Allow merging header and footer cells again #13334

This changeset adds the possibility to merge header and footer cells by
using HeaderRow.join().

Note: Currently this does not support hidden columns, support for it
should be added in a later changeset.

Change-Id: I42e089ef2ac6eea304e355423b274159a79baa89

8 files changed, 323 insertions, 18 deletions

diff --git a/client/src/com/vaadin/client/ui/grid/Grid.java b/client/src/com/vaadin/client/ui/grid/Grid.java
index ff75417c12..1e310e3ec4 100644
--- a/client/src/com/vaadin/client/ui/grid/Grid.java
+++ b/client/src/com/vaadin/client/ui/grid/Grid.java
@@ -46,6 +46,7 @@ import com.vaadin.client.data.DataChangeHandler;
 import com.vaadin.client.data.DataSource;
 import com.vaadin.client.ui.SubPartAware;
 import com.vaadin.client.ui.grid.GridHeader.HeaderRow;
+import com.vaadin.client.ui.grid.GridStaticSection.StaticCell;
 import com.vaadin.client.ui.grid.renderers.ComplexRenderer;
 import com.vaadin.client.ui.grid.renderers.TextRenderer;
 import com.vaadin.client.ui.grid.renderers.WidgetRenderer;
@@ -1436,9 +1437,15 @@ public class Grid<T> extends Composite implements
             final List<Integer> columnIndices = getVisibleColumnIndices();
 
             for (FlyweightCell cell : cellsToUpdate) {
+
                 int index = columnIndices.get(cell.getColumn());
-                gridRow.getRenderer().render(cell,
-                        gridRow.getCell(index).getText());
+                StaticCell metadata = gridRow.getCell(index);
+
+                // Assign colspan to cell before rendering
+                cell.setColSpan(metadata.getColspan());
+
+                // Render
+                gridRow.getRenderer().render(cell, metadata.getText());
 
                 activeCellHandler.updateActiveCellStyle(cell, container);
             }
diff --git a/client/src/com/vaadin/client/ui/grid/GridConnector.java b/client/src/com/vaadin/client/ui/grid/GridConnector.java
index 3c7629a60d..458dc7e1d2 100644
--- a/client/src/com/vaadin/client/ui/grid/GridConnector.java
+++ b/client/src/com/vaadin/client/ui/grid/GridConnector.java
@@ -377,7 +377,7 @@ public class GridConnector extends AbstractComponentConnector {
 
         section.setVisible(state.visible);
 
-        section.refreshGrid();
+        section.refreshSection();
     }
 
     /**
diff --git a/client/src/com/vaadin/client/ui/grid/GridFooter.java b/client/src/com/vaadin/client/ui/grid/GridFooter.java
index 7f478f7d29..eba6ad81cb 100644
--- a/client/src/com/vaadin/client/ui/grid/GridFooter.java
+++ b/client/src/com/vaadin/client/ui/grid/GridFooter.java
@@ -56,7 +56,7 @@ public class GridFooter extends GridStaticSection<GridFooter.FooterRow> {
     }
 
     @Override
-    protected void refreshGrid() {
+    protected void refreshSection() {
         getGrid().refreshFooter();
     }
 }
diff --git a/client/src/com/vaadin/client/ui/grid/GridHeader.java b/client/src/com/vaadin/client/ui/grid/GridHeader.java
index c5b0febeca..4e046873f4 100644
--- a/client/src/com/vaadin/client/ui/grid/GridHeader.java
+++ b/client/src/com/vaadin/client/ui/grid/GridHeader.java
@@ -24,7 +24,7 @@ import com.vaadin.client.ui.grid.Grid.AbstractGridColumn.SortableColumnHeaderRen
  * 
  * TODO Arbitrary number of header rows (zero included, one by default)
  * 
- * TODO Merging header cells
+ * TODO Account for hidden columns when merging header cells
  * 
  * TODO "Default" row with sorting
  * 
@@ -114,7 +114,7 @@ public class GridHeader extends GridStaticSection<GridHeader.HeaderRow> {
             row.setDefault(true);
         }
         defaultRow = row;
-        refreshGrid();
+        refreshSection();
     }
 
     /**
@@ -133,7 +133,7 @@ public class GridHeader extends GridStaticSection<GridHeader.HeaderRow> {
     }
 
