poi/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java

/* ====================================================================
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   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
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       http://www.apache.org/licenses/LICENSE-2.0

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   distributed under the License is distributed on an "AS IS" BASIS,
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   See the License for the specific language governing permissions and
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package org.apache.poi.hssf.usermodel;

import java.util.Iterator;

import org.apache.poi.hssf.record.formula.eval.BoolEval;
import org.apache.poi.hssf.record.formula.eval.ErrorEval;
import org.apache.poi.hssf.record.formula.eval.NumberEval;
import org.apache.poi.hssf.record.formula.eval.StringEval;
import org.apache.poi.hssf.record.formula.eval.ValueEval;
import org.apache.poi.hssf.record.formula.udf.UDFFinder;
import org.apache.poi.ss.formula.CollaboratingWorkbooksEnvironment;
import org.apache.poi.ss.formula.IStabilityClassifier;
import org.apache.poi.ss.formula.WorkbookEvaluator;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellValue;
import org.apache.poi.ss.usermodel.FormulaEvaluator;
import org.apache.poi.ss.usermodel.Row;

/**
 * Evaluates formula cells.<p/>
 *
 * 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 &lt; amolweb at ya hoo dot com &gt;
 * @author Josh Micich
 */
public class HSSFFormulaEvaluator implements FormulaEvaluator  {

	private WorkbookEvaluator _bookEvaluator;

	/**
	 * @deprecated (Sep 2008) HSSFSheet parameter is ignored
	 */
	public HSSFFormulaEvaluator(HSSFSheet sheet, HSSFWorkbook workbook) {
		this(workbook);
		if (false) {
			sheet.toString(); // suppress unused parameter compiler warning
		}
	}
	public HSSFFormulaEvaluator(HSSFWorkbook workbook) {
		this(workbook, null);
	}
	/**
	 * @param stabilityClassifier used to optimise caching performance. Pass <code>null</code>
	 * for the (conservative) assumption that any cell may have its definition changed after
	 * evaluation begins.
	 */
	public HSSFFormulaEvaluator(HSSFWorkbook workbook, IStabilityClassifier stabilityClassifier) {
		this(workbook, stabilityClassifier, null);
	}

	/**
	 * @param udfFinder pass <code>null</code> for default (AnalysisToolPak only)
	 */
	private HSSFFormulaEvaluator(HSSFWorkbook workbook, IStabilityClassifier stabilityClassifier, UDFFinder udfFinder) {
		_bookEvaluator = new WorkbookEvaluator(HSSFEvaluationWorkbook.create(workbook), stabilityClassifier, udfFinder);
	}

	/**
	 * @param stabilityClassifier used to optimise caching performance. Pass <code>null</code>
	 * for the (conservative) assumption that any cell may have its definition changed after
	 * evaluation begins.
	 * @param udfFinder pass <code>null</code> for default (AnalysisToolPak only)
	 */
	public static HSSFFormulaEvaluator create(HSSFWorkbook workbook, IStabilityClassifier stabilityClassifier, UDFFinder udfFinder) {
		return new HSSFFormulaEvaluator(workbook, stabilityClassifier, udfFinder);
	}


	/**
	 * Coordinates several formula evaluators together so that formulas that involve external
	 * references can be evaluated.
	 * @param 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")
	 * @param evaluators all evaluators for the full set of workbooks required by the formulas.
	 */
	public static void setupEnvironment(String[] workbookNames, HSSFFormulaEvaluator[] evaluators) {
		WorkbookEvaluator[] wbEvals = new WorkbookEvaluator[evaluators.length];
		for (int i = 0; i < wbEvals.length; i++) {
			wbEvals[i] = evaluators[i]._bookEvaluator;
		}
		CollaboratingWorkbooksEnvironment.setup(workbookNames, wbEvals);
	}

	/**
	 * Does nothing
	 * @deprecated (Aug 2008) - not needed, since the current row can be derived from the cell
	 */
	public void setCurrentRow(HSSFRow row) {
		// do nothing
		if (false) {
			row.getClass(); // suppress unused parameter compiler warning
		}
	}

	/**
	 * 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
	 */
	public void clearAllCachedResultValues() {
		_bookEvaluator.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
	 */
	public void notifyUpdateCell(HSSFCell cell) {
		_bookEvaluator.notifyUpdateCell(new HSSFEvaluationCell(cell));
	}
    public void notifyUpdateCell(Cell cell) {
        _bookEvaluator.notifyUpdateCell(new HSSFEvaluationCell((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
	 */
	public void notifyDeleteCell(HSSFCell cell) {
		_bookEvaluator.notifyDeleteCell(new HSSFEvaluationCell(cell));
	}
	public void notifyDeleteCell(Cell cell) {
		_bookEvaluator.notifyDeleteCell(new HSSFEvaluationCell((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
	 */
	public void notifySetFormula(Cell cell) {
		_bookEvaluator.notifyUpdateCell(new HSSFEvaluationCell((HSSFCell)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 may be <code>null</code> signifying that the cell is not present (or blank)
	 * @return <code>null</code> if the supplied cell is <code>null</code> or blank
	 */
	public CellValue evaluate(Cell cell) {
		if (cell == null) {
			return null;
		}

		switch (cell.getCellType()) {
			case HSSFCell.CELL_TYPE_BOOLEAN:
				return CellValue.valueOf(cell.getBooleanCellValue());
			case HSSFCell.CELL_TYPE_ERROR:
				return CellValue.getError(cell.getErrorCellValue());
			case HSSFCell.CELL_TYPE_FORMULA:
				return evaluateFormulaCellValue(cell);
			case HSSFCell.CELL_TYPE_NUMERIC:
				return new CellValue(cell.getNumericCellValue());
			case HSSFCell.CELL_TYPE_STRING:
				return new CellValue(cell.getRichStringCellValue().getString());
			case HSSFCell.CELL_TYPE_BLANK:
				return null;
		}
		throw new IllegalStateException("Bad cell type (" + cell.getCellType() + ")");
	}


