/* ====================================================================
   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.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Spliterator;
import java.util.TreeMap;

import org.apache.poi.ss.SpreadsheetVersion;
import org.apache.poi.ss.usermodel.AutoFilter;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellRange;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.DataValidation;
import org.apache.poi.ss.usermodel.DataValidationHelper;
import org.apache.poi.ss.usermodel.Footer;
import org.apache.poi.ss.usermodel.Header;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.PrintSetup;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.SheetConditionalFormatting;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellAddress;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.PaneInformation;
import org.apache.poi.ss.util.SheetUtil;
import org.apache.poi.util.Internal;
import org.apache.poi.util.NotImplemented;
import org.apache.poi.xssf.usermodel.*;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTColor;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTSheetFormatPr;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTSheetPr;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTSheetProtection;
import org.openxmlformats.schemas.spreadsheetml.x2006.main.CTWorksheet;

/**
 * Streaming version of XSSFSheet implementing the "BigGridDemo" strategy.
 */
public class SXSSFSheet implements Sheet, OoxmlSheetExtensions {
    /*package*/ final XSSFSheet _sh;
    protected final SXSSFWorkbook _workbook;
    private final TreeMap<Integer,SXSSFRow> _rows = new TreeMap<>();
    protected SheetDataWriter _writer;
    private int _randomAccessWindowSize = SXSSFWorkbook.DEFAULT_WINDOW_SIZE;
    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;
        _writer = workbook.createSheetDataWriter();
        setRandomAccessWindowSize(_workbook.getRandomAccessWindowSize());
        _autoSizeColumnTracker = new AutoSizeColumnTracker(this);
    }

    /**
     * for testing purposes only
     */
    @Internal
    SheetDataWriter getSheetDataWriter(){
        return _writer;
    }

    /* Gets "<sheetData>" document fragment*/
    public InputStream getWorksheetXMLInputStream() throws IOException {
        // flush all remaining data and close the temp file writer
        flushRows(0);
        _writer.close();
        return _writer.getWorksheetXMLInputStream();
    }

    //start of interface implementation
    /**
     * Create a new row within the sheet and return the high level representation
     *
     * @param rownum  row number
     * @return high level Row object representing a row in the sheet
     * @throws IllegalArgumentException If the max. number of rows is exceeded or
     *      a rownum is provided where the row is already flushed to disk.
     * @see #removeRow(Row)
     */
    @Override
    public SXSSFRow createRow(int rownum) {
        int maxrow = SpreadsheetVersion.EXCEL2007.getLastRowIndex();
        if (rownum < 0 || rownum > maxrow) {
            throw new IllegalArgumentException("Invalid row number (" + rownum
                    + ") outside allowable range (0.." + maxrow + ")");
        }

        // attempt to overwrite a row that is already flushed to disk
        if(_writer != null && rownum <= _writer.getLastFlushedRow() ) {
            throw new IllegalArgumentException(
                    "Attempting to write a row["+rownum+"] " +
                            "in the range [0," + _writer.getLastFlushedRow() + "] that is already written to disk.");
        }

        // attempt to overwrite a existing row in the input template
        if(_sh.getPhysicalNumberOfRows() > 0 && rownum <= _sh.getLastRowNum() ) {
            throw new IllegalArgumentException(
                    "Attempting to write a row["+rownum+"] " +
                            "in the range [0," + _sh.getLastRowNum() + "] that is already written to disk.");
        }

        SXSSFRow newRow = new SXSSFRow(this);
        newRow.setRowNumWithoutUpdatingSheet(rownum);
        _rows.put(rownum, newRow);
        allFlushed = false;
        if(_randomAccessWindowSize >= 0 && _rows.size() > _randomAccessWindowSize) {
            try {
                flushRows(_randomAccessWindowSize);
            } catch (IOException ioe) {
                throw new RuntimeException(ioe);
            }
        }
        return newRow;
    }

    /**
     * Remove a row from this sheet.  All cells contained in the row are removed as well
     *
     * @param row   representing a row to remove.
     */
    @Override
    public void removeRow(Row row) {
        if (row.getSheet() != this) {
            throw new IllegalArgumentException("Specified row does not belong to this sheet");
        }

        for(Iterator<Map.Entry<Integer, SXSSFRow>> iter = _rows.entrySet().iterator(); iter.hasNext();) {
            Map.Entry<Integer, SXSSFRow> entry = iter.next();
            if(entry.getValue() == row) {
                iter.remove();
                return;
            }
        }
    }

    /**
     * Returns the logical row (not physical) 0-based.  If you ask for a row that is not
     * defined you get a null.  This is to say row 4 represents the fifth row on a sheet.
     *
     * @param rownum  row to get (0-based)
     * @return Row representing the rownumber or null if its not defined on the sheet
     */
    @Override
    public SXSSFRow getRow(int rownum) {
        return _rows.get(rownum);
    }

    /**
     * Returns the number of physically defined rows (NOT the number of rows in the sheet)
     *
     * @return the number of physically defined rows in this sheet
     */
    @Override
    public int getPhysicalNumberOfRows() {
        return _rows.size() + _writer.getNumberOfFlushedRows();
    }

    /**
     * Gets the first row on the sheet
     *
     * @return the number of the first logical row on the sheet (0-based)
     */
    @Override
    public int getFirstRowNum() {
        if(_writer.getNumberOfFlushedRows() > 0) {
            return _writer.getLowestIndexOfFlushedRows();
        }
        return _rows.isEmpty() ? -1 : _rows.firstKey();
    }

    /**
     * Gets the last row on the sheet
     *
     * @return last row contained n this sheet (0-based)
     */
    @Override
    public int getLastRowNum() {
        return _rows.isEmpty() ? -1 : _rows.lastKey();
    }

    /**
     * Get the visibility state for a given column
     *
     * @param columnIndex - the column to get (0-based)
     * @param hidden - the visiblity state of the column
     */
    @Override
    public void setColumnHidden(int columnIndex, boolean hidden) {
        _sh.setColumnHidden(columnIndex,hidden);
    }

    /**
     * Get the hidden state for a given column
     *
     * @param columnIndex - the column to set (0-based)
     * @return hidden - <code>false</code> if the column is visible
     */
    @Override
    public boolean isColumnHidden(int columnIndex) {
        return _sh.isColumnHidden(columnIndex);
    }

    /**
     * Set the width (in units of 1/256th of a character width)
     * <p>
     * The maximum column width for an individual cell is 255 characters.
     * This value represents the number of characters that can be displayed
     * in a cell that is formatted with the standard font.
     * </p>
     *
     * @param columnIndex - the column to set (0-based)
     * @param width - the width in units of 1/256th of a character width
     */
    @Override
    public void setColumnWidth(int columnIndex, int width) {
        _sh.setColumnWidth(columnIndex,width);
    }

    /**
     * get the width (in units of 1/256th of a character width )
     * @param columnIndex - the column to set (0-based)
     * @return width - the width in units of 1/256th of a character width
     */
    @Override
    public int getColumnWidth(int columnIndex) {
        return _sh.getColumnWidth(columnIndex);
    }

