org.apache.poi.ss.usermodel.FormulaEvaluator Maven / Gradle / Ivy
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package org.apache.poi.ss.usermodel;
/**
* Evaluates formula cells.
*
* For performance reasons, this class keeps a cache of all previously calculated intermediate
* cell values. Be sure to call {@link #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 >
* @author Josh Micich
*/
public interface FormulaEvaluator {
/**
* Should be called whenever there are changes to input cells in the evaluated workbook.
* Failure to call this method after changing cell values will cause incorrect behaviour
* of the evaluate~ methods of this class
*/
void clearAllCachedResultValues();
/**
* 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
*/
void notifySetFormula(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(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
*/
void notifyUpdateCell(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.
* @param cell
*/
CellValue evaluate(Cell cell);
/**
* If cell contains formula, it evaluates the formula,
* and saves the result of the formula. The cell
* remains as a formula cell.
* Else if cell does not contain formula, this method leaves
* the cell unchanged.
* Note that the type of the formula result is returned,
* so you know what kind of value 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 {@link #evaluateInCell(Cell)}
* @param cell The cell to evaluate
* @return The type of the formula result (the cell's type remains as Cell.CELL_TYPE_FORMULA however)
*/
int evaluateFormulaCell(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 Cell 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 {@link #evaluateFormulaCell(Cell)}
* @param cell
*/
Cell evaluateInCell(Cell cell);
}