org.apache.poi.hssf.usermodel
Class HSSFFormulaEvaluator

java.lang.Object
  org.apache.poi.hssf.usermodel.HSSFFormulaEvaluator

All Implemented Interfaces:

FormulaEvaluator

public class HSSFFormulaEvaluator
extends java.lang.Object
implements FormulaEvaluator

Evaluates formula cells.

For performance reasons, this class keeps a cache of all previously calculated intermediate cell values. Be sure to call clearAllCachedResultValues() if any workbook cells are changed between calls to evaluate~ methods on this class.

Author:

Amol S. Deshmukh < amolweb at ya hoo dot com >, Josh Micich

Constructor Summary

HSSFFormulaEvaluator(HSSFSheet sheet, HSSFWorkbook workbook)
Deprecated. (Sep 2008) HSSFSheet parameter is ignored

HSSFFormulaEvaluator(HSSFWorkbook workbook)

HSSFFormulaEvaluator(HSSFWorkbook workbook, IStabilityClassifier stabilityClassifier)

Method Summary

void	clearAllCachedResultValues() Should be called whenever there are major changes (e.g.
static HSSFFormulaEvaluator	create(HSSFWorkbook workbook, IStabilityClassifier stabilityClassifier, UDFFinder udfFinder)
CellValue	evaluate(Cell cell) If cell contains a formula, the formula is evaluated and returned, else the CellValue simply copies the appropriate cell value from the cell and also its cell type.
void	evaluateAll() Loops over all cells in all sheets of the supplied workbook.
static void	evaluateAllFormulaCells(HSSFWorkbook wb) Loops over all cells in all sheets of the supplied workbook.
static void	evaluateAllFormulaCells(Workbook wb) Loops over all cells in all sheets of the supplied workbook.
int	evaluateFormulaCell(Cell cell) If cell contains formula, it evaluates the formula, and saves the result of the formula.
HSSFCell	evaluateInCell(Cell cell) If cell contains formula, it evaluates the formula, and puts the formula result back into the cell, in place of the old formula.
void	notifyDeleteCell(Cell cell) Should be called to tell the cell value cache that the specified cell has just become a formula cell, or the formula text has changed
void	notifyDeleteCell(HSSFCell cell) Should be called to tell the cell value cache that the specified cell has just been deleted.
void	notifySetFormula(Cell cell) Should be called to tell the cell value cache that the specified (value or formula) cell has changed.
void	notifyUpdateCell(Cell cell) Should be called to tell the cell value cache that the specified (value or formula) cell has changed.
void	notifyUpdateCell(HSSFCell cell) Should be called to tell the cell value cache that the specified (value or formula) cell has changed.
void	setCurrentRow(HSSFRow row) Deprecated. (Aug 2008) - not needed, since the current row can be derived from the cell
void	setIgnoreMissingWorkbooks(boolean ignore) Whether to ignore missing references to external workbooks and use cached formula results in the main workbook instead.
static void	setupEnvironment(java.lang.String[] workbookNames, HSSFFormulaEvaluator[] evaluators) Coordinates several formula evaluators together so that formulas that involve external references can be evaluated.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HSSFFormulaEvaluator

public HSSFFormulaEvaluator(HSSFSheet sheet,
                            HSSFWorkbook workbook)

Deprecated. (Sep 2008) HSSFSheet parameter is ignored

HSSFFormulaEvaluator

public HSSFFormulaEvaluator(HSSFWorkbook workbook)

HSSFFormulaEvaluator

public HSSFFormulaEvaluator(HSSFWorkbook workbook,
                            IStabilityClassifier stabilityClassifier)

Parameters:

stabilityClassifier - used to optimise caching performance. Pass null for the (conservative) assumption that any cell may have its definition changed after evaluation begins.

Method Detail

create

public static HSSFFormulaEvaluator create(HSSFWorkbook workbook,
                                          IStabilityClassifier stabilityClassifier,
                                          UDFFinder udfFinder)

Parameters:

stabilityClassifier - used to optimise caching performance. Pass null for the (conservative) assumption that any cell may have its definition changed after evaluation begins.

udfFinder - pass null for default (AnalysisToolPak only)

setupEnvironment

public static void setupEnvironment(java.lang.String[] workbookNames,
                                    HSSFFormulaEvaluator[] evaluators)

Coordinates several formula evaluators together so that formulas that involve external references can be evaluated.