    /**
     * Get the actual column width in pixels
     *
     * <p>
     * Please note, that this method works correctly only for workbooks
     * with the default font size (Calibri 11pt for .xlsx).
     * </p>
     */
    @Override
    public float getColumnWidthInPixels(int columnIndex) {
        return _sh.getColumnWidthInPixels(columnIndex);
    }

    /**
     * Set the default column width for the sheet (if the columns do not define their own width)
     * in characters
     *
     * @param width default column width measured in characters
     */
    @Override
    public void setDefaultColumnWidth(int width) {
        _sh.setDefaultColumnWidth(width);
    }

    /**
     * Get the default column width for the sheet (if the columns do not define their own width)
     * in characters
     *
     * @return default column width measured in characters
     */
    @Override
    public int getDefaultColumnWidth() {
        return _sh.getDefaultColumnWidth();
    }


    /**
     * Get the default row height for the sheet (if the rows do not define their own height) in
     * twips (1/20 of  a point)
     *
     * @return  default row height measured in twips (1/20 of  a point)
     */
    @Override
    public short getDefaultRowHeight() {
        return _sh.getDefaultRowHeight();
    }

    /**
     * Get the default row height for the sheet (if the rows do not define their own height) in
     * points.
     *
     * @return  default row height in points
     */
    @Override
    public float getDefaultRowHeightInPoints() {
        return _sh.getDefaultRowHeightInPoints();
    }

    /**
     * Set the default row height for the sheet (if the rows do not define their own height) in
     * twips (1/20 of  a point)
     *
     * @param  height default row height measured in twips (1/20 of  a point)
     */
    @Override
    public void setDefaultRowHeight(short height) {
        _sh.setDefaultRowHeight(height);
    }

    /**
     * Set the default row height for the sheet (if the rows do not define their own height) in
     * points
     * @param height default row height
     */
    @Override
    public void setDefaultRowHeightInPoints(float height) {
        _sh.setDefaultRowHeightInPoints(height);
    }


    /**
     * Get VML drawing for this sheet (aka 'legacy' drawing).
     *
     * @param autoCreate if true, then a new VML drawing part is created
     *
     * @return the VML drawing of {@code null} if the drawing was not found and autoCreate=false
     * @since POI 5.2.0
     */
    public XSSFVMLDrawing getVMLDrawing(boolean autoCreate) {
        XSSFSheet xssfSheet = getWorkbook().getXSSFSheet(this);
        return xssfSheet == null ? null : xssfSheet.getVMLDrawing(autoCreate);
    }

    /**
     * Returns the CellStyle that applies to the given
     *  (0 based) column, or null if no style has been
     *  set for that column
     */
    @Override
    public CellStyle getColumnStyle(int column) {
        return _sh.getColumnStyle(column);
    }

    /*
     * Sets the CellStyle that applies to the given
     *  (0 based) column.
     */
//    public CellStyle setColumnStyle(int column, CellStyle style);

    /**
     * Adds a merged region of cells (hence those cells form one)
     *
     * @param region (rowfrom/colfrom-rowto/colto) to merge
     * @return index of this region
     */
    @Override
    public int addMergedRegion(CellRangeAddress region) {
        return _sh.addMergedRegion(region);
    }

    /**
     * Adds a merged region of cells (hence those cells form one)
     *
     * @param region (rowfrom/colfrom-rowto/colto) to merge
     * @return index of this region
     */
    @Override
    public int addMergedRegionUnsafe(CellRangeAddress region) {
        return _sh.addMergedRegionUnsafe(region);
    }

    /**
     * Verify that merged regions do not intersect multi-cell array formulas and
     * no merged regions intersect another merged region in this sheet.
     *
     * @throws IllegalStateException if region intersects with a multi-cell array formula
     * @throws IllegalStateException if at least one region intersects with another merged region in this sheet
     */
    @Override
    public void validateMergedRegions() {
        _sh.validateMergedRegions();
    }

    /**
     * Determines whether the output is vertically centered on the page.
     *
     * @param value true to vertically center, false otherwise.
     */
    @Override
    public void setVerticallyCenter(boolean value) {
        _sh.setVerticallyCenter(value);
    }

    /**
     * Determines whether the output is horizontally centered on the page.
     *
     * @param value true to horizontally center, false otherwise.
     */
    @Override
    public void setHorizontallyCenter(boolean value) {
        _sh.setHorizontallyCenter(value);
    }

    /**
     * Determine whether printed output for this sheet will be horizontally centered.
     */
    @Override
    public boolean getHorizontallyCenter() {
        return _sh.getHorizontallyCenter();
    }

    /**
     * Determine whether printed output for this sheet will be vertically centered.
     */
    @Override
    public boolean getVerticallyCenter() {
        return _sh.getVerticallyCenter();
    }

    /**
     * Removes a merged region of cells (hence letting them free)
     *
     * @param index of the region to unmerge
     */
    @Override
    public void removeMergedRegion(int index) {
        _sh.removeMergedRegion(index);
    }

    /**
     * Removes a merged region of cells (hence letting them free)
     *
     * @param indices of the regions to unmerge
     */
    @Override
    public void removeMergedRegions(Collection<Integer> indices) {
        _sh.removeMergedRegions(indices);
    }

    /**
     * Returns the number of merged regions
     *
     * @return number of merged regions
     */
    @Override
    public int getNumMergedRegions() {
        return _sh.getNumMergedRegions();
    }

    /**
     * Returns the merged region at the specified index. If you want multiple
     * regions, it is faster to call {@link #getMergedRegions()} than to call
     * this each time.
     *
     * @return the merged region at the specified index
     */
    @Override
    public CellRangeAddress getMergedRegion(int index) {
        return _sh.getMergedRegion(index);
    }

    /**
     * Returns the list of merged regions. If you want multiple regions, this is
     * faster than calling {@link #getMergedRegion(int)} each time.
     *
     * @return the list of merged regions
     */
    @Override
    public List<CellRangeAddress> getMergedRegions() {
        return _sh.getMergedRegions();
    }

    /**
     *  Returns an iterator of the physical rows
     *
     * @return an iterator of the PHYSICAL rows.  Meaning the 3rd element may not
     * be the third row if say for instance the second row is undefined.
     */
    @Override
    public Iterator<Row> rowIterator() {
        @SuppressWarnings("unchecked")
        Iterator<Row> result = (Iterator<Row>)(Iterator<? extends Row>)_rows.values().iterator();
        return result;
    }

    /**
     *  Returns a spliterator of the physical rows
     *
     * @return a spliterator of the PHYSICAL rows.  Meaning the 3rd element may not
     * be the third row if say for instance the second row is undefined.
     *
     * @since POI 5.2.0
     */
    @Override
    @SuppressWarnings("unchecked")
    public Spliterator<Row> spliterator() {
        return (Spliterator<Row>)(Spliterator<? extends Row>) _rows.values().spliterator();
    }

    /**
     * Flag indicating whether the sheet displays Automatic Page Breaks.
     *
     * @param value <code>true</code> if the sheet displays Automatic Page Breaks.
     */
    @Override
    public void setAutobreaks(boolean value) {
        _sh.setAutobreaks(value);
    }