	/**
	 * 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 <em>formula result</em> is returned, so you know what kind of
	 * cached formula result is also stored with  the formula.
	 * <pre>
	 * int evaluatedCellType = evaluator.evaluateFormulaCell(cell);
	 * </pre>
	 * 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(org.apache.poi.ss.usermodel.Cell)}
	 * @param cell The cell to evaluate
	 * @return -1 for non-formula cells, or the type of the <em>formula result</em>
	 */
	public int evaluateFormulaCell(Cell cell) {
		if (cell == null || cell.getCellType() != HSSFCell.CELL_TYPE_FORMULA) {
			return -1;
		}
		CellValue cv = evaluateFormulaCellValue(cell);
		// cell remains a formula cell, but the cached value is changed
		setCellValue(cell, cv);
		return cv.getCellType();
	}

	/**
	 * 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:
	 * <pre>
	 * int evaluatedCellType = evaluator.evaluateInCell(cell).getCellType();
	 * </pre>
	 * 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)}}
	 */
	public HSSFCell evaluateInCell(Cell cell) {
		if (cell == null) {
			return null;
		}
		HSSFCell result = (HSSFCell) cell;
		if (cell.getCellType() == HSSFCell.CELL_TYPE_FORMULA) {
			CellValue cv = evaluateFormulaCellValue(cell);
			setCellValue(cell, cv);
			setCellType(cell, cv); // cell will no longer be a formula cell
		}
		return result;
	}
	private static void setCellType(Cell cell, CellValue cv) {
		int cellType = cv.getCellType();
		switch (cellType) {
			case HSSFCell.CELL_TYPE_BOOLEAN:
			case HSSFCell.CELL_TYPE_ERROR:
			case HSSFCell.CELL_TYPE_NUMERIC:
			case HSSFCell.CELL_TYPE_STRING:
				cell.setCellType(cellType);
				return;
			case HSSFCell.CELL_TYPE_BLANK:
				// never happens - blanks eventually get translated to zero
			case HSSFCell.CELL_TYPE_FORMULA:
				// this will never happen, we have already evaluated the formula
		}
		throw new IllegalStateException("Unexpected cell value type (" + cellType + ")");
	}

	private static void setCellValue(Cell cell, CellValue cv) {
		int cellType = cv.getCellType();
		switch (cellType) {
			case HSSFCell.CELL_TYPE_BOOLEAN:
				cell.setCellValue(cv.getBooleanValue());
				break;
			case HSSFCell.CELL_TYPE_ERROR:
				cell.setCellErrorValue(cv.getErrorValue());
				break;
			case HSSFCell.CELL_TYPE_NUMERIC:
				cell.setCellValue(cv.getNumberValue());
				break;
			case HSSFCell.CELL_TYPE_STRING:
				cell.setCellValue(new HSSFRichTextString(cv.getStringValue()));
				break;
			case HSSFCell.CELL_TYPE_BLANK:
				// never happens - blanks eventually get translated to zero
			case HSSFCell.CELL_TYPE_FORMULA:
				// this will never happen, we have already evaluated the formula
			default:
				throw new IllegalStateException("Unexpected cell value type (" + cellType + ")");
		}
	}

	/**
	 * 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.
	 */
	public static void evaluateAllFormulaCells(HSSFWorkbook wb) {
		HSSFFormulaEvaluator evaluator = new HSSFFormulaEvaluator(wb);
		for(int i=0; i<wb.getNumberOfSheets(); i++) {
			HSSFSheet sheet = wb.getSheetAt(i);

			for (Iterator<Row> rit = sheet.rowIterator(); rit.hasNext();) {
				Row r = rit.next();

				for (Iterator<Cell> cit = r.cellIterator(); cit.hasNext();) {
					Cell c = cit.next();
					if (c.getCellType() == HSSFCell.CELL_TYPE_FORMULA)
						evaluator.evaluateFormulaCell(c);
				}
			}
		}
	}

	/**
	 * Returns a CellValue wrapper around the supplied ValueEval instance.
	 * @param eval
	 */
	private CellValue evaluateFormulaCellValue(Cell cell) {
		ValueEval eval = _bookEvaluator.evaluate(new HSSFEvaluationCell((HSSFCell)cell));
		if (eval instanceof NumberEval) {
			NumberEval ne = (NumberEval) eval;
			return new CellValue(ne.getNumberValue());
		}
		if (eval instanceof BoolEval) {
			BoolEval be = (BoolEval) eval;
			return CellValue.valueOf(be.getBooleanValue());
		}
		if (eval instanceof StringEval) {
			StringEval ne = (StringEval) eval;
			return new CellValue(ne.getStringValue());
		}
		if (eval instanceof ErrorEval) {
			return CellValue.getError(((ErrorEval)eval).getErrorCode());
		}
		throw new RuntimeException("Unexpected eval class (" + eval.getClass().getName() + ")");
	}
}