     @Override
-    protected void refreshGrid() {
+    protected void refreshSection() {
         getGrid().refreshHeader();
     }
 }
diff --git a/client/src/com/vaadin/client/ui/grid/GridStaticSection.java b/client/src/com/vaadin/client/ui/grid/GridStaticSection.java
index 4318811ca2..fa4f3e5ea0 100644
--- a/client/src/com/vaadin/client/ui/grid/GridStaticSection.java
+++ b/client/src/com/vaadin/client/ui/grid/GridStaticSection.java
@@ -16,6 +16,9 @@
 package com.vaadin.client.ui.grid;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
 
 import com.vaadin.client.ui.grid.renderers.TextRenderer;
@@ -41,17 +44,19 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
 
         private String text = "";
 
+        private int colspan = 1;
+
         private GridStaticSection<?> section;
 
         /**
          * Sets the text displayed in this cell.
-         *
+         * 
          * @param text
          *            a plain text caption
          */
         public void setText(String text) {
             this.text = text;
-            section.refreshGrid();
+            section.refreshSection();
         }
 
         /**
@@ -72,6 +77,21 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
             this.section = section;
         }
 
+        /**
+         * @return the colspan
+         */
+        public int getColspan() {
+            return colspan;
+        }
+
+        /**
+         * @param colspan
+         *            the colspan to set
+         */
+        public void setColspan(int colspan) {
+            this.colspan = colspan;
+        }
+
     }
 
     /**
@@ -88,6 +108,8 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
 
         private GridStaticSection<?> section;
 
+        private Collection<List<CELLTYPE>> cellGroups = new HashSet<List<CELLTYPE>>();
+
         /**
          * Returns the cell at the given position in this row.
          * 
@@ -101,6 +123,105 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
             return cells.get(index);
         }
 
+        /**
+         * Merges cells in a row
+         * 
+         * @param cells
+         *            The cells to be merged
+         * @return The first cell of the merged cells
+         */
+        protected CELLTYPE join(List<CELLTYPE> cells) {
+            assert cells.size() > 1 : "You cannot merge less than 2 cells together";
+
+            // Ensure no cell is already grouped
+            for (CELLTYPE cell : cells) {
+                if (getCellGroupForCell(cell) != null) {
+                    throw new IllegalStateException("Cell " + cell.getText()
+                            + " is already grouped.");
+                }
+            }
+
+            // Ensure continuous range
+            int firstCellIndex = this.cells.indexOf(cells.get(0));
+            for (int i = 0; i < cells.size(); i++) {
+                if (this.cells.get(firstCellIndex + i) != cells.get(i)) {
+                    throw new IllegalStateException(
+                            "Cell range must be a continous range");
+                }
+            }
+
+            // Create a new group
+            cellGroups.add(new ArrayList<CELLTYPE>(cells));
+
+            calculateColspans();
+
+            getSection().refreshSection();
+
+            // Returns first cell of group
+            return cells.get(0);
+        }
+
+        /**
+         * Merges columns cells in a row
+         * 
+         * @param columns
+         *            The columns which header should be merged
+         * @return The remaining visible cell after the merge
+         */
+        public CELLTYPE join(GridColumn<?, ?>... columns) {
+            assert columns.length > 1 : "You cannot merge less than 2 columns together";
+
+            // Convert columns to cells
+            List<CELLTYPE> cells = new ArrayList<CELLTYPE>();
+            for (GridColumn<?, ?> c : columns) {
+                int index = getSection().getGrid().getColumns().indexOf(c);
+                cells.add(this.cells.get(index));
+            }
+
+            return join(cells);
+        }
+
+        /**
+         * Merges columns cells in a row
+         * 
+         * @param cells
+         *            The cells to merge. Must be from the same row.
+         * @return The remaining visible cell after the merge
+         */
+        public CELLTYPE join(CELLTYPE... cells) {
+            return join(Arrays.asList(cells));
+        }
+
+        private List<CELLTYPE> getCellGroupForCell(CELLTYPE cell) {
+            for (List<CELLTYPE> group : cellGroups) {
+                if (group.contains(cell)) {
+                    return group;
+                }
+            }
+            return null;
+        }
+
+        private void calculateColspans() {
+            // Reset all cells
+            for (CELLTYPE cell : cells) {
+                cell.setColspan(1);
+            }
+
+            // Set colspan for grouped cells
+            for (List<CELLTYPE> group : cellGroups) {
+                for (int i = 0; i < group.size(); i++) {
+                    CELLTYPE cell = group.get(i);
+                    if (i == 0) {
+                        // Assign full colspan to first cell
+                        cell.setColspan(group.size());
+                    } else {
+                        // Hide other cells
+                        cell.setColspan(0);
+                    }
+                }
+            }
+        }
+
         protected void addCell(int index) {
             CELLTYPE cell = createCell();
             cell.setSection(getSection());
@@ -146,7 +267,7 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
     /**
      * Informs the grid that this section should be re-rendered.
      */
-    protected abstract void refreshGrid();
+    protected abstract void refreshSection();
 
