feat: add support for providing excel formats per cell

Closes #93

Author: mlopezFC

src/main/java/com/flowingcode/vaadin/addons/gridexporter/ExcelInputStreamFactory.java

@@ -30,7 +30,9 @@
 import java.time.LocalDate;
 import java.time.ZoneId;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.apache.commons.lang3.ArrayUtils;
@@ -57,6 +59,7 @@
 import com.vaadin.flow.data.binder.BeanPropertySet;
 import com.vaadin.flow.data.binder.PropertySet;
 import com.vaadin.flow.data.provider.DataProvider;
+import com.vaadin.flow.function.ValueProvider;
 
 /**
  * @author mlopez
@@ -66,6 +69,7 @@ class ExcelInputStreamFactory<T> extends BaseInputStreamFactory<T> {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(ExcelInputStreamFactory.class);
   private static final String DEFAULT_TEMPLATE = "/template.xlsx";
+  private static final String COLUMN_CELLSTYLE_MAP = "colum-cellstyle-map";
 
   public ExcelInputStreamFactory(GridExporter<T> exporter, String template) {
     super(exporter, template, DEFAULT_TEMPLATE);
@@ -279,7 +283,7 @@ private void buildRow(T item, Sheet sheet, Cell startingCell) {
                 configureAlignment(column.getTextAlign(), currentCell);
               }
               currentColumn[0] = currentColumn[0] + 1;
-              buildCell(value, currentCell, column);
+              buildCell(value, currentCell, column, item);
             });
   }
 
@@ -331,31 +335,52 @@ protected void configureAlignment(ColumnTextAlign columnTextAlign, Cell currentC
     }
   }
 
-  private void buildCell(Object value, Cell cell, Column<T> column) {
-    String excelFormat =
-        (String) ComponentUtil.getData(column, GridExporter.COLUMN_EXCEL_FORMAT_DATA);
+  @SuppressWarnings("unchecked")
+  private void buildCell(Object value, Cell cell, Column<T> column, T item) {
+    ValueProvider<T,String> provider = null;
+    provider = (ValueProvider<T, String>) ComponentUtil.getData(column, GridExporter.COLUMN_EXCEL_FORMAT_DATA_PROVIDER);
+    String excelFormat;
+    Map<String,CellStyle> cellStyles = (Map<String, CellStyle>) ComponentUtil.getData(column, COLUMN_CELLSTYLE_MAP);
+    if (cellStyles==null) {
+      cellStyles = new HashMap<>();
+      ComponentUtil.setData(column, COLUMN_CELLSTYLE_MAP, cellStyles);
+    }
+    if (provider!=null) {
+      excelFormat = provider.apply(item);
+    } else {
+      excelFormat =
+          (String) ComponentUtil.getData(column, GridExporter.COLUMN_EXCEL_FORMAT_DATA);
+    }
     if (value == null) {
       PoiHelper.setBlank(cell);
     } else if (value instanceof Number) {
       excelFormat = (excelFormat!=null)?excelFormat:"0";
-      applyExcelFormat(cell, excelFormat);
       cell.setCellValue(((Number) value).doubleValue());
+      applyExcelFormat(cell, excelFormat, cellStyles);
     } else if (value instanceof Date) {
       excelFormat = (excelFormat!=null)?excelFormat:"dd/MM/yyyy";
-      applyExcelFormat(cell, excelFormat);
+      applyExcelFormat(cell, excelFormat, cellStyles);
       cell.setCellValue((Date) value);
     } else if (value instanceof LocalDate) {
       excelFormat = (excelFormat!=null)?excelFormat:"dd/MM/yyyy";
-      applyExcelFormat(cell, excelFormat);
+      applyExcelFormat(cell, excelFormat, cellStyles);
       cell.setCellValue(
           Date.from(((LocalDate) value).atStartOfDay(ZoneId.systemDefault()).toInstant()));
     } else {
       cell.setCellValue(value.toString());
     }
   }
 
-  private void applyExcelFormat(Cell cell, String excelFormat) {
+  private void applyExcelFormat(Cell cell, String excelFormat, Map<String, CellStyle> cellStyles) {
     DataFormat format = cell.getSheet().getWorkbook().createDataFormat();
+    if (excelFormat!=null && cellStyles.get(excelFormat)==null) {
+      CellStyle cs = cell.getSheet().getWorkbook().createCellStyle();
+      cs.cloneStyleFrom(cell.getCellStyle());
+      cellStyles.put(excelFormat, cs);
+      cell.setCellStyle(cs);
+    } else if (excelFormat!=null) {
+      cell.setCellStyle(cellStyles.get(excelFormat));
+    }
     cell.getCellStyle().setDataFormat(format.getFormat(excelFormat));
   }
 
