Apache POI add new column to pivot table - apache-poi

Question

I have a pivot table which has column labels "Total sales" and "Individual Sales". I want to add a new column to the pivot table to calculate the percentage of sales (Individual sales / Total sales *100). I am having problem adding this new calculated column to pivot table.
I think my problem is with the following line of code.
ctCacheField.setFormula("'Individual Sales'/'Total Sales' * 100") in
addFormulaToCache method.
Note: Individual Sales and Total Sales in the above line is the column names i have in pivot table.
Here is my complete code. When i run this code, it generates the Excel. But when i open the Excel, i get an error and i don't see the Pivot table.
AreaReference a=new AreaReference("Data!A1:C6");
/* Define the starting Cell Reference for the Pivot Table */
CellReference b=new CellReference("A1");
/* Create the Pivot Table */
XSSFPivotTable pivotTable = sheet1.createPivotTable(a,b);
pivotTable.addRowLabel(0);
// 1. Add Formula to cache
addFormulaToCache(pivotTable);
// 2. Add PivotField for Formula column
addPivotFieldForNewColumn(pivotTable);
// 3. Add all column labels before our function..
pivotTable.addColumnLabel(DataConsolidateFunction.COUNT, 2, "Total Sales");
pivotTable.addColumnLabel(DataConsolidateFunction.SUM, 1, "Individual Sales");
addFormulaColumn(pivotTable);
/* Write output to file */
FileOutputStream output_file = new FileOutputStream(new File("C:\\POI_XLS_Pivot_Example.xlsx")); //create XLSX file
new_workbook.write(output_file);//write excel document to output stream
output_file.close(); //close the file
}
private static void addFormulaToCache(XSSFPivotTable pivotTable) {
CTCacheFields ctCacheFields = pivotTable.getPivotCacheDefinition().getCTPivotCacheDefinition().getCacheFields();
CTCacheField ctCacheField = ctCacheFields.addNewCacheField();
ctCacheField.setName("Field1"); // Any field name
**ctCacheField.setFormula("'Individual Sales'/'Total Sales' * 100");** //This is where the problem could be
ctCacheField.setDatabaseField(false);
ctCacheField.setNumFmtId(0);
ctCacheFields.setCount(ctCacheFields.sizeOfCacheFieldArray()); //!!! update count of fields directly
}
private static void addPivotFieldForNewColumn(XSSFPivotTable pivotTable) {
CTPivotField pivotField = pivotTable.getCTPivotTableDefinition().getPivotFields().addNewPivotField();
pivotField.setDataField(true);
pivotField.setDragToCol(false);
pivotField.setDragToPage(false);
pivotField.setDragToRow(false);
pivotField.setShowAll(false);
pivotField.setDefaultSubtotal(false);
}
private static void addFormulaColumn(XSSFPivotTable pivotTable) {
CTDataFields dataFields;
if(pivotTable.getCTPivotTableDefinition().getDataFields() != null) {
dataFields = pivotTable.getCTPivotTableDefinition().getDataFields();
} else {
// can be null if we have not added any column labels yet
dataFields = pivotTable.getCTPivotTableDefinition().addNewDataFields();
}
CTDataField dataField = dataFields.addNewDataField();
dataField.setName("%age Group Difference");
// set index of cached field with formula - it is the last one!!!
dataField.setFld(pivotTable.getPivotCacheDefinition().getCTPivotCacheDefinition().getCacheFields().getCount()-1);
dataField.setBaseItem(0);
dataField.setBaseField(0);
}

Answer 1

This question is a follow-on from another question: XSSF (POI) - Adding “formula” column to pivot table
The missing piece to your question is that "Individual Sales" and "Total Sales" are made-up column names in your pivot table. Assuming your source is:
Fruit | Price
Apple | 1.5
Orange | 1
Your formula to get Price * 2 would naturally be "'Price' * 2" irregardless of the name in the pivot table. If you truly wish to reference the made-up name, your formula becomes more complicated. For your pivot table in cell A1, a reference to "Individual Sales" would be:
GETPIVOTDATA("Individual Sales",$A$1,<Filter Name>,<Filter Value>)
But this defeats the purpose of a pivot table.
As an additional note, should you desire, all three pieces of valerii ryzhuk's answer can be put into a single function. They don't need to be split-up except to explain the answer.