    /**
     * Set whether to display the guts or not
     *
     * @param value - guts or no guts
     */
    @Override
    public void setDisplayGuts(boolean value) {
        _sh.setDisplayGuts(value);
    }

    /**
     * Set whether the window should show 0 (zero) in cells containing zero value.
     * When false, cells with zero value appear blank instead of showing the number zero.
     *
     * @param value whether to display or hide all zero values on the worksheet
     */
    @Override
    public void setDisplayZeros(boolean value) {
        _sh.setDisplayZeros(value);
    }


    /**
     * Gets the flag indicating whether the window should show 0 (zero) in cells containing zero value.
     * When false, cells with zero value appear blank instead of showing the number zero.
     *
     * @return whether all zero values on the worksheet are displayed
     */
    @Override
    public boolean isDisplayZeros() {
        return _sh.isDisplayZeros();
    }

    /**
     * Sets whether the worksheet is displayed from right to left instead of from left to right.
     *
     * @param value true for right to left, false otherwise.
     */
    @Override
    public void setRightToLeft(boolean value) {
        _sh.setRightToLeft(value);
    }

    /**
     * Whether the text is displayed in right-to-left mode in the window
     *
     * @return whether the text is displayed in right-to-left mode in the window
     */
    @Override
    public boolean isRightToLeft() {
        return _sh.isRightToLeft();
    }

    /**
     * Flag indicating whether the Fit to Page print option is enabled.
     *
     * @param value <code>true</code> if the Fit to Page print option is enabled.
     */
    @Override
    public void setFitToPage(boolean value) {
        _sh.setFitToPage(value);
    }

    /**
     * Flag indicating whether summary rows appear below detail in an outline, when applying an outline.
     *
     * <p>
     * When true a summary row is inserted below the detailed data being summarized and a
     * new outline level is established on that row.
     * </p>
     * <p>
     * When false a summary row is inserted above the detailed data being summarized and a new outline level
     * is established on that row.
     * </p>
     * @param value <code>true</code> if row summaries appear below detail in the outline
     */
    @Override
    public void setRowSumsBelow(boolean value) {
        _sh.setRowSumsBelow(value);
    }

    /**
     * Flag indicating whether summary columns appear to the right of detail in an outline, when applying an outline.
     *
     * <p>
     * When true a summary column is inserted to the right of the detailed data being summarized
     * and a new outline level is established on that column.
     * </p>
     * <p>
     * When false a summary column is inserted to the left of the detailed data being
     * summarized and a new outline level is established on that column.
     * </p>
     * @param value <code>true</code> if col summaries appear right of the detail in the outline
     */
    @Override
    public void setRowSumsRight(boolean value) {
        _sh.setRowSumsRight(value);
    }

    /**
     * Flag indicating whether the sheet displays Automatic Page Breaks.
     *
     * @return <code>true</code> if the sheet displays Automatic Page Breaks.
     */
    @Override
    public boolean getAutobreaks() {
        return _sh.getAutobreaks();
    }

    /**
     * Get whether to display the guts or not,
     * default value is true
     *
     * @return boolean - guts or no guts
     */
    @Override
    public boolean getDisplayGuts() {
        return _sh.getDisplayGuts();
    }

    /**
     * Flag indicating whether the Fit to Page print option is enabled.
     *
     * @return <code>true</code> if the Fit to Page print option is enabled.
     */
    @Override
    public boolean getFitToPage() {
        return _sh.getFitToPage();
    }

    /**
     * Flag indicating whether summary rows appear below detail in an outline, when applying an outline.
     *
     * <p>
     * When true a summary row is inserted below the detailed data being summarized and a
     * new outline level is established on that row.
     * </p>
     * <p>
     * When false a summary row is inserted above the detailed data being summarized and a new outline level
     * is established on that row.
     * </p>
     * @return <code>true</code> if row summaries appear below detail in the outline
     */
    @Override
    public boolean getRowSumsBelow() {
        return _sh.getRowSumsBelow();
    }

    /**
     * Flag indicating whether summary columns appear to the right of detail in an outline, when applying an outline.
     *
     * <p>
     * When true a summary column is inserted to the right of the detailed data being summarized
     * and a new outline level is established on that column.
     * </p>
     * <p>
     * When false a summary column is inserted to the left of the detailed data being
     * summarized and a new outline level is established on that column.
     * </p>
     * @return <code>true</code> if col summaries appear right of the detail in the outline
     */
    @Override
    public boolean getRowSumsRight() {
        return _sh.getRowSumsRight();
    }

    /**
     * Returns whether gridlines are printed.
     *
     * @return whether gridlines are printed
     */
    @Override
    public boolean isPrintGridlines() {
        return _sh.isPrintGridlines();
    }

    /**
     * Turns on or off the printing of gridlines.
     *
     * @param show boolean to turn on or off the printing of gridlines
     */
    @Override
    public void setPrintGridlines(boolean show) {
        _sh.setPrintGridlines(show);
    }

    /**
     * Returns whether row and column headings are printed.
     *
     * @return whether row and column headings are printed
     */
    @Override
    public boolean isPrintRowAndColumnHeadings() {
        return _sh.isPrintRowAndColumnHeadings();
    }

    /**
     * Turns on or off the printing of row and column headings.
     *
     * @param show boolean to turn on or off the printing of row and column headings
     */
    @Override
    public void setPrintRowAndColumnHeadings(boolean show) {
        _sh.setPrintRowAndColumnHeadings(show);
    }

    /**
     * Gets the print setup object.
     *
     * @return The user model for the print setup object.
     */
    @Override
    public PrintSetup getPrintSetup() {
        return _sh.getPrintSetup();
    }

    /**
     * Gets the user model for the default document header.
     * <p>
     * Note that XSSF offers more kinds of document headers than HSSF does
     * </p>
     * @return the document header. Never <code>null</code>
     */
    @Override
    public Header getHeader() {
        return _sh.getHeader();
    }

    /**
     * Gets the user model for the default document footer.
     * <p>
     * Note that XSSF offers more kinds of document footers than HSSF does.
     * </p>
     * @return the document footer. Never <code>null</code>
     */
    @Override
    public Footer getFooter() {
        return _sh.getFooter();
    }

    /**
     * Sets a flag indicating whether this sheet is selected.
     * <p>
     * Note: multiple sheets can be selected, but only one sheet can be active at one time.
     * </p>
     * @param value <code>true</code> if this sheet is selected
     * @see Workbook#setActiveSheet(int)
     */
    @Override
    public void setSelected(boolean value) {
        _sh.setSelected(value);
    }

    /**
     * Gets the size of the margin in inches.
     *
     * @param margin which margin to get
     * @return the size of the margin
     */
    @Override
    public double getMargin(short margin) {
        return _sh.getMargin(margin);
    }

    /**
     * Sets the size of the margin in inches.
     *
     * @param margin which margin to get
     * @param size the size of the margin
     */
    @Override
    public void setMargin(short margin, double size) {
        _sh.setMargin(margin,size);
    }

    /**
     * Answer whether protection is enabled or disabled
     *
     * @return true means protection enabled; false means protection disabled
     */
    @Override
    public boolean getProtect() {
        return _sh.getProtect();
    }