@@ -406,7 +431,7 @@ private void fillHeaderOrFooter(
               (isHeader
                   ? headerOrFooter.getLeft()
                   : transformToType(headerOrFooter.getLeft(), headerOrFooter.getRight()));
-          buildCell(value, cell, headerOrFooter.getRight());
+          buildCell(value, cell, headerOrFooter.getRight(), null);
           configureAlignment(headerOrFooter.getRight().getTextAlign(), cell);
           sheet.setActiveCell(
               new CellAddress(

src/main/java/com/flowingcode/vaadin/addons/gridexporter/GridExporter.java

@@ -66,6 +66,7 @@ public class GridExporter<T> implements Serializable {
   static final String COLUMN_EXPORTED_PROVIDER_DATA = "column-value-exported-data";
   static final String COLUMN_PARSING_FORMAT_PATTERN_DATA = "column-parsing-format-pattern-data";
   static final String COLUMN_EXCEL_FORMAT_DATA = "column-excel-format-data";
+  static final String COLUMN_EXCEL_FORMAT_DATA_PROVIDER = "column-excel-format-data-provider";
   static final String COLUMN_TYPE_DATA = "column-type-data";
   static final String COLUMN_TYPE_NUMBER = "number";
   static final String COLUMN_TYPE_DATE = "date";
@@ -452,6 +453,23 @@ public void setNumberColumnFormat(
     ComponentUtil.setData(column, COLUMN_TYPE_DATA, COLUMN_TYPE_NUMBER);
   }
 
+  /**
+   * If the column is based on a String, it configures a DecimalFormat to parse a number from the
+   * value of the column so it can be converted to a Double, and then allows to specify the excel
+   * format to be applied to the cell when exported to excel with a provider, so the resulting cell
+   * is not a string but a number that can be used in formulas.
+   * 
+   * @param column
+   * @param decimalFormat
+   * @param excelFormatProvider
+   */
+  public void setNumberColumnFormatProvider(Column<T> column, DecimalFormat decimalFormat,
+      ValueProvider<T, String> excelFormatProvider) {
+    ComponentUtil.setData(column, COLUMN_PARSING_FORMAT_PATTERN_DATA, decimalFormat);
+    ComponentUtil.setData(column, COLUMN_EXCEL_FORMAT_DATA_PROVIDER, excelFormatProvider);
+    ComponentUtil.setData(column, COLUMN_TYPE_DATA, COLUMN_TYPE_NUMBER);
+  }
+
   /**
    * If the column is based on a String, it configures a DateFormat to parse a date from the value
    * of the column so it can be converted to a java.util.Date, and then allows to specify the excel
@@ -468,6 +486,23 @@ public void setDateColumnFormat(Column<T> column, DateFormat dateFormat, String
     ComponentUtil.setData(column, COLUMN_TYPE_DATA, COLUMN_TYPE_DATE);
   }
 
+  /**
+   * If the column is based on a String, it configures a DateFormat to parse a date from the value
+   * of the column so it can be converted to a java.util.Date, and then allows to specify the excel
+   * format to be applied to the cell when exported to excel, so the resulting cell is not a string
+   * but a date that can be used in formulas.
+   *
+   * @param column
+   * @param dateFormat
+   * @param excelFormat
+   */
+  public void setDateColumnFormatProvider(Column<T> column, DateFormat dateFormat,
+      ValueProvider<T, String> excelFormatProvider) {
+    ComponentUtil.setData(column, COLUMN_PARSING_FORMAT_PATTERN_DATA, dateFormat);
+    ComponentUtil.setData(column, COLUMN_EXCEL_FORMAT_DATA_PROVIDER, excelFormatProvider);
+    ComponentUtil.setData(column, COLUMN_TYPE_DATA, COLUMN_TYPE_DATE);
+  }
+
   /**
    * If the column is based on a number attribute of the item, rendered with a NumberRenderer, it
    * configures the excel format to be applied to the cell when exported to excel, so the resulting

src/test/java/com/flowingcode/vaadin/addons/gridexporter/GridExporterSimpleCustomTemplateDemo.java

@@ -41,6 +41,7 @@
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Calendar;
+import java.util.Random;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.IntStream;
 import java.util.stream.Stream;
@@ -69,6 +70,10 @@ public GridExporterSimpleCustomTemplateDemo() throws EncryptedDocumentException,
         grid.addColumn(item -> decimalFormat.format(item.getBudget() + (item.getBudget() / 2)))
             .setHeader("Max. Budget")
             .setTextAlign(ColumnTextAlign.END);
+    Column<Person> quantityColumn =
+        grid.addColumn(item -> decimalFormat.format(item.getBudget() + (new Random().nextInt(10))))
+            .setHeader("Quantity")
+            .setTextAlign(ColumnTextAlign.END);
     Column<Person> dateColumn1 =
         grid.addColumn(new LocalDateRenderer<>(Person::getFavDate, "dd/MM/yyyy"))
             .setHeader("Fav Date")
@@ -104,6 +109,7 @@ public GridExporterSimpleCustomTemplateDemo() throws EncryptedDocumentException,
     exporter.setCsvExportEnabled(false);
     exporter.setNumberColumnFormat(minBudgetColumn, "$#.###,##");
     exporter.setNumberColumnFormat(maxBudgetColumn, decimalFormat, "$#,###.##");
+    exporter.setNumberColumnFormatProvider(quantityColumn, decimalFormat, (person)->person.getBudget()>50000?"#,###.## \"kg\"":"#,###.## \"l\"");
     exporter.setDateColumnFormat(dateColumn1, "dd/MM/yyyy");
     exporter.setDateColumnFormat(dateColumn2, new SimpleDateFormat("dd/MM/yyyy"), "dd/MM/yyyy");
     exporter.setFileName(