[github-184] New EmittingSXSSFWorkbook. Thanks to mobreza. This closes #184

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1879302 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/xssf/streaming/EmittingSXSSFSheet.java

@@ -0,0 +1,69 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.xssf.streaming;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import org.apache.poi.util.Beta;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+
+/**
+ * A variant of SXSSFSheet that uses IRowGenerator to create rows.
+ *
+ *  This variant is experimental and APIs may change at short notice.
+ *
+ * @see EmittingSXSSFWorkbook
+ * @since 5.0.0
+ */
+@Beta
+public class EmittingSXSSFSheet extends SXSSFSheet {
+    private IRowGenerator rowGenerator;
+    
+    public EmittingSXSSFSheet(EmittingSXSSFWorkbook workbook, XSSFSheet xSheet) throws IOException {
+        super(workbook, xSheet, workbook.getRandomAccessWindowSize());
+    }
+    
+    @Override
+    public InputStream getWorksheetXMLInputStream() throws IOException {
+        throw new RuntimeException("Not supported by EmittingSXSSFSheet");
+    }
+    
+    public void setRowGenerator(IRowGenerator rowGenerator) {
+        this.rowGenerator = rowGenerator;
+    }
+    
+    public void writeRows(OutputStream out) throws IOException {
+        // delayed creation of SheetDataWriter
+        _writer = ((EmittingSXSSFWorkbook) _workbook).createSheetDataWriter(out);
+        try {
+            if (this.rowGenerator != null) {
+                this.rowGenerator.generateRows(this);
+            }
+        } catch (Exception e) {
+            throw new IOException("Error generating Excel rows", e);
+        } finally {
+            // flush buffered rows
+            flushRows(0);
+            // flush writer buffer
+            _writer.close();
+            out.flush();
+        }
+    }
+}