    /**
     * Sets the protection enabled as well as the password
     * @param password to set for protection. Pass <code>null</code> to remove protection
     */
    @Override
    public void protectSheet(String password) {
        _sh.protectSheet(password);
    }

    /**
     * Answer whether scenario protection is enabled or disabled
     *
     * @return true means protection enabled; false means protection disabled
     */
    @Override
    public boolean getScenarioProtect() {
        return _sh.getScenarioProtect();
    }

    /**
     * Window zoom magnification for current view representing percent values.
     * Valid values range from 10 to 400. Horizontal and Vertical scale together.
     *
     * For example:
     * <pre>
     * 10 - 10%
     * 20 - 20%
     * ...
     * 100 - 100%
     * ...
     * 400 - 400%
     * </pre>
     *
     * Current view can be Normal, Page Layout, or Page Break Preview.
     *
     * @param scale window zoom magnification
     * @throws IllegalArgumentException if scale is invalid
     */
    @Override
    public void setZoom(int scale) {
        _sh.setZoom(scale);
    }

    /**
     * The top row in the visible view when the sheet is
     * first viewed after opening it in a viewer
     *
     * @return short indicating the rownum (0 based) of the top row
     */
    @Override
    public short getTopRow() {
        return _sh.getTopRow();
    }

    /**
     * The left col in the visible view when the sheet is
     * first viewed after opening it in a viewer
     *
     * @return short indicating the rownum (0 based) of the top row
     */
    @Override
    public short getLeftCol() {
        return _sh.getLeftCol();
    }

    /**
     * Sets desktop window pane display area, when the
     * file is first opened in a viewer.
     *
     * @param topRow the top row to show in desktop window pane
     * @param leftCol the left column to show in desktop window pane
     */
    @Override
    public void showInPane(int topRow, int leftCol) {
        _sh.showInPane(topRow, leftCol);
    }

    /**
     * Control if Excel should be asked to recalculate all formulas when the
     *  workbook is opened, via the "sheetCalcPr fullCalcOnLoad" option.
     *  Calculating the formula values with {@link org.apache.poi.ss.usermodel.FormulaEvaluator} is the
     *  recommended solution, but this may be used for certain cases where
     *  evaluation in POI is not possible.
     */
    @Override
    public void setForceFormulaRecalculation(boolean value) {
        _sh.setForceFormulaRecalculation(value);
    }

    /**
     * Whether Excel will be asked to recalculate all formulas when the
     *  workbook is opened.
     */
    @Override
    public boolean getForceFormulaRecalculation() {
        return _sh.getForceFormulaRecalculation();
    }

    /**
     * <i>Not implemented for SXSSFSheets</i>
     *
     * Shifts rows between startRow and endRow n number of rows.
     * If you use a negative number, it will shift rows up.
     * Code ensures that rows don't wrap around.
     *
     * Calls shiftRows(startRow, endRow, n, false, false);
     *
     * <p>
     * Additionally shifts merged regions that are completely defined in these
     * rows (ie. merged 2 cells on a row to be shifted).
     * @param startRow the row to start shifting
     * @param endRow the row to end shifting
     * @param n the number of rows to shift
     */
    @NotImplemented
    @Override
    public void shiftRows(int startRow, int endRow, int n) {
        throw new RuntimeException("Not Implemented");
    }

    /**
     * <i>Not implemented for SXSSFSheets</i>
     *
     * Shifts rows between startRow and endRow n number of rows.
     * If you use a negative number, it will shift rows up.
     * Code ensures that rows don't wrap around
     *
     * <p>
     * Additionally shifts merged regions that are completely defined in these
     * rows (ie. merged 2 cells on a row to be shifted). All merged regions that are
     * completely overlaid by shifting will be deleted.
     *
     * @param startRow the row to start shifting
     * @param endRow the row to end shifting
     * @param n the number of rows to shift
     * @param copyRowHeight whether to copy the row height during the shift
     * @param resetOriginalRowHeight whether to set the original row's height to the default
     */
    @NotImplemented
    @Override
    public void shiftRows(int startRow, int endRow, int n, boolean copyRowHeight, boolean resetOriginalRowHeight) {
        throw new RuntimeException("Not Implemented");
    }

    /**
     * Creates a split (freezepane). Any existing freezepane or split pane is overwritten.
     * @param colSplit      Horizonatal position of split.
     * @param rowSplit      Vertical position of split.
     * @param leftmostColumn   Left column visible in right pane.
     * @param topRow        Top row visible in bottom pane
     */
    @Override
    public void createFreezePane(int colSplit, int rowSplit, int leftmostColumn, int topRow) {
        _sh.createFreezePane(colSplit, rowSplit, leftmostColumn, topRow);
    }

    /**
     * Creates a split (freezepane). Any existing freezepane or split pane is overwritten.
     * @param colSplit      Horizonatal position of split.
     * @param rowSplit      Vertical position of split.
     */
    @Override
    public void createFreezePane(int colSplit, int rowSplit) {
        _sh.createFreezePane(colSplit,rowSplit);
    }

    /**
     * Creates a split pane. Any existing freezepane or split pane is overwritten.
     * @param xSplitPos      Horizonatal position of split (in 1/20th of a point).
     * @param ySplitPos      Vertical position of split (in 1/20th of a point).
     * @param topRow        Top row visible in bottom pane
     * @param leftmostColumn   Left column visible in right pane.
     * @param activePane    Active pane.  One of: PANE_LOWER_RIGHT,
     *                      PANE_UPPER_RIGHT, PANE_LOWER_LEFT, PANE_UPPER_LEFT
     * @see #PANE_LOWER_LEFT
     * @see #PANE_LOWER_RIGHT
     * @see #PANE_UPPER_LEFT
     * @see #PANE_UPPER_RIGHT
     */
    @Override
    public void createSplitPane(int xSplitPos, int ySplitPos, int leftmostColumn, int topRow, int activePane) {
        _sh.createSplitPane(xSplitPos, ySplitPos, leftmostColumn, topRow, activePane);
    }

    /**
     * Returns the information regarding the currently configured pane (split or freeze)
     *
     * @return null if no pane configured, or the pane information.
     */
    @Override
    public PaneInformation getPaneInformation() {
        return _sh.getPaneInformation();
    }

    /**
     * Sets whether the gridlines are shown in a viewer
     *
     * @param show whether to show gridlines or not
     */
    @Override
    public void setDisplayGridlines(boolean show) {
        _sh.setDisplayGridlines(show);
    }

    /**
     * Returns if gridlines are displayed
     *
     * @return whether gridlines are displayed
     */
    @Override
    public boolean isDisplayGridlines() {
        return _sh.isDisplayGridlines();
    }

    /**
     * Sets whether the formulas are shown in a viewer
     *
     * @param show whether to show formulas or not
     */
    @Override
    public void setDisplayFormulas(boolean show) {
        _sh.setDisplayFormulas(show);
    }

    /**
     * Returns if formulas are displayed
     *
     * @return whether formulas are displayed
     */
    @Override
    public boolean isDisplayFormulas() {
        return _sh.isDisplayFormulas();
    }

    /**
     * Sets whether the RowColHeadings are shown in a viewer
     *
     * @param show whether to show RowColHeadings or not
     */
    @Override
    public void setDisplayRowColHeadings(boolean show) {
        _sh.setDisplayRowColHeadings(show);
    }