     /**
      * Sets the visibility of the whole section.
@@ -156,7 +277,7 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
      */
     public void setVisible(boolean visible) {
         this.visible = visible;
-        refreshGrid();
+        refreshSection();
     }
 
     /**
@@ -185,7 +306,7 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
             row.addCell(i);
         }
         rows.add(index, row);
-        refreshGrid();
+        refreshSection();
         return row;
     }
 
@@ -218,12 +339,12 @@ abstract class GridStaticSection<ROWTYPE extends GridStaticSection.StaticRow<?>>
      */
     public void removeRow(int index) {
         rows.remove(index);
-        refreshGrid();
+        refreshSection();
     }
 
     /**
      * Removes the given row from the section.
-     *
+     * 
      * @param row
      *            the row to be removed
      * 
diff --git a/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridFooterTest.java b/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridFooterTest.java
index f7dd85e3c3..e117ed5fbb 100644
--- a/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridFooterTest.java
+++ b/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridFooterTest.java
@@ -16,9 +16,13 @@
 package com.vaadin.tests.components.grid.basicfeatures;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 import org.junit.Test;
 
+import com.vaadin.tests.components.grid.GridElement.GridCellElement;
+
 public class GridFooterTest extends GridStaticSectionTest {
 
     @Test
@@ -85,6 +89,57 @@ public class GridFooterTest extends GridStaticSectionTest {
         assertFooterCount(0);
     }
 
+    @Test
+    public void joinColumnsByCells() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Footer", "Append row");
+
+        selectMenuPath("Component", "Footer", "Row 1", "Join column cells 0, 1");
+
+        GridCellElement spannedCell = getGridElement().getFooterCell(0, 0);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("2", spannedCell.getAttribute("colspan"));
+
+        GridCellElement hiddenCell = getGridElement().getFooterCell(0, 1);
+        assertFalse(hiddenCell.isDisplayed());
+    }
+
+    @Test
+    public void joinColumnsByColumns() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Footer", "Append row");
+
+        selectMenuPath("Component", "Footer", "Row 1", "Join columns 1, 2");
+
+        GridCellElement spannedCell = getGridElement().getFooterCell(0, 1);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("2", spannedCell.getAttribute("colspan"));
+
+        GridCellElement hiddenCell = getGridElement().getFooterCell(0, 2);
+        assertFalse(hiddenCell.isDisplayed());
+    }
+
+    @Test
+    public void joinAllColumnsInRow() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Footer", "Append row");
+
+        selectMenuPath("Component", "Footer", "Row 1", "Join all columns");
+
+        GridCellElement spannedCell = getGridElement().getFooterCell(0, 0);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("11", spannedCell.getAttribute("colspan"));
+
+        for (int columnIndex = 1; columnIndex < 11; columnIndex++) {
+            GridCellElement hiddenCell = getGridElement().getFooterCell(0,
+                    columnIndex);
+            assertFalse(hiddenCell.isDisplayed());
+        }
+    }
+
     private void assertFooterCount(int count) {
         assertEquals("footer count", count, getGridElement().getFooterCount());
     }
diff --git a/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridHeaderTest.java b/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridHeaderTest.java
index 1b27350f25..771c0da810 100644
--- a/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridHeaderTest.java
+++ b/uitest/src/com/vaadin/tests/components/grid/basicfeatures/GridHeaderTest.java
@@ -159,6 +159,57 @@ public class GridHeaderTest extends GridStaticSectionTest {
         assertFalse(hasClassName(headerCell, "sort-desc"));
     }
 
