title: How to Get Excel Data Validations Drop Down values for Referenced Cell Ranges
body: <p>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.<a href="https://i.stack.imgur.com/pcSOB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/pcSOB.png" alt="enter image description here"></a></p>
  
  <p>I am able to get the values (720x486, etc) with the following by seeing if cell is within CellRangeAddress.:</p>
  
  <pre><code>    Map&lt;CellRangeAddress, String[]&gt; dropDownValues = new HashMap&lt;&gt;();
      List&lt;? extends DataValidation&gt; 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);
          }
      }
  </code></pre>
  
  <p>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:</p>
  
  <p><a href="https://i.stack.imgur.com/MUEDr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MUEDr.png" alt="enter image description here"></a></p>
  
  <pre><code>sheet.getDataValidations();
  </code></pre>
  
  <p>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? </p>