    /**
     * Returns if RowColHeadings are displayed.
     * @return whether RowColHeadings are displayed
     */
    @Override
    public boolean isDisplayRowColHeadings() {
        return _sh.isDisplayRowColHeadings();
    }

    /**
     * Sets a page break at the indicated row
     * Breaks occur above the specified row and left of the specified column inclusive.
     *
     * For example, {@code sheet.setColumnBreak(2);} breaks the sheet into two parts
     * with columns A,B,C in the first and D,E,... in the second. Simuilar, {@code sheet.setRowBreak(2);}
     * breaks the sheet into two parts with first three rows (rownum=1...3) in the first part
     * and rows starting with rownum=4 in the second.
     *
     * @param row the row to break, inclusive
     */
    @Override
    public void setRowBreak(int row) {
        _sh.setRowBreak(row);
    }

    /**
     * Determines if there is a page break at the indicated row
     * @param row The row to check
     * @return true if there is a page-break at the given row, false otherwise
     */
    @Override
    public boolean isRowBroken(int row) {
        return _sh.isRowBroken(row);
    }

    /**
     * Removes the page break at the indicated row
     * @param row The row to remove page breaks from
     */
    @Override
    public void removeRowBreak(int row) {
        _sh.removeRowBreak(row);
    }

    /**
     * Retrieves all the horizontal page breaks
     * @return all the horizontal page breaks, or null if there are no row page breaks
     */
    @Override
    public int[] getRowBreaks() {
        return _sh.getRowBreaks();
    }

    /**
     * Retrieves all the vertical page breaks
     * @return all the vertical page breaks, or null if there are no column page breaks
     */
    @Override
    public int[] getColumnBreaks() {
        return _sh.getColumnBreaks();
    }

    /**
     * Sets a page break at the indicated column
     * @param column The column to work on
     */
    @Override
    public void setColumnBreak(int column) {
        _sh.setColumnBreak(column);
    }

    /**
     * Determines if there is a page break at the indicated column
     * @param column The column to check for page breaks
     * @return true if there is a page break at the given column, false otherwise
     */
    @Override
    public boolean isColumnBroken(int column) {
        return _sh.isColumnBroken(column);
    }

    /**
     * Removes a page break at the indicated column
     * @param column The column to remove a page break from
     */
    @Override
    public void removeColumnBreak(int column) {
        _sh.removeColumnBreak(column);
    }

    /**
     * Expands or collapses a column group.
     *
     * @param columnNumber      One of the columns in the group.
     * @param collapsed         true = collapse group, false = expand group.
     */
    @Override
    public void setColumnGroupCollapsed(int columnNumber, boolean collapsed) {
        _sh.setColumnGroupCollapsed(columnNumber, collapsed);
    }

    /**
     * Create an outline for the provided column range.
     *
     * @param fromColumn        beginning of the column range.
     * @param toColumn          end of the column range.
     */
    @Override
    public void groupColumn(int fromColumn, int toColumn) {
        _sh.groupColumn(fromColumn,toColumn);
    }

    /**
     * Ungroup a range of columns that were previously groupped
     *
     * @param fromColumn   start column (0-based)
     * @param toColumn     end column (0-based)
     */
    @Override
    public void ungroupColumn(int fromColumn, int toColumn) {
        _sh.ungroupColumn(fromColumn, toColumn);
    }

    /**
     * Tie a range of rows together so that they can be collapsed or expanded
     *
     * <p>
     *     Please note the rows being grouped <em>must</em> be in the current window,
     *     if the rows are already flushed then groupRow has no effect.
     * </p>
     *
     *      Correct code:
     *      <pre><code>
     *       Workbook wb = new SXSSFWorkbook(100);  // keep 100 rows in memory
     *       Sheet sh = wb.createSheet();
     *       for (int rownum = 0; rownum &lt; 1000; rownum++) {
     *           Row row = sh.createRow(rownum);
     *           if(rownum == 200)  {
     *               sh.groupRow(100, 200);
     *           }
     *       }
     *
     *      </code></pre>
     *
     *
     *      Incorrect code:
     *      <pre><code>
     *       Workbook wb = new SXSSFWorkbook(100);  // keep 100 rows in memory
     *       Sheet sh = wb.createSheet();
     *       for (int rownum = 0; rownum &lt; 1000; rownum++) {
     *           Row row = sh.createRow(rownum);
     *       }
     *       sh.groupRow(100, 200); // the rows in the range [100, 200] are already flushed and groupRows has no effect
     *
     *      </code></pre>
     *
     *
     * @param fromRow   start row (0-based)
     * @param toRow     end row (0-based)
     */
    @Override
    public void groupRow(int fromRow, int toRow) {
        for(SXSSFRow row : _rows.subMap(fromRow, toRow + 1).values()){
            int level = row.getOutlineLevel() + 1;
            row.setOutlineLevel(level);

            if(level > outlineLevelRow) {
                outlineLevelRow = level;
            }
        }

        setWorksheetOutlineLevelRow();
    }

    /**
     * Set row groupings (like groupRow) in a stream-friendly manner
     *
     * <p>
     *    groupRows requires all rows in the group to be in the current window.
     *    This is not always practical.  Instead use setRowOutlineLevel to
     *    explicitly set the group level.  Level 1 is the top level group,
     *    followed by 2, etc.  It is up to the user to ensure that level 2
     *    groups are correctly nested under level 1, etc.
     * </p>
     *
     * @param rownum    index of row to update (0-based)
     * @param level     outline level (greater than 0)
     */
    public void setRowOutlineLevel(int rownum, int level) {
        SXSSFRow row = _rows.get(rownum);
        row.setOutlineLevel(level);
        if(level > 0 && level > outlineLevelRow) {
            outlineLevelRow = level;
            setWorksheetOutlineLevelRow();
        }
    }

    private void setWorksheetOutlineLevelRow() {
        CTWorksheet ct = _sh.getCTWorksheet();
        CTSheetFormatPr pr = ct.isSetSheetFormatPr() ?
                ct.getSheetFormatPr() :
                ct.addNewSheetFormatPr();
        if(outlineLevelRow > 0) {
            pr.setOutlineLevelRow((short)outlineLevelRow);
        }
    }

    /**
     * Ungroup a range of rows that were previously groupped
     *
     * @param fromRow   start row (0-based)
     * @param toRow     end row (0-based)
     */
    @Override
    public void ungroupRow(int fromRow, int toRow) {
        _sh.ungroupRow(fromRow, toRow);
    }

    /**
     * Set view state of a grouped range of rows.
     *
     * <i>Not implemented for expanding (i.e. collapse == false)</i>
     *
     * @param row   start row of a groupped range of rows (0-based)
     * @param collapse whether to expand/collapse the detail rows
     * @throws RuntimeException if collapse is false as this is not implemented for SXSSF.
     */
    @Override
    public void setRowGroupCollapsed(int row, boolean collapse) {
        if (collapse) {
            collapseRow(row);
        } else {
            //expandRow(rowIndex);
            throw new RuntimeException("Unable to expand row: Not Implemented");
        }
    }

