlushedRows()
@@ -1262,9 +1257,10 @@ public class SXSSFSheet implements Sheet, Cloneable
         {
             _fd.delete();
         }
-        public InputStream getWorksheetXMLInputStream() throws IOException 
+        public InputStream getWorksheetXMLInputStream() throws IOException
         {
             _out.write("</sheetData>");
+            _out.flush();
             _out.close();
             return new FileInputStream(_fd);
         }
@@ -1275,7 +1271,7 @@ public class SXSSFSheet implements Sheet, Cloneable
          * @param rownum 0-based row number
          * @param row a row
          */
-        public void writeRow(int rownum,SXSSFRow row) throws IOException 
+        public void writeRow(int rownum,SXSSFRow row) throws IOException
         {
             if(_numberOfFlushedRows==0)
                 _lowestIndexOfFlushedRows=rownum;
diff --git a/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFWorkbook.java b/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFWorkbook.java
index aa17b536a0..365e58b337 100644
--- a/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFWorkbook.java
+++ b/src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFWorkbook.java
@@ -50,11 +50,56 @@ import org.apache.poi.ss.usermodel.Row.MissingCellPolicy;
 */
 public class SXSSFWorkbook implements Workbook
 {
+    /**
+     * Specifies how many rows can be accessed at most via getRow().
+     * When a new node is created via createRow() and the total number
+     * of unflushed records would exeed the specified value, then the
+     * row with the lowest index value is flushed and cannot be accessed
+     * via getRow() anymore.
+     */
+    public static final int DEFAULT_WINDOW_SIZE = 100;
+
     XSSFWorkbook _wb=new XSSFWorkbook();
 
     HashMap<SXSSFSheet,XSSFSheet> _sxFromXHash=new HashMap<SXSSFSheet,XSSFSheet>();
     HashMap<XSSFSheet,SXSSFSheet> _xFromSxHash=new HashMap<XSSFSheet,SXSSFSheet>();
 
+    int _randomAccessWindowSize = DEFAULT_WINDOW_SIZE;
+
+    /**
+     * Construct a new workbook
+     */
+    public SXSSFWorkbook(){
+
+    }
+
+    /**
+     * Construct an empty workbook and specify the window for row access.
+     * <p>
+     * When a new node is created via createRow() and the total number
+     * of unflushed records would exeed the specified value, then the
+     * row with the lowest index value is flushed and cannot be accessed
+     * via getRow() anymore.
+     * </p>
+     * <p>
+     * A value of -1 indicates unlimited access. In this case all
+     * records that have not been flushed by a call to flush() are available
+     * for random access.
+     * <p>
+     * <p></p>
+     * A value of 0 is not allowed because it would flush any newly created row
+     * without having a chance to specify any cells.
+     * </p>
+     *
+     * @param rowAccessWindowSize
+     */
+    public SXSSFWorkbook(int rowAccessWindowSize){
+        if(rowAccessWindowSize == 0 || rowAccessWindowSize < -1) {
+            throw new IllegalArgumentException("rowAccessWindowSize must be greater than 0 or -1");
+        }
+        _randomAccessWindowSize = rowAccessWindowSize;
+    }
+
     XSSFSheet getXSSFSheet(SXSSFSheet sheet)
     {
         XSSFSheet result=_sxFromXHash.get(sheet);
@@ -303,6 +348,7 @@ public class SXSSFWorkbook implements Workbook
         {
             throw new RuntimeException(ioe);
         }
+        sxSheet.setRandomAccessWindowSize(_randomAccessWindowSize);
         registerSheetMapping(sxSheet,xSheet);
         return sxSheet;
     }