src/ooxml/java/org/apache/poi/xssf/streaming/EmittingSXSSFWorkbook.java

@@ -0,0 +1,219 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.xssf.streaming;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.util.Beta;
+import org.apache.poi.util.POILogFactory;
+import org.apache.poi.util.POILogger;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+
+/**
+ * An variant of SXSSFWorkbook that avoids generating a temporary file and writes data directly to
+ * the provided OutputStream.
+ * 
+ * This variant is experimental and APIs may change at short notice.
+ * 
+ * @since 5.0.0
+ */
+@Beta
+public class EmittingSXSSFWorkbook extends SXSSFWorkbook {
+    private static final POILogger logger = POILogFactory.getLogger(EmittingSXSSFWorkbook.class);
+    
+    public EmittingSXSSFWorkbook() {
+        this(null);
+    }
+    
+    public EmittingSXSSFWorkbook(XSSFWorkbook workbook) {
+        this(workbook, SXSSFWorkbook.DEFAULT_WINDOW_SIZE);
+    }
+    
+    public EmittingSXSSFWorkbook(XSSFWorkbook workbook, int rowAccessWindowSize) {
+        super(workbook, rowAccessWindowSize, false, false);
+    }
+    
+    @Override
+    protected SheetDataWriter createSheetDataWriter() throws IOException {
+        throw new RuntimeException("Not supported by EmittingSXSSFWorkbook");
+    }
+    
+    protected StreamingSheetWriter createSheetDataWriter(OutputStream out) throws IOException {
+        return new StreamingSheetWriter(out);
+    }
+    
+    @Override
+    protected ISheetInjector createSheetInjector(SXSSFSheet sxSheet) throws IOException {
+        EmittingSXSSFSheet ssxSheet = (EmittingSXSSFSheet) sxSheet;
+        return (output) -> {
+            ssxSheet.writeRows(output);
+        };
+    }
+    
+    @Override
+    SXSSFSheet createAndRegisterSXSSFSheet(XSSFSheet xSheet) {
+        final EmittingSXSSFSheet sxSheet;
+        try {
+            sxSheet = new EmittingSXSSFSheet(this, xSheet);
+        } catch (IOException ioe) {
+            throw new RuntimeException(ioe);
+        }
+        registerSheetMapping(sxSheet, xSheet);
+        return sxSheet;
+    }
+    
+    public EmittingSXSSFSheet createSheet() {
+        return (EmittingSXSSFSheet) super.createSheet();
+    }
+    
+    public EmittingSXSSFSheet createSheet(String sheetname) {
+        return (EmittingSXSSFSheet) super.createSheet(sheetname);
+    }
+    
+    /**
+     * Returns an iterator of the sheets in the workbook in sheet order. Includes hidden and very hidden sheets.
+     *
+     * @return an iterator of the sheets.
+     */
+    @Override
+    public Iterator<Sheet> sheetIterator() {
+        return new SheetIterator<Sheet>();
+    }
+    
+    private final class SheetIterator<T extends Sheet> implements Iterator<T> {
+        final private Iterator<XSSFSheet> it;
+        
+        @SuppressWarnings("unchecked")
+        public SheetIterator() {
+            it = (Iterator<XSSFSheet>) (Iterator<? extends Sheet>) _wb.iterator();
+        }
+        
+        @Override
+        public boolean hasNext() {
+            return it.hasNext();
+        }
+        
+        @Override
+        @SuppressWarnings("unchecked")
+        public T next() throws NoSuchElementException {
+            final XSSFSheet xssfSheet = it.next();
+            EmittingSXSSFSheet sxSheet = (EmittingSXSSFSheet) getSXSSFSheet(xssfSheet);
+            return (T) (sxSheet == null ? xssfSheet : sxSheet);
+        }
+        
+        /**
+         * Unexpected behavior may occur if sheets are reordered after iterator has been created. Support for the remove
+         * method may be added in the future if someone can figure out a reliable implementation.
+         */
+        @Override
+        public void remove() throws IllegalStateException {
+            throw new UnsupportedOperationException("remove method not supported on XSSFWorkbook.iterator(). "
+                    + "Use Sheet.removeSheetAt(int) instead.");
+        }
+    }
+    
+    /**
+     * Alias for {@link #sheetIterator()} to allow foreach loops
+     */
+    @Override
+    public Iterator<Sheet> iterator() {
+        return sheetIterator();
+    }
+    
+    @Override
+    public SXSSFSheet getSheetAt(int index) {
+        throw new RuntimeException("Not supported by EmittingSXSSFWorkbook");
+    }
+    
+    public XSSFSheet getXSSFSheetAt(int index) {
+        return _wb.getSheetAt(index);
+    }
+    
+    /**
+     * Gets the sheet at the given index for streaming.
+     *
+     * @param index the index
+     * @return the streaming sheet at
+     */
+    public EmittingSXSSFSheet getStreamingSheetAt(int index) {
+        XSSFSheet xSheet = _wb.getSheetAt(index);
+        SXSSFSheet sxSheet = getSXSSFSheet(xSheet);
+        if (sxSheet == null && xSheet != null) {
+            return (EmittingSXSSFSheet) createAndRegisterSXSSFSheet(xSheet);
+        } else {
+            return (EmittingSXSSFSheet) sxSheet;
+        }
+    }
+    
+    @Override
+    public SXSSFSheet getSheet(String name) {
+        throw new RuntimeException("Not supported by EmittingSXSSFWorkbook");
+    }
+    
+    public XSSFSheet getXSSFSheet(String name) {
+        return _wb.getSheet(name);
+    }
+    
+    /**
+     * Gets sheet with the given name for streaming.
+     *
+     * @param name the name
+     * @return the streaming sheet
+     */
+    public EmittingSXSSFSheet getStreamingSheet(String name) {
+        XSSFSheet xSheet = _wb.getSheet(name);
+        EmittingSXSSFSheet sxSheet = (EmittingSXSSFSheet) getSXSSFSheet(xSheet);
+        if (sxSheet == null && xSheet != null) {
+            return (EmittingSXSSFSheet) createAndRegisterSXSSFSheet(xSheet);
+        } else {
+            return sxSheet;
+        }
+    }
+    
+    /**
+     * Removes sheet at the given index
+     *
+     * @param index of the sheet to remove (0-based)
+     */
+    @Override
+    public void removeSheetAt(int index) {
+        // Get the sheet to be removed
+        XSSFSheet xSheet = _wb.getSheetAt(index);
+        SXSSFSheet sxSheet = getSXSSFSheet(xSheet);
+        
+        // De-register it
+        _wb.removeSheetAt(index);
+        
+        // The sheet may not be a streaming sheet and is not mapped
+        if (sxSheet != null) {
+            deregisterSheetMapping(xSheet);
+            
+            // Clean up temporary resources
+            try {
+                sxSheet.dispose();
+            } catch (IOException e) {
+                logger.log(POILogger.WARN, e);
+            }
+        }
+    }
+}

src/ooxml/java/org/apache/poi/xssf/streaming/IRowGenerator.java

@@ -0,0 +1,37 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.xssf.streaming;
+
+import org.apache.poi.util.Beta;
+
+/**
+ * IRowGenerator for Emitting SXSSF sheets
+ *
+ * @see EmittingSXSSFWorkbook
+ */
+@Beta
+public interface IRowGenerator {
+    
+    /**
+     * Generate and add rows to the sheet
+     *
+     * @param sheet the sheet
+     * @throws Exception the exception
+     */
+    void generateRows(SXSSFSheet sheet) throws Exception;
+}

src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFFormulaEvaluator.java

@@ -106,12 +106,14 @@ public final class SXSSFFormulaEvaluator extends BaseXSSFFormulaEvaluator {
         // Process the sheets as best we can
         for (Sheet sheet : wb) {
             
+            if (sheet instanceof SXSSFSheet) {
                 // Check if any rows have already been flushed out
                 int lastFlushedRowNum = ((SXSSFSheet) sheet).getLastFlushedRowNum();
                 if (lastFlushedRowNum > -1) {
                     if (! skipOutOfWindow) throw new RowFlushedException(0);
                     logger.log(POILogger.INFO, "Rows up to " + lastFlushedRowNum + " have already been flushed, skipping");
                 }
+            }
             