    /**
     * @param rowIndex the zero based row index to collapse
     */
    private void collapseRow(int rowIndex) {
        SXSSFRow row = getRow(rowIndex);
        if(row == null) {
            throw new IllegalArgumentException("Invalid row number("+ rowIndex + "). Row does not exist.");
        } else {
            int startRow = findStartOfRowOutlineGroup(rowIndex);

            // Hide all the columns until the end of the group
            int lastRow = writeHidden(row, startRow);
            SXSSFRow lastRowObj = getRow(lastRow);
            if (lastRowObj != null) {
                lastRowObj.setCollapsed(true);
            } else {
                SXSSFRow newRow = createRow(lastRow);
                newRow.setCollapsed(true);
            }
        }
    }

    /**
     * @param rowIndex the zero based row index to find from
     */
    private int findStartOfRowOutlineGroup(int rowIndex) {
        // Find the start of the group.
        Row row = getRow(rowIndex);
        int level = row.getOutlineLevel();
        if(level == 0) {
            throw new IllegalArgumentException("Outline level is zero for the row (" + rowIndex + ").");
        }
        int currentRow = rowIndex;
        while (getRow(currentRow) != null) {
            if (getRow(currentRow).getOutlineLevel() < level) {
                return currentRow + 1;
            }
            currentRow--;
        }
        return currentRow + 1;
    }

    private int writeHidden(SXSSFRow xRow, int rowIndex) {
        int level = xRow.getOutlineLevel();
        SXSSFRow currRow = getRow(rowIndex);

        while (currRow != null && currRow.getOutlineLevel() >= level) {
            currRow.setHidden(true);
            rowIndex++;
            currRow = getRow(rowIndex);
        }
        return rowIndex;
    }

    /**
     * Sets the default column style for a given column.  POI will only apply this style to new cells added to the sheet.
     *
     * @param column the column index
     * @param style the style to set
     */
    @Override
    public void setDefaultColumnStyle(int column, CellStyle style) {
        _sh.setDefaultColumnStyle(column, style);
    }


    /**
     * Track a column in the sheet for auto-sizing.
     * Note this has undefined behavior if a column is tracked after one or more rows are written to the sheet.
     * If <code>column</code> is already tracked, this call does nothing.
     *
     * @param column the column to track for auto-sizing
     * @since 3.14beta1
     * @see #trackColumnsForAutoSizing(Collection)
     * @see #trackAllColumnsForAutoSizing()
     */
    public void trackColumnForAutoSizing(int column) {
        _autoSizeColumnTracker.trackColumn(column);
    }

    /**
     * Track several columns in the sheet for auto-sizing.
     * Note this has undefined behavior if columns are tracked after one or more rows are written to the sheet.
     * Any column in <code>columns</code> that are already tracked are ignored by this call.
     *
     * @param columns the columns to track for auto-sizing
     * @since 3.14beta1
     */
    public void trackColumnsForAutoSizing(Collection<Integer> columns) {
        _autoSizeColumnTracker.trackColumns(columns);
    }

    /**
     * Tracks all columns in the sheet for auto-sizing. If this is called, individual columns do not need to be tracked.
     * Because determining the best-fit width for a cell is expensive, this may affect the performance.
     * @since 3.14beta1
     */
    public void trackAllColumnsForAutoSizing() {
        _autoSizeColumnTracker.trackAllColumns();
    }

    /**
     * Removes a column that was previously marked for inclusion in auto-size column tracking.
     * When a column is untracked, the best-fit width is forgotten.
     * If <code>column</code> is not tracked, it will be ignored by this call.
     *
     * @param column the index of the column to track for auto-sizing
     * @return true if column was tracked prior to this call, false if no action was taken
     * @since 3.14beta1
     * @see #untrackColumnsForAutoSizing(Collection)
     * @see #untrackAllColumnsForAutoSizing()
     */
    public boolean untrackColumnForAutoSizing(int column) {
        return _autoSizeColumnTracker.untrackColumn(column);
    }

    /**
     * Untracks several columns in the sheet for auto-sizing.
     * When a column is untracked, the best-fit width is forgotten.
     * Any column in <code>columns</code> that is not tracked will be ignored by this call.
     *
     * @param columns the indices of the columns to track for auto-sizing
     * @return true if one or more columns were untracked as a result of this call
     * @since 3.14beta1
     */
    public boolean untrackColumnsForAutoSizing(Collection<Integer> columns) {
        return _autoSizeColumnTracker.untrackColumns(columns);
    }

    /**
     * Untracks all columns in the sheet for auto-sizing. Best-fit column widths are forgotten.
     * If this is called, individual columns do not need to be untracked.
     * @since 3.14beta1
     */
    public void untrackAllColumnsForAutoSizing() {
        _autoSizeColumnTracker.untrackAllColumns();
    }

    /**
     * Returns true if column is currently tracked for auto-sizing.
     *
     * @param column the index of the column to check
     * @return true if column is tracked
     * @since 3.14beta1
     */
    public boolean isColumnTrackedForAutoSizing(int column) {
        return _autoSizeColumnTracker.isColumnTracked(column);
    }

    /**
     * Get the currently tracked columns for auto-sizing.
     * Note if all columns are tracked, this will only return the columns that have been explicitly or implicitly tracked,
     * which is probably only columns containing 1 or more non-blank values
     *
     * @return a set of the indices of all tracked columns
     * @since 3.14beta1
     */
    public Set<Integer> getTrackedColumnsForAutoSizing() {
        return _autoSizeColumnTracker.getTrackedColumns();
    }

    /**
     * Adjusts the column width to fit the contents.
     *
     * <p>
     * This process can be relatively slow on large sheets, so this should
     *  normally only be called once per column, at the end of your
     *  processing.
     * </p>
     * You can specify whether the content of merged cells should be considered or ignored.
     *  Default is to ignore merged cells.
     *
     *  <p>
     *  Special note about SXSSF implementation: You must register the columns you wish to track with
     *  the SXSSFSheet using {@link #trackColumnForAutoSizing(int)} or {@link #trackAllColumnsForAutoSizing()}.
     *  This is needed because the rows needed to compute the column width may have fallen outside the
     *  random access window and been flushed to disk.
     *  Tracking columns is required even if all rows are in the random access window.
     *  </p>
     *  <p><i>New in POI 3.14 beta 1: auto-sizes columns using cells from current and flushed rows.</i></p>
     *
     * @param column the column index to auto-size
     */
    @Override
    public void autoSizeColumn(int column) {
        autoSizeColumn(column, false);
    }