Parameters:

workbookNames - the simple file names used to identify the workbooks in formulas with external links (for example "MyData.xls" as used in a formula "[MyData.xls]Sheet1!A1")

evaluators - all evaluators for the full set of workbooks required by the formulas.

setCurrentRow

public void setCurrentRow(HSSFRow row)

Deprecated. (Aug 2008) - not needed, since the current row can be derived from the cell

Does nothing

clearAllCachedResultValues

public void clearAllCachedResultValues()

Should be called whenever there are major changes (e.g. moving sheets) to input cells in the evaluated workbook. If performance is not critical, a single call to this method may be used instead of many specific calls to the notify~ methods. Failure to call this method after changing cell values will cause incorrect behaviour of the evaluate~ methods of this class

Specified by:

clearAllCachedResultValues in interface FormulaEvaluator

notifyUpdateCell

public void notifyUpdateCell(HSSFCell cell)

Should be called to tell the cell value cache that the specified (value or formula) cell has changed. Failure to call this method after changing cell values will cause incorrect behaviour of the evaluate~ methods of this class

notifyUpdateCell

public void notifyUpdateCell(Cell cell)

Description copied from interface: FormulaEvaluator

Should be called to tell the cell value cache that the specified (value or formula) cell has changed. Failure to call this method after changing cell values will cause incorrect behaviour of the evaluate~ methods of this class

Specified by:

notifyUpdateCell in interface FormulaEvaluator

notifyDeleteCell

public void notifyDeleteCell(HSSFCell cell)

Should be called to tell the cell value cache that the specified cell has just been deleted. Failure to call this method after changing cell values will cause incorrect behaviour of the evaluate~ methods of this class

notifyDeleteCell

public void notifyDeleteCell(Cell cell)

Description copied from interface: FormulaEvaluator

Should be called to tell the cell value cache that the specified cell has just become a formula cell, or the formula text has changed

Specified by:

notifyDeleteCell in interface FormulaEvaluator

notifySetFormula

public void notifySetFormula(Cell cell)

Should be called to tell the cell value cache that the specified (value or formula) cell has changed. Failure to call this method after changing cell values will cause incorrect behaviour of the evaluate~ methods of this class

Specified by:

notifySetFormula in interface FormulaEvaluator

evaluate

public CellValue evaluate(Cell cell)

If cell contains a formula, the formula is evaluated and returned, else the CellValue simply copies the appropriate cell value from the cell and also its cell type. This method should be preferred over evaluateInCell() when the call should not modify the contents of the original cell.

Specified by:

evaluate in interface FormulaEvaluator

Parameters:

cell - may be null signifying that the cell is not present (or blank)

Returns:

null if the supplied cell is null or blank

evaluateFormulaCell

public int evaluateFormulaCell(Cell cell)

If cell contains formula, it evaluates the formula, and saves the result of the formula. The cell remains as a formula cell. If the cell does not contain formula, this method returns -1 and leaves the cell unchanged. Note that the type of the formula result is returned, so you know what kind of cached formula result is also stored with the formula.

 int evaluatedCellType = evaluator.evaluateFormulaCell(cell);
 

Be aware that your cell will hold both the formula, and the result. If you want the cell replaced with the result of the formula, use evaluateInCell(org.apache.poi.ss.usermodel.Cell)

Specified by:

evaluateFormulaCell in interface FormulaEvaluator

Parameters:

cell - The cell to evaluate

Returns:

-1 for non-formula cells, or the type of the formula result

evaluateInCell

public HSSFCell evaluateInCell(Cell cell)

If cell contains formula, it evaluates the formula, and puts the formula result back into the cell, in place of the old formula. Else if cell does not contain formula, this method leaves the cell unchanged. Note that the same instance of HSSFCell is returned to allow chained calls like:

 int evaluatedCellType = evaluator.evaluateInCell(cell).getCellType();
 

Be aware that your cell value will be changed to hold the result of the formula. If you simply want the formula value computed for you, use evaluateFormulaCell(Cell)}

Specified by:

evaluateInCell in interface FormulaEvaluator

evaluateAllFormulaCells

public static void evaluateAllFormulaCells(HSSFWorkbook wb)

Loops over all cells in all sheets of the supplied workbook. For cells that contain formulas, their formulas are evaluated, and the results are saved. These cells remain as formula cells. For cells that do not contain formulas, no changes are made. This is a helpful wrapper around looping over all cells, and calling evaluateFormulaCell on each one.

evaluateAllFormulaCells

public static void evaluateAllFormulaCells(Workbook wb)

Loops over all cells in all sheets of the supplied workbook. For cells that contain formulas, their formulas are evaluated, and the results are saved. These cells remain as formula cells. For cells that do not contain formulas, no changes are made. This is a helpful wrapper around looping over all cells, and calling evaluateFormulaCell on each one.

evaluateAll

public void evaluateAll()

Loops over all cells in all sheets of the supplied workbook. For cells that contain formulas, their formulas are evaluated, and the results are saved. These cells remain as formula cells. For cells that do not contain formulas, no changes are made. This is a helpful wrapper around looping over all cells, and calling evaluateFormulaCell on each one.

Specified by:

evaluateAll in interface FormulaEvaluator

setIgnoreMissingWorkbooks

public void setIgnoreMissingWorkbooks(boolean ignore)

Whether to ignore missing references to external workbooks and use cached formula results in the main workbook instead.

In some cases exetrnal workbooks referenced by formulas in the main workbook are not avaiable. With this method you can control how POI handles such missing references:

• by default ignoreMissingWorkbooks=false and POI throws CollaboratingWorkbooksEnvironment.WorkbookNotFoundException if an external reference cannot be resolved
• if ignoreMissingWorkbooks=true then POI uses cached formula result that already exists in the main workbook

Parameters:

ignore - whether to ignore missing references to external workbooks