+    @Test
+    public void joinHeaderColumnsByCells() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Header", "Append row");
+
+        selectMenuPath("Component", "Header", "Row 2", "Join column cells 0, 1");
+
+        GridCellElement spannedCell = getGridElement().getHeaderCell(1, 0);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("2", spannedCell.getAttribute("colspan"));
+
+        GridCellElement hiddenCell = getGridElement().getHeaderCell(1, 1);
+        assertFalse(hiddenCell.isDisplayed());
+    }
+
+    @Test
+    public void joinHeaderColumnsByColumns() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Header", "Append row");
+
+        selectMenuPath("Component", "Header", "Row 2", "Join columns 1, 2");
+
+        GridCellElement spannedCell = getGridElement().getHeaderCell(1, 1);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("2", spannedCell.getAttribute("colspan"));
+
+        GridCellElement hiddenCell = getGridElement().getHeaderCell(1, 2);
+        assertFalse(hiddenCell.isDisplayed());
+    }
+
+    @Test
+    public void joinAllColumnsInHeaderRow() throws Exception {
+        openTestURL();
+
+        selectMenuPath("Component", "Header", "Append row");
+
+        selectMenuPath("Component", "Header", "Row 2", "Join all columns");
+
+        GridCellElement spannedCell = getGridElement().getHeaderCell(1, 0);
+        assertTrue(spannedCell.isDisplayed());
+        assertEquals("11", spannedCell.getAttribute("colspan"));
+
+        for (int columnIndex = 1; columnIndex < 11; columnIndex++) {
+            GridCellElement hiddenCell = getGridElement().getHeaderCell(1,
+                    columnIndex);
+            assertFalse(hiddenCell.isDisplayed());
+        }
+    }
+
     private void assertHeaderCount(int count) {
         assertEquals("header count", count, getGridElement().getHeaderCount());
     }
diff --git a/uitest/src/com/vaadin/tests/widgetset/client/grid/GridBasicClientFeatures.java b/uitest/src/com/vaadin/tests/widgetset/client/grid/GridBasicClientFeatures.java
index e013306dc0..b6dfdc8635 100644
--- a/uitest/src/com/vaadin/tests/widgetset/client/grid/GridBasicClientFeatures.java
+++ b/uitest/src/com/vaadin/tests/widgetset/client/grid/GridBasicClientFeatures.java
@@ -311,13 +311,13 @@ public class GridBasicClientFeatures extends
         addMenuCommand("Prepend row", new ScheduledCommand() {
             @Override
             public void execute() {
-                setHeaderTexts(header.prependRow());
+                configureHeaderRow(header.prependRow());
             }
         }, menuPath);
         addMenuCommand("Append row", new ScheduledCommand() {
             @Override
             public void execute() {
-                setHeaderTexts(header.appendRow());
+                configureHeaderRow(header.appendRow());
             }
         }, menuPath);
         addMenuCommand("Remove top row", new ScheduledCommand() {
@@ -332,6 +332,42 @@ public class GridBasicClientFeatures extends
                 header.removeRow(header.getRowCount() - 1);
             }
         }, menuPath);
+
+    }
+
+    private void configureHeaderRow(final HeaderRow row) {
+        final GridHeader header = grid.getHeader();
+        setHeaderTexts(row);
+        String rowTitle = "Row " + header.getRowCount();
+        final String[] menuPath = { "Component", "Header", rowTitle };
+
+        addMenuCommand("Join column cells 0, 1", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(row.getCell(0), row.getCell(1));
+
+            }
+        }, menuPath);
+
+        addMenuCommand("Join columns 1, 2", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(grid.getColumn(1), grid.getColumn(2));
+
+            }
+        }, menuPath);
+
+        addMenuCommand("Join all columns", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(grid.getColumns().toArray(
+                        new GridColumn[grid.getColumnCount()]));
+
+            }
+        }, menuPath);
     }
 
     private void createFooterMenu() {
@@ -348,13 +384,13 @@ public class GridBasicClientFeatures extends
         addMenuCommand("Prepend row", new ScheduledCommand() {
             @Override
             public void execute() {
-                setFooterTexts(footer.prependRow());
+                configureFooterRow(footer.prependRow());
             }
         }, menuPath);
         addMenuCommand("Append row", new ScheduledCommand() {
             @Override
             public void execute() {
-                setFooterTexts(footer.appendRow());
+                configureFooterRow(footer.appendRow());
             }
         }, menuPath);
         addMenuCommand("Remove top row", new ScheduledCommand() {
@@ -371,6 +407,41 @@ public class GridBasicClientFeatures extends
         }, menuPath);
     }
 
+    private void configureFooterRow(final FooterRow row) {
+        final GridFooter footer = grid.getFooter();
+        setFooterTexts(row);
+        String rowTitle = "Row " + footer.getRowCount();
+        final String[] menuPath = { "Component", "Footer", rowTitle };
+
+        addMenuCommand("Join column cells 0, 1", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(row.getCell(0), row.getCell(1));
+
+            }
+        }, menuPath);
+
+        addMenuCommand("Join columns 1, 2", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(grid.getColumn(1), grid.getColumn(2));
+
+            }
+        }, menuPath);
+
+        addMenuCommand("Join all columns", new ScheduledCommand() {
+
+            @Override
+            public void execute() {
+                row.join(grid.getColumns().toArray(
+                        new GridColumn[grid.getColumnCount()]));
+
+            }
+        }, menuPath);
+    }
+
     /**
      * Creates a a renderer for a {@link Renderers}
      */