             // Evaluate what we have
             for (Row r : sheet) {

src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFPicture.java

@@ -24,6 +24,7 @@ import org.apache.poi.openxml4j.opc.PackagePart;
 import org.apache.poi.ss.usermodel.Picture;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Shape;
+import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.ss.util.ImageUtils;
 import org.apache.poi.util.Internal;
@@ -201,7 +202,8 @@ public final class SXSSFPicture implements Picture {
         // THE FOLLOWING THREE LINES ARE THE MAIN CHANGE compared to the non-streaming version: use the SXSSF sheet,
 		// not the XSSF sheet (which never contais rows when using SXSSF)
         XSSFSheet xssfSheet = getSheet();
-        SXSSFSheet sheet = _wb.getSXSSFSheet(xssfSheet);
+        SXSSFSheet sxSheet = _wb.getSXSSFSheet(xssfSheet);
+        Sheet sheet = sxSheet == null ? xssfSheet : sxSheet;
         Row row = sheet.getRow(rowIndex);
         float height = row != null ?  row.getHeightInPoints() : sheet.getDefaultRowHeightInPoints();
         return height * Units.PIXEL_DPI / Units.POINT_DPI;

src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFSheet.java

@@ -65,15 +65,22 @@ import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTWorksheet;
 public class SXSSFSheet implements Sheet
 {
     /*package*/ final XSSFSheet _sh;
-    private final SXSSFWorkbook _workbook;
+    protected final SXSSFWorkbook _workbook;
     private final TreeMap<Integer,SXSSFRow> _rows = new TreeMap<>();
-    private final SheetDataWriter _writer;
+    protected SheetDataWriter _writer;
     private int _randomAccessWindowSize = SXSSFWorkbook.DEFAULT_WINDOW_SIZE;
-    private final AutoSizeColumnTracker _autoSizeColumnTracker;
+    protected final AutoSizeColumnTracker _autoSizeColumnTracker;
     private int outlineLevelRow;
     private int lastFlushedRowNumber = -1;
     private boolean allFlushed;
 
+    protected SXSSFSheet(SXSSFWorkbook workbook, XSSFSheet xSheet, int randomAccessWindowSize) {
+        _workbook = workbook;
+        _sh = xSheet;
+        setRandomAccessWindowSize(randomAccessWindowSize);
+        _autoSizeColumnTracker = new AutoSizeColumnTracker(this);
+    }
+
     public SXSSFSheet(SXSSFWorkbook workbook, XSSFSheet xSheet) throws IOException {
         _workbook = workbook;
         _sh = xSheet;
@@ -1904,7 +1911,7 @@ public class SXSSFSheet implements Sheet
         if (!allFlushed) {
             flushRows();
         }
-        return _writer.dispose();
+        return _writer == null || _writer.dispose();
     }
 
     @Override

src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFWorkbook.java

@@ -96,13 +96,17 @@ public class SXSSFWorkbook implements Workbook {
     public static final int DEFAULT_WINDOW_SIZE = 100;
     private static final POILogger logger = POILogFactory.getLogger(SXSSFWorkbook.class);
 
-    private final XSSFWorkbook _wb;
+    protected final XSSFWorkbook _wb;
 
     private final Map<SXSSFSheet,XSSFSheet> _sxFromXHash = new HashMap<>();
     private final Map<XSSFSheet,SXSSFSheet> _xFromSxHash = new HashMap<>();
 
     private int _randomAccessWindowSize = DEFAULT_WINDOW_SIZE;
 
+    protected static interface ISheetInjector {
+        void writeSheetData(OutputStream out) throws IOException;
+    }
+
     /**
      * whether temp files should be compressed.
      */
@@ -111,12 +115,12 @@ public class SXSSFWorkbook implements Workbook {
     /**
      * shared string table - a cache of strings in this workbook
      */
-    private final SharedStringsTable _sharedStringSource;
+    protected final SharedStringsTable _sharedStringSource;
 
     /**
      * controls whether Zip64 mode is used - Always became the default in POI 5.0.0
      */
-    private Zip64Mode zip64Mode = Zip64Mode.Always;
+    protected Zip64Mode zip64Mode = Zip64Mode.Always;
 
     /**
      * Construct a new workbook with default row window size
@@ -285,7 +289,7 @@ public class SXSSFWorkbook implements Workbook {
         return _randomAccessWindowSize;
     }
 
-    private void setRandomAccessWindowSize(int rowAccessWindowSize) {
+    protected void setRandomAccessWindowSize(int rowAccessWindowSize) {
         if(rowAccessWindowSize == 0 || rowAccessWindowSize < -1) {
             throw new IllegalArgumentException("rowAccessWindowSize must be greater than 0 or -1");
         }
@@ -377,7 +381,7 @@ public class SXSSFWorkbook implements Workbook {
         _xFromSxHash.remove(xSheet);
     }
 
