I have stumbled upon a problem when reading in an Excel document, specifically acquiring drop down values (Data Validation) from a Cells. I am able to get the values defined explicitly.
I am able to get the values (720×486, etc) with the following by seeing if cell is within CellRangeAddress.:
Map<CellRangeAddress, String[]> dropDownValues = new HashMap<>();
List<? extends DataValidation> dataValidations = sheet.getDataValidations();
for(DataValidation dataValidation : dataValidations)
{
for(CellRangeAddress cellRangeAddress : dataValidation.getRegions().getCellRangeAddresses())
{
String[] explicitListValues = dataValidation.getValidationConstraint().getExplicitListValues();
if(explicitListValues == null)
{
continue;
}
dropDownValues.put(cellRangeAddress, explicitListValues);
}
}
The code above works only for explicit values. The problem I see is when a range is defined in the source of the Data Validation for a cell:
sheet.getDataValidations();
Does not return anything in regards to the range or any info on the Data Validations. Has anyone been able to get a hold of the Source and evaluate the formula to attain values?
I was able to retrieve the data validations defined by a formula for Excel Sheets newer than 2003.
I had to parse the XSSFSheet for the specific info and then reconstruct and evaluate formula.
Here is what I did to attain all DataValidation values:
Map<CellRangeAddress, String[]> dropDownValues = new HashMap<>();
List<ExtendedDataValidations> extendedDataValidationsList = getExtendedDataValidations(sheet);
for (ExtendedDataValidations extendedDataValidations : extendedDataValidationsList)
{
AreaReference formulaReference = new AreaReference(extendedDataValidations.formula);
CellReference[] allReferencedCells = formulaReference.getAllReferencedCells();
FormulaEvaluator formulaEvaluator = wb.getCreationHelper().createFormulaEvaluator();
String[] values = new String[allReferencedCells.length];
for (int j = 0; j < allReferencedCells.length; j++)
{
CellReference cellReference = allReferencedCells[j];
Sheet valueSheet = wb.getSheet(cellReference.getSheetName());
Cell cell = valueSheet.getRow(cellReference.getRow()).getCell(cellReference.getCol());
CellValue evaluate = formulaEvaluator.evaluate(cell);
values[j] = StringUtils.trimToEmpty(StringUtils.removeStart(StringUtils.removeEnd(evaluate.formatAsString(), "\""), "\""));
}
String stRef = extendedDataValidations.sqref;
String[] regions = stRef.split(" ");
for (String region : regions)
{
String[] parts = region.split(":");
CellReference begin = new CellReference(parts[0]);
CellReference end = parts.length > 1 ? new CellReference(parts[1]) : begin;
CellRangeAddress cellRangeAddress = new CellRangeAddress(begin.getRow(), end.getRow(), begin.getCol(), end.getCol());
dropDownValues.put(cellRangeAddress, values);
}
}
In addition I defined a Struc for the formula and cell reference.
private static class ExtendedDataValidations
{
public String formula;
public String sqref;
}
getExtendedDataValidations grabbed the CTExtensionList where the data validation forumla appeared in the sheet:
public static List<ExtendedDataValidations> getExtendedDataValidations(Sheet sheet)
{
List<ExtendedDataValidations> extendedDataValidationsList = new ArrayList<>();
if (sheet instanceof XSSFSheet)
{
CTExtensionList extLst = ((XSSFSheet) sheet).getCTWorksheet().getExtLst();
if (extLst == null)
{
return extendedDataValidationsList;
}
CTExtension[] extArray = extLst.getExtArray();
List<Node> dataValidationNodes = new ArrayList<>();
for (CTExtension anExtArray : extArray)
{
searchForDataValidation(anExtArray.getDomNode(), dataValidationNodes);
}
for (Node dataValidationNode : dataValidationNodes)
{
ExtendedDataValidations dataValidations = new ExtendedDataValidations();
getDataValidationInfo(dataValidationNode, dataValidations);
extendedDataValidationsList.add(dataValidations);
}
}
return extendedDataValidationsList;
}
searchForDataValidation had to traverse the DOM nodes of the sheet looking for specific info on DataValidation. If found Save it in List:
private static void searchForDataValidation(Node node, List<Node> nodesInQuestion)
{
if (StringUtils.equalsIgnoreCase("x14:dataValidation", node.getNodeName()))
{
nodesInQuestion.add(node);
return;
}
for (int i = 0; i < node.getChildNodes().getLength(); i++)
{
searchForDataValidation(node.getChildNodes().item(i), nodesInQuestion);
}
}
getDataValidationInfo was in charge of getting the formula and Cell Reference.
private static void getDataValidationInfo(Node node, ExtendedDataValidations dataValidations)
{
if (StringUtils.equalsIgnoreCase("#text", node.getNodeName()))
{
if (StringUtils.equalsIgnoreCase("xm:sqref", node.getParentNode().getNodeName()))
{
dataValidations.sqref = node.getNodeValue();
}
else if (StringUtils.equalsIgnoreCase("xm:f", node.getParentNode().getNodeName()))
{
dataValidations.formula = node.getNodeValue();
}
return;
}
for (int i = 0; i < node.getChildNodes().getLength(); i++)
{
getDataValidationInfo(node.getChildNodes().item(i), dataValidations);
}
}
Might appear to be complicated, but it does the trick. Hope it helps!
Tags: excel, javajava, validation