    /**
     * Adjusts the column width to fit the contents.
     * <p>
     * This process can be relatively slow on large sheets, so this should
     *  normally only be called once per column, at the end of your
     *  processing.
     * </p>
     * You can specify whether the content of merged cells should be considered or ignored.
     *  Default is to ignore merged cells.
     *
     *  <p>
     *  Special note about SXSSF implementation: You must register the columns you wish to track with
     *  the SXSSFSheet using {@link #trackColumnForAutoSizing(int)} or {@link #trackAllColumnsForAutoSizing()}.
     *  This is needed because the rows needed to compute the column width may have fallen outside the
     *  random access window and been flushed to disk.
     *  Tracking columns is required even if all rows are in the random access window.
     *  </p>
     *  <p><i>New in POI 3.14 beta 1: auto-sizes columns using cells from current and flushed rows.</i></p>
     *
     * @param column the column index to auto-size
     * @param useMergedCells whether to use the contents of merged cells when calculating the width of the column
     */
    @Override
    public void autoSizeColumn(int column, boolean useMergedCells) {
        // Multiple calls to autoSizeColumn need to look up the best-fit width
        // of rows already flushed to disk plus re-calculate the best-fit width
        // of rows in the current window. It isn't safe to update the column
        // widths before flushing to disk because columns in the random access
        // window rows may change in best-fit width. The best-fit width of a cell
        // is only fixed when it becomes inaccessible for modification.
        // Changes to the shared strings table, styles table, or formulas might
        // be able to invalidate the auto-size width without the opportunity
        // to recalculate the best-fit width for the flushed rows. This is an
        // inherent limitation of SXSSF. If having correct auto-sizing is
        // critical, the flushed rows would need to be re-read by the read-only
        // XSSF eventmodel (SAX) or the memory-heavy XSSF usermodel (DOM).
        final int flushedWidth;
        try {
            // get the best fit width of rows already flushed to disk
            flushedWidth = _autoSizeColumnTracker.getBestFitColumnWidth(column, useMergedCells);
        }
        catch (final IllegalStateException e) {
            throw new IllegalStateException("Could not auto-size column. Make sure the column was tracked prior to auto-sizing the column.", e);
        }

        // get the best-fit width of rows currently in the random access window
        final int activeWidth = (int) (256 * SheetUtil.getColumnWidth(this, column, useMergedCells));

        // the best-fit width for both flushed rows and random access window rows
        // flushedWidth or activeWidth may be negative if column contains only blank cells
        final int bestFitWidth = Math.max(flushedWidth,  activeWidth);

        if (bestFitWidth > 0) {
            final int maxColumnWidth = 255*256; // The maximum column width for an individual cell is 255 characters
            final int width = Math.min(bestFitWidth,  maxColumnWidth);
            setColumnWidth(column, width);
        }
    }

    /**
     * Returns cell comment for the specified row and column
     *
     * @return cell comment or <code>null</code> if not found
     */
    @Override
    public XSSFComment getCellComment(CellAddress ref) {
        return _sh.getCellComment(ref);
    }

    /**
     * Returns all cell comments on this sheet.
     * @return A map of each Comment in the sheet, keyed on the cell address where
     * the comment is located.
     */
    @Override
    public Map<CellAddress, XSSFComment> getCellComments() {
        return _sh.getCellComments();
    }

    /**
     * Get a Hyperlink in this sheet anchored at row, column
     *
     * @param row The 0-base row number
     * @param column The 0-based column number
     * @return hyperlink if there is a hyperlink anchored at row, column; otherwise returns null
     */
    @Override
    public XSSFHyperlink getHyperlink(int row, int column) {
        return _sh.getHyperlink(row, column);
    }

    /**
     * Get a Hyperlink in this sheet located in a cell specified by {code addr}
     *
     * @param addr The address of the cell containing the hyperlink
     * @return hyperlink if there is a hyperlink anchored at {@code addr}; otherwise returns {@code null}
     * @since POI 3.15 beta 3
     */
    @Override
    public XSSFHyperlink getHyperlink(CellAddress addr) {
        return _sh.getHyperlink(addr);
    }

    /**
     * Get a list of Hyperlinks in this sheet
     *
     * @return Hyperlinks for the sheet
     */
    @Override
    public List<XSSFHyperlink> getHyperlinkList() {
        return _sh.getHyperlinkList();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public XSSFDrawing getDrawingPatriarch() {
        return _sh.getDrawingPatriarch();
    }

    /**
     * Creates the top-level drawing patriarch.
     *
     * @return  The new drawing patriarch.
     */
    @Override
    public SXSSFDrawing createDrawingPatriarch() {
        return new SXSSFDrawing(getWorkbook(), _sh.createDrawingPatriarch());
    }


    /**
     * Return the parent workbook
     *
     * @return the parent workbook
     */
    @Override
    public SXSSFWorkbook getWorkbook() {
        return _workbook;
    }

    /**
     * Returns the name of this sheet
     *
     * @return the name of this sheet
     */
    @Override
    public String getSheetName() {
        return _sh.getSheetName();
    }

    /**
     * Note - this is not the same as whether the sheet is focused (isActive)
     * @return <code>true</code> if this sheet is currently selected
     */
    @Override
    public boolean isSelected() {
        return _sh.isSelected();
    }


    /**
     * Sets array formula to specified region for result.
     *
     * @param formula text representation of the formula
     * @param range Region of array formula for result.
     * @return the {@link CellRange} of cells affected by this change
     */
    @Override
    public CellRange<? extends Cell> setArrayFormula(String formula, CellRangeAddress range) {
        // the simple approach via _sh does not work as it creates rows in the XSSFSheet and thus causes
        // corrupted .xlsx files as rows appear multiple times in the resulting sheetX.xml files
        // return _sh.setArrayFormula(formula, range);

        throw new RuntimeException("Not Implemented");
    }

    /**
     * Remove a Array Formula from this sheet.  All cells contained in the Array Formula range are removed as well
     *
     * @param cell   any cell within Array Formula range
     * @return the {@link CellRange} of cells affected by this change
     */
    @Override
    public CellRange<? extends Cell> removeArrayFormula(Cell cell) {
        // the simple approach via _sh does not work as it creates rows in the XSSFSheet and thus causes
        // corrupted .xlsx files as rows appear multiple times in the resulting sheetX.xml files
        // return _sh.removeArrayFormula(cell);

        throw new RuntimeException("Not Implemented");
    }

    @Override
    public DataValidationHelper getDataValidationHelper() {
        return _sh.getDataValidationHelper();
    }

    @Override
    public List<XSSFDataValidation> getDataValidations() {
        return _sh.getDataValidations();
    }

    /**
     * Creates a data validation object
     * @param dataValidation The Data validation object settings
     */
    @Override
    public void addValidationData(DataValidation dataValidation) {
        _sh.addValidationData(dataValidation);
    }

    /**
     * Enable filtering for a range of cells
     *
     * @param range the range of cells to filter
     */
    @Override
    public AutoFilter setAutoFilter(CellRangeAddress range) {
        return _sh.setAutoFilter(range);
    }

    @Override
    public SheetConditionalFormatting getSheetConditionalFormatting(){
        return _sh.getSheetConditionalFormatting();
    }


    @Override
    public CellRangeAddress getRepeatingRows() {
        return _sh.getRepeatingRows();
    }

    @Override
    public CellRangeAddress getRepeatingColumns() {
        return _sh.getRepeatingColumns();
    }

    @Override
    public void setRepeatingRows(CellRangeAddress rowRangeRef) {
        _sh.setRepeatingRows(rowRangeRef);
    }

    @Override
    public void setRepeatingColumns(CellRangeAddress columnRangeRef) {
        _sh.setRepeatingColumns(columnRangeRef);
    }