-    private XSSFSheet getSheetFromZipEntryName(String sheetRef)
+    protected XSSFSheet getSheetFromZipEntryName(String sheetRef)
     {
         for(XSSFSheet sheet : _sxFromXHash.values())
         {
@@ -408,9 +412,7 @@ public class SXSSFWorkbook implements Workbook {
                     // See bug 56557, we should not inject data into the special ChartSheets
                     if (xSheet != null && !(xSheet instanceof XSSFChartSheet)) {
                         SXSSFSheet sxSheet = getSXSSFSheet(xSheet);
-                        try (InputStream xis = sxSheet.getWorksheetXMLInputStream()) {
+                        copyStreamAndInjectWorksheet(is, zos, createSheetInjector(sxSheet));
-                            copyStreamAndInjectWorksheet(is, zos, xis);
-                        }
                     } else {
                         IOUtils.copy(is, zos);
                     }
@@ -434,7 +436,17 @@ public class SXSSFWorkbook implements Workbook {
         }
     }
 
-    private static void copyStreamAndInjectWorksheet(InputStream in, OutputStream out, InputStream worksheetData) throws IOException {
+    protected ISheetInjector createSheetInjector(SXSSFSheet sxSheet) throws IOException {
+        return (output) -> {
+            try (InputStream xis = sxSheet.getWorksheetXMLInputStream()) {
+                // Copy the worksheet data to "output".
+                IOUtils.copy(xis, output);
+            }
+        };
+    }
+
+    // private static void copyStreamAndInjectWorksheet(InputStream in, OutputStream out, InputStream worksheetData) throws IOException {
+    private static void copyStreamAndInjectWorksheet(InputStream in, OutputStream out, ISheetInjector sheetInjector) throws IOException {
         InputStreamReader inReader = new InputStreamReader(in, StandardCharsets.UTF_8);
         OutputStreamWriter outWriter = new OutputStreamWriter(out, StandardCharsets.UTF_8);
         boolean needsStartTag = true;
@@ -526,8 +538,7 @@ public class SXSSFWorkbook implements Workbook {
             outWriter.write("<sheetData>\n");
             outWriter.flush();
         }
-        //Copy the worksheet data to "out".
+        sheetInjector.writeSheetData(out);
-        IOUtils.copy(worksheetData,out);
         outWriter.write("</sheetData>");
         outWriter.flush();
         //Copy the rest of "in" to "out".
@@ -918,7 +929,8 @@ public class SXSSFWorkbook implements Workbook {
         for (SXSSFSheet sheet : _xFromSxHash.values())
         {
             try {
-                sheet.getSheetDataWriter().close();
+                SheetDataWriter _writer = sheet.getSheetDataWriter();
+                if (_writer != null) _writer.close();
             } catch (IOException e) {
                 logger.log(POILogger.WARN,
                         "An exception occurred while closing sheet data writer for sheet "

src/ooxml/java/org/apache/poi/xssf/streaming/SheetDataWriter.java

@@ -55,7 +55,7 @@ public class SheetDataWriter implements Closeable {
     private static final POILogger logger = POILogFactory.getLogger(SheetDataWriter.class);
 
     private final File _fd;
-    private final Writer _out;
+    protected final Writer _out;
     private int _rownum;
     private int _numberOfFlushedRows;
     private int _lowestIndexOfFlushedRows; // meaningful only of _numberOfFlushedRows>0
@@ -73,6 +73,11 @@ public class SheetDataWriter implements Closeable {
         _out = createWriter(_fd);
     }
     
+    public SheetDataWriter(Writer writer) throws IOException {
+        _fd = null;
+        _out = writer;
+    }
+
     public SheetDataWriter(SharedStringsTable sharedStringsTable) throws IOException {
         this();
         this._sharedStringSource = sharedStringsTable;

src/ooxml/java/org/apache/poi/xssf/streaming/StreamingSheetWriter.java

@@ -0,0 +1,84 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.xssf.streaming;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+
+import org.apache.poi.util.Beta;
+import org.apache.poi.util.POILogFactory;
+import org.apache.poi.util.POILogger;
+
+/**
+ * Unlike SheetDataWriter, this writer does not create a temporary file, it writes data directly
+ * to the provided OutputStream.
+ * @since 5.0.0
+ */
+@Beta
+public class StreamingSheetWriter extends SheetDataWriter {
+    private static final POILogger logger = POILogFactory.getLogger(StreamingSheetWriter.class);
+    
+    public StreamingSheetWriter() throws IOException {
+        throw new RuntimeException("StreamingSheetWriter requires OutputStream");
+    }
+    
+    public StreamingSheetWriter(OutputStream out) throws IOException {
+        super(createWriter(out));
+        logger.log(POILogger.DEBUG, "Preparing SSXSSF sheet writer");
+    }
+    
+    @Override
+    public File createTempFile() throws IOException {
+        throw new RuntimeException("Not supported with StreamingSheetWriter");
+    }
+    
+    @Override
+    public Writer createWriter(File fd) throws IOException {
+        throw new RuntimeException("Not supported with StreamingSheetWriter");
+    }
+    
+    /**
+     * Create a writer for the sheet data.
+     * 
+     * @param out the output stream to write to
+     */
+    protected static Writer createWriter(OutputStream out) throws IOException {
+        return new BufferedWriter(new OutputStreamWriter(out, "UTF-8"));
+    }
+    
+    @Override
+    public void close() throws IOException {
+        _out.flush();
+    }
+    
+    @Override
+    public InputStream getWorksheetXMLInputStream() throws IOException {
+        throw new RuntimeException("Not supported with StreamingSheetWriter");
+    }
+    
+    @Override
+    boolean dispose() throws IOException {
+        _out.close();
+        return true;
+    }
+}

src/ooxml/testcases/org/apache/poi/xssf/streaming/TestEmittingSXSSFWorkbook.java

@@ -0,0 +1,488 @@
+/*
+ *  ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one or more
+ *    contributor license agreements.  See the NOTICE file distributed with
+ *    this work for additional information regarding copyright ownership.
+ *    The ASF licenses this file to You under the Apache License, Version 2.0
+ *    (the "License"); you may not use this file except in compliance with
+ *    the License.  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ * ====================================================================
+ */
+
+package org.apache.poi.xssf.streaming;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.Arrays;
+
+import org.apache.poi.POIDataSamples;
+import org.apache.poi.openxml4j.opc.OPCPackage;
+import org.apache.poi.openxml4j.opc.PackageAccess;
+import org.apache.poi.ss.usermodel.BaseTestXWorkbook;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellType;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.usermodel.WorkbookFactory;
+import org.apache.poi.ss.util.CellReference;
+import org.apache.poi.util.NullOutputStream;
+import org.apache.poi.xssf.SXSSFITestDataProvider;
+import org.apache.poi.xssf.XSSFTestDataSamples;
+import org.apache.poi.xssf.usermodel.XSSFCell;
+import org.apache.poi.xssf.usermodel.XSSFRow;
+import org.apache.poi.xssf.usermodel.XSSFSheet;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
+import org.junit.After;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public final class TestEmittingSXSSFWorkbook extends BaseTestXWorkbook {
+    
+    public TestEmittingSXSSFWorkbook() {
+        super(SXSSFITestDataProvider.instance);
+    }
+    
+    @After
+    public void tearDown() {
+        ((SXSSFITestDataProvider) _testDataProvider).cleanup();
+    }
+    
+    /**
+     * cloning of sheets is not supported in SXSSF
+     */
+    @Override
+    @Test
+    public void cloneSheet() throws IOException {
+        try {
+            super.cloneSheet();
+            fail("expected exception");
+        } catch (RuntimeException e) {
+            assertEquals("Not Implemented", e.getMessage());
+        }
+    }
+    
+    /**
+     * cloning of sheets is not supported in SXSSF
+     */
+    @Override
+    @Test
+    public void sheetClone() throws IOException {
+        try {
+            super.sheetClone();
+            fail("expected exception");
+        } catch (RuntimeException e) {
+            assertEquals("Not Implemented", e.getMessage());
+        }
+    }
+    
+    /**
+     * Skip this test, as SXSSF doesn't update formulas on sheet name changes.
+     */
+    @Override
+    @Ignore("SXSSF doesn't update formulas on sheet name changes, as most cells probably aren't in memory at the time")
+    @Test
+    public void setSheetName() {
+    }
+    
+    @Test
+    public void existingWorkbook() throws IOException {
+        XSSFWorkbook xssfWb1 = new XSSFWorkbook();
+        xssfWb1.createSheet("S1");
+        EmittingSXSSFWorkbook wb1 = new EmittingSXSSFWorkbook(xssfWb1);
+        XSSFWorkbook xssfWb2 = SXSSFITestDataProvider.instance.writeOutAndReadBack(wb1);
+        assertTrue(wb1.dispose());
+        
+        EmittingSXSSFWorkbook wb2 = new EmittingSXSSFWorkbook(xssfWb2);
+        assertEquals(1, wb2.getNumberOfSheets());
+        Sheet sheet = wb2.getStreamingSheetAt(0);
+        assertNotNull(sheet);
+        assertEquals("S1", sheet.getSheetName());
+        assertTrue(wb2.dispose());
+        xssfWb2.close();
+        xssfWb1.close();
+        
+        wb2.close();
+        wb1.close();
+    }
+    
+    @Test
+    public void useSharedStringsTable() throws Exception {
+        // not supported with EmittingSXSSF
+    }
+    
+    @Test
+    public void addToExistingWorkbook() throws IOException {
+        XSSFWorkbook xssfWb1 = new XSSFWorkbook();
+        xssfWb1.createSheet("S1");
+        Sheet sheet = xssfWb1.createSheet("S2");
+        Row row = sheet.createRow(1);
+        Cell cell = row.createCell(1);
+        cell.setCellValue("value 2_1_1");
+        EmittingSXSSFWorkbook wb1 = new EmittingSXSSFWorkbook(xssfWb1);
+        XSSFWorkbook xssfWb2 = SXSSFITestDataProvider.instance.writeOutAndReadBack(wb1);
+        assertTrue(wb1.dispose());
+        xssfWb1.close();
+        
+        EmittingSXSSFWorkbook wb2 = new EmittingSXSSFWorkbook(xssfWb2);
+        // Add a row to the existing empty sheet