//end of interface implementation
    /**
     * 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 exceed the specified value, then the
     * row with the lowest index value is flushed and cannot be accessed
     * via getRow() anymore.
     * 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.
     * A value of 0 is not allowed because it would flush any newly created row
     * without having a chance to specify any cells.
     */
    public void setRandomAccessWindowSize(int value) {
        if(value == 0 || value < -1) {
            throw new IllegalArgumentException("RandomAccessWindowSize must be either -1 or a positive integer");
        }
        _randomAccessWindowSize = value;
    }

    /**
     * Are all rows flushed to disk?
     */
    public boolean areAllRowsFlushed() {
        return allFlushed;
    }
    /**
     * @return Last row number to be flushed to disk, or -1 if none flushed yet
     */
    public int getLastFlushedRowNum() {
        return lastFlushedRowNumber;
    }

    /**
     * Specifies how many rows can be accessed at most via getRow().
     * The excess rows (if any) are flushed to the disk while rows
     * with lower index values are flushed first.
     */
    public void flushRows(int remaining) throws IOException {
        while(_rows.size() > remaining) {
            flushOneRow();
        }
        if (remaining == 0) {
            allFlushed = true;
        }
    }

    /**
     * Flush all rows to disk. After this call no rows can be accessed via getRow()
     *
     * @throws IOException If an I/O error occurs
     */
    public void flushRows() throws IOException {
        this.flushRows(0);
    }

    /**
     * Flush all the data in the buffered stream to the temp file.
     *
     * @throws IOException If an I/O error occurs
     */
    public void flushBufferedData() throws IOException {
        this._writer.flush();
    }

    private void flushOneRow() throws IOException {
        Integer firstRowNum = _rows.firstKey();
        if (firstRowNum!=null) {
            int rowIndex = firstRowNum;
            SXSSFRow row = _rows.get(firstRowNum);
            // Update the best fit column widths for auto-sizing just before the rows are flushed
            _autoSizeColumnTracker.updateColumnWidths(row);
            if (_writer != null) _writer.writeRow(rowIndex, row);
            _rows.remove(firstRowNum);
            lastFlushedRowNumber = rowIndex;
        }
    }

    public void changeRowNum(SXSSFRow row, int newRowNum) {
        removeRow(row);
        row.setRowNumWithoutUpdatingSheet(newRowNum);
        _rows.put(newRowNum, row);
    }

    public int getRowNum(SXSSFRow row) {
        return row.getRowNum();
    }

    /**
     * Deletes the temporary file that backed this sheet on disk.
     * @return true if the file was deleted, false if it wasn't.
     */
    boolean dispose() throws IOException {
        boolean ret;
        try {
            if (!allFlushed) {
                flushRows();
            }
        } finally {
            ret = _writer == null || _writer.dispose();
        }
        return ret;
    }

    @Override
    public int getColumnOutlineLevel(int columnIndex) {
        return _sh.getColumnOutlineLevel(columnIndex);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public CellAddress getActiveCell() {
        return _sh.getActiveCell();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setActiveCell(CellAddress address) {
        _sh.setActiveCell(address);
    }

    public XSSFColor getTabColor() {
        return _sh.getTabColor();
    }

    public void setTabColor(XSSFColor color) {
        _sh.setTabColor(color);
    }

    /**
     * Enable sheet protection
     */
    public void enableLocking() {
        safeGetProtectionField().setSheet(true);
    }

    /**
     * Disable sheet protection
     */
    public void disableLocking() {
        safeGetProtectionField().setSheet(false);
    }

    /**
     * Enable or disable Autofilters locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockAutoFilter(boolean enabled) {
        safeGetProtectionField().setAutoFilter(enabled);
    }

    /**
     * Enable or disable Deleting columns locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockDeleteColumns(boolean enabled) {
        safeGetProtectionField().setDeleteColumns(enabled);
    }

    /**
     * Enable or disable Deleting rows locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockDeleteRows(boolean enabled) {
        safeGetProtectionField().setDeleteRows(enabled);
    }

    /**
     * Enable or disable Formatting cells locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockFormatCells(boolean enabled) {
        safeGetProtectionField().setFormatCells(enabled);
    }

    /**
     * Enable or disable Formatting columns locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockFormatColumns(boolean enabled) {
        safeGetProtectionField().setFormatColumns(enabled);
    }

    /**
     * Enable or disable Formatting rows locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockFormatRows(boolean enabled) {
        safeGetProtectionField().setFormatRows(enabled);
    }

    /**
     * Enable or disable Inserting columns locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockInsertColumns(boolean enabled) {
        safeGetProtectionField().setInsertColumns(enabled);
    }

    /**
     * Enable or disable Inserting hyperlinks locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockInsertHyperlinks(boolean enabled) {
        safeGetProtectionField().setInsertHyperlinks(enabled);
    }

    /**
     * Enable or disable Inserting rows locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockInsertRows(boolean enabled) {
        safeGetProtectionField().setInsertRows(enabled);
    }

    /**
     * Enable or disable Pivot Tables locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockPivotTables(boolean enabled) {
        safeGetProtectionField().setPivotTables(enabled);
    }

    /**
     * Enable or disable Sort locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockSort(boolean enabled) {
        safeGetProtectionField().setSort(enabled);
    }

    /**
     * Enable or disable Objects locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockObjects(boolean enabled) {
        safeGetProtectionField().setObjects(enabled);
    }

    /**
     * Enable or disable Scenarios locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockScenarios(boolean enabled) {
        safeGetProtectionField().setScenarios(enabled);
    }

    /**
     * Enable or disable Selection of locked cells locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockSelectLockedCells(boolean enabled) {
        safeGetProtectionField().setSelectLockedCells(enabled);
    }

    /**
     * Enable or disable Selection of unlocked cells locking.
     * This does not modify sheet protection status.
     * To enforce this un-/locking, call {@link #disableLocking()} or {@link #enableLocking()}
     */
    public void lockSelectUnlockedCells(boolean enabled) {
        safeGetProtectionField().setSelectUnlockedCells(enabled);
    }


    private CTSheetProtection safeGetProtectionField() {
        CTWorksheet ct = _sh.getCTWorksheet();
        if (!isSheetProtectionEnabled()) {
            return ct.addNewSheetProtection();
        }
        return ct.getSheetProtection();
    }

    /* package */ boolean isSheetProtectionEnabled() {
        CTWorksheet ct = _sh.getCTWorksheet();
        return (ct.isSetSheetProtection());
    }

    /**
     * Set background color of the sheet tab
     *
     * @param colorIndex  the indexed color to set, must be a constant from {@link IndexedColors}
     */
    public void setTabColor(int colorIndex){
        CTWorksheet ct = _sh.getCTWorksheet();
        CTSheetPr pr = ct.getSheetPr();
        if(pr == null) pr = ct.addNewSheetPr();
        CTColor color = CTColor.Factory.newInstance();
        color.setIndexed(colorIndex);
        pr.setTabColor(color);
    }

    @NotImplemented
    @Override
    public void shiftColumns(int startColumn, int endColumn, int n){
        throw new UnsupportedOperationException("Not Implemented");
    }
}