+        EmittingSXSSFSheet ssheet1 = wb2.getStreamingSheetAt(0);
+        ssheet1.setRowGenerator((ssxSheet) -> {
+            Row row1_1 = ssxSheet.createRow(1);
+            Cell cell1_1_1 = row1_1.createCell(1);
+            cell1_1_1.setCellValue("value 1_1_1");
+        });
+        
+        // Add a row to the existing non-empty sheet
+        EmittingSXSSFSheet ssheet2 = wb2.getStreamingSheetAt(1);
+        ssheet2.setRowGenerator((ssxSheet) -> {
+            Row row2_2 = ssxSheet.createRow(2);
+            Cell cell2_2_1 = row2_2.createCell(1);
+            cell2_2_1.setCellValue("value 2_2_1");
+        });
+        // Add a sheet with one row
+        EmittingSXSSFSheet ssheet3 = wb2.createSheet("S3");
+        ssheet3.setRowGenerator((ssxSheet) -> {
+            Row row3_1 = ssxSheet.createRow(1);
+            Cell cell3_1_1 = row3_1.createCell(1);
+            cell3_1_1.setCellValue("value 3_1_1");
+        });
+        
+        XSSFWorkbook xssfWb3 = SXSSFITestDataProvider.instance.writeOutAndReadBack(wb2);
+        wb2.close();
+        
+        assertEquals(3, xssfWb3.getNumberOfSheets());
+        // Verify sheet 1
+        XSSFSheet sheet1 = xssfWb3.getSheetAt(0);
+        assertEquals("S1", sheet1.getSheetName());
+        assertEquals(1, sheet1.getPhysicalNumberOfRows());
+        XSSFRow row1_1 = sheet1.getRow(1);
+        assertNotNull(row1_1);
+        XSSFCell cell1_1_1 = row1_1.getCell(1);
+        assertNotNull(cell1_1_1);
+        assertEquals("value 1_1_1", cell1_1_1.getStringCellValue());
+        // Verify sheet 2
+        XSSFSheet sheet2 = xssfWb3.getSheetAt(1);
+        assertEquals("S2", sheet2.getSheetName());
+        assertEquals(2, sheet2.getPhysicalNumberOfRows());
+        Row row2_1 = sheet2.getRow(1);
+        assertNotNull(row2_1);
+        Cell cell2_1_1 = row2_1.getCell(1);
+        assertNotNull(cell2_1_1);
+        assertEquals("value 2_1_1", cell2_1_1.getStringCellValue());
+        XSSFRow row2_2 = sheet2.getRow(2);
+        assertNotNull(row2_2);
+        XSSFCell cell2_2_1 = row2_2.getCell(1);
+        assertNotNull(cell2_2_1);
+        assertEquals("value 2_2_1", cell2_2_1.getStringCellValue());
+        // Verify sheet 3
+        XSSFSheet sheet3 = xssfWb3.getSheetAt(2);
+        assertEquals("S3", sheet3.getSheetName());
+        assertEquals(1, sheet3.getPhysicalNumberOfRows());
+        XSSFRow row3_1 = sheet3.getRow(1);
+        assertNotNull(row3_1);
+        XSSFCell cell3_1_1 = row3_1.getCell(1);
+        assertNotNull(cell3_1_1);
+        assertEquals("value 3_1_1", cell3_1_1.getStringCellValue());
+        
+        xssfWb2.close();
+        xssfWb3.close();
+        wb1.close();
+    }
+    
+    @Test
+    public void sheetdataWriter() throws IOException {
+        EmittingSXSSFWorkbook wb = new EmittingSXSSFWorkbook();
+        SXSSFSheet sh = wb.createSheet();
+        assertSame(sh.getClass(), EmittingSXSSFSheet.class);
+        SheetDataWriter wr = sh.getSheetDataWriter();
+        assertNull(wr);
+        wb.close();
+    }
+    
+    @Test
+    public void gzipSheetdataWriter() throws IOException {
+        EmittingSXSSFWorkbook wb = new EmittingSXSSFWorkbook();
+        wb.setCompressTempFiles(true);
+        
+        final int rowNum = 1000;
+        final int sheetNum = 5;
+        populateData(wb, 1000, 5);
+        
+        XSSFWorkbook xwb = SXSSFITestDataProvider.instance.writeOutAndReadBack(wb);
+        for (int i = 0; i < sheetNum; i++) {
+            Sheet sh = xwb.getSheetAt(i);
+            assertEquals("sheet" + i, sh.getSheetName());
+            for (int j = 0; j < rowNum; j++) {
+                Row row = sh.getRow(j);
+                assertNotNull("row[" + j + "]", row);
+                Cell cell1 = row.getCell(0);
+                assertEquals(new CellReference(cell1).formatAsString(), cell1.getStringCellValue());
+                
+                Cell cell2 = row.getCell(1);
+                assertEquals(i, (int) cell2.getNumericCellValue());
+                
+                Cell cell3 = row.getCell(2);
+                assertEquals(j, (int) cell3.getNumericCellValue());
+            }
+        }
+        
+        assertTrue(wb.dispose());
+        xwb.close();
+        wb.close();
+    }
+    
+    private static void assertWorkbookDispose(EmittingSXSSFWorkbook wb) {
+        populateData(wb, 1000, 5);
+        
+        for (Sheet sheet : wb) {
+            EmittingSXSSFSheet sxSheet = (EmittingSXSSFSheet) sheet;
+            assertNull(sxSheet.getSheetDataWriter());
+        }
+        
+        assertTrue(wb.dispose());
+        
+        for (Sheet sheet : wb) {
+            EmittingSXSSFSheet sxSheet = (EmittingSXSSFSheet) sheet;
+            assertNull(sxSheet.getSheetDataWriter());
+        }
+    }
+    
+    private static void populateData(EmittingSXSSFWorkbook wb, final int rowNum, final int sheetNum) {
+        for (int i = 0; i < sheetNum; i++) {
+            EmittingSXSSFSheet sheet = wb.createSheet("sheet" + i);
+            int index = i;
+            sheet.setRowGenerator((sh) -> {
+                for (int j = 0; j < rowNum; j++) {
+                    Row row = sh.createRow(j);
+                    Cell cell1 = row.createCell(0);
+                    cell1.setCellValue(new CellReference(cell1).formatAsString());
+                    
+                    Cell cell2 = row.createCell(1);
+                    cell2.setCellValue(index);
+                    
+                    Cell cell3 = row.createCell(2);
+                    cell3.setCellValue(j);
+                }
+            });
+        }
+    }
+    
+    @Test
+    public void workbookDispose() throws IOException {
+        EmittingSXSSFWorkbook wb1 = new EmittingSXSSFWorkbook();
+        // the underlying writer is SheetDataWriter
+        assertWorkbookDispose(wb1);
+        wb1.close();
+        
+        EmittingSXSSFWorkbook wb2 = new EmittingSXSSFWorkbook();
+        wb2.setCompressTempFiles(true);
+        // the underlying writer is GZIPSheetDataWriter
+        assertWorkbookDispose(wb2);
+        wb2.close();
+    }
+    
+    @Ignore("currently writing the same sheet multiple times is not supported...")
+    @Test
+    public void bug53515() throws Exception {
+        Workbook wb1 = new SXSSFWorkbook(10);
+        populateWorkbook(wb1);
+        saveTwice(wb1);
+        Workbook wb2 = new XSSFWorkbook();
+        populateWorkbook(wb2);
+        saveTwice(wb2);
+        wb2.close();
+        wb1.close();
+    }
+    
+    @Ignore("Crashes the JVM because of documented JVM behavior with concurrent writing/reading of zip-files, "
+            + "see http://www.oracle.com/technetwork/java/javase/documentation/overview-156328.html")
+    @Test
+    public void bug53515a() throws Exception {
+        File out = new File("Test.xlsx");
+        assertTrue(!out.exists() || out.delete());
+        for (int i = 0; i < 2; i++) {
+            final SXSSFWorkbook wb;
+            if (out.exists()) {
+                wb = new SXSSFWorkbook((XSSFWorkbook) WorkbookFactory.create(out));
+            } else {
+                wb = new SXSSFWorkbook(10);
+            }
+            
+            try {
+                FileOutputStream outSteam = new FileOutputStream(out);
+                if (i == 0) {
+                    populateWorkbook(wb);
+                } else {
+                    System.gc();
+                    System.gc();
+                    System.gc();
+                }
+                
+                wb.write(outSteam);
+                // assertTrue(wb.dispose());
+                outSteam.close();
+            } finally {
+                assertTrue(wb.dispose());
+            }
+            wb.close();
+        }
+        assertTrue(out.exists());
+        assertTrue(out.delete());
+    }
+    
+    private static void populateWorkbook(Workbook wb) {
+        Sheet sh = wb.createSheet();
+        for (int rownum = 0; rownum < 100; rownum++) {
+            Row row = sh.createRow(rownum);
+            for (int cellnum = 0; cellnum < 10; cellnum++) {
+                Cell cell = row.createCell(cellnum);
+                String address = new CellReference(cell).formatAsString();
+                cell.setCellValue(address);
+            }
+        }
+    }
+    
+    private static void saveTwice(Workbook wb) throws Exception {
+        for (int i = 0; i < 2; i++) {
+            try {
+                NullOutputStream out = new NullOutputStream();
+                wb.write(out);
+                out.close();
+            } catch (Exception e) {
+                throw new Exception("ERROR: failed on " + (i + 1) + "th time calling " + wb.getClass().getName()
+                        + ".write() with exception " + e.getMessage(), e);
+            }
+        }
+    }
+    
+    @Test
+    public void closeDoesNotModifyWorkbook() throws IOException {
+        final String filename = "SampleSS.xlsx";
+        final File file = POIDataSamples.getSpreadSheetInstance().getFile(filename);
+        
+        // Some tests commented out because close() modifies the file
+        // See bug 58779
+        
+        // String
+        // wb = new SXSSFWorkbook(new XSSFWorkbook(file.getPath()));
+        // assertCloseDoesNotModifyFile(filename, wb);
+        
+        // File
+        // wb = new SXSSFWorkbook(new XSSFWorkbook(file));
+        // assertCloseDoesNotModifyFile(filename, wb);
+        
+        // InputStream
+        
+        try (FileInputStream fis = new FileInputStream(file);
+                XSSFWorkbook xwb = new XSSFWorkbook(fis);
+                SXSSFWorkbook wb = new SXSSFWorkbook(xwb)) {
+            assertCloseDoesNotModifyFile(filename, wb);
+        }
+        
+        // OPCPackage
+        // wb = new SXSSFWorkbook(new XSSFWorkbook(OPCPackage.open(file)));
+        // assertCloseDoesNotModifyFile(filename, wb);
+    }
+    
+    /**
+     * Bug #59743
+     * 
+     * this is only triggered on other files apart of sheet[1,2,...].xml as those are either copied uncompressed or with
+     * the use of GZIPInputStream so we use shared strings
+     */
+    @Test
+    public void testZipBombNotTriggeredOnUselessContent() throws IOException {
+        SXSSFWorkbook swb = new SXSSFWorkbook(null, 1, true, true);
+        SXSSFSheet s = swb.createSheet();
+        char[] useless = new char[32767];
+        Arrays.fill(useless, ' ');
+        
+        for (int row = 0; row < 1; row++) {
+            Row r = s.createRow(row);
+            for (int col = 0; col < 10; col++) {
+                char[] prefix = Integer.toHexString(row * 1000 + col).toCharArray();
+                Arrays.fill(useless, 0, 10, ' ');
+                System.arraycopy(prefix, 0, useless, 0, prefix.length);
+                String ul = new String(useless);
+                r.createCell(col, CellType.STRING).setCellValue(ul);
+            }
+        }
+        
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        swb.write(bos);
+        swb.dispose();
+        swb.close();
+    }
+    
+    /**
+     * To avoid accident changes to the template, you should be able to create a SXSSFWorkbook from a read-only XSSF
+     * one, then change + save that (only). See bug #60010 TODO Fix this to work!
+     */
+    @Test
+    @Ignore
+    public void createFromReadOnlyWorkbook() throws Exception {
+        String sheetName = "Test SXSSF";
+        File input = XSSFTestDataSamples.getSampleFile("sample.xlsx");
+        
+        try (OPCPackage pkg = OPCPackage.open(input, PackageAccess.READ)) {
+            ByteArrayOutputStream bos = new ByteArrayOutputStream();
+            try (XSSFWorkbook xssf = new XSSFWorkbook(pkg)) {
+                try (SXSSFWorkbook wb = new SXSSFWorkbook(xssf, 2)) {
+                    Sheet s = wb.createSheet(sheetName);
+                    for (int i = 0; i < 10; i++) {
+                        Row r = s.createRow(i);
+                        r.createCell(0).setCellValue(true);
+                        r.createCell(1).setCellValue(2.4);
+                        r.createCell(2).setCellValue("Test Row " + i);
+                    }
+                    assertEquals(10, s.getLastRowNum());
+                    
+                    wb.write(bos);
+                    wb.dispose();
+                }
+            }
+            
+            try (XSSFWorkbook xssf = new XSSFWorkbook(new ByteArrayInputStream(bos.toByteArray()))) {
+                Sheet s = xssf.getSheet(sheetName);
+                assertEquals(10, s.getLastRowNum());
+                assertTrue(s.getRow(0).getCell(0).getBooleanCellValue());
+                assertEquals("Test Row 9", s.getRow(9).getCell(2).getStringCellValue());
+            }
+        }
+    }
+    
+    @Test
+    public void test56557() throws IOException {
+        Workbook wb = XSSFTestDataSamples.openSampleWorkbook("56557.xlsx");
+        
+        // Using streaming XSSFWorkbook makes the output file invalid
+        wb = new SXSSFWorkbook(((XSSFWorkbook) wb));
+        
+        // Should not throw POIXMLException: java.io.IOException: Unable to parse xml bean when reading back
+        Workbook wbBack = XSSFTestDataSamples.writeOutAndReadBack(wb);
+        assertNotNull(wbBack);
+        wbBack.close();
+        
+        wb.close();
+    }
+}