Allow changing renderers after column creation (#8841)

Closes #8250

3 files changed, 94 insertions, 6 deletions

diff --git a/server/src/main/java/com/vaadin/ui/Grid.java b/server/src/main/java/com/vaadin/ui/Grid.java
index cfd0ff2006..19222d8c85 100644
--- a/server/src/main/java/com/vaadin/ui/Grid.java
+++ b/server/src/main/java/com/vaadin/ui/Grid.java
@@ -73,6 +73,7 @@ import com.vaadin.server.SerializableFunction;
 import com.vaadin.server.SerializableSupplier;
 import com.vaadin.server.Setter;
 import com.vaadin.server.VaadinServiceClassLoaderUtil;
+import com.vaadin.shared.Connector;
 import com.vaadin.shared.MouseEventDetails;
 import com.vaadin.shared.Registration;
 import com.vaadin.shared.data.DataCommunicatorConstants;
@@ -1814,6 +1815,34 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
         }
 
         /**
+         * Sets the Renderer for this Column. Setting the renderer will cause
+         * all currently available row data to be recreated and sent to the
+         * client.
+         *
+         * @param renderer
+         *            the new renderer
+         * @return this column
+         */
+        public Column<T, V> setRenderer(Renderer<? super V> renderer) {
+            Objects.requireNonNull(renderer, "Renderer can't be null");
+
+            // Remove old renderer
+            Connector oldRenderer = getState().renderer;
+            if (oldRenderer != null && oldRenderer instanceof Extension) {
+                removeExtension((Extension) oldRenderer);
+            }
+
+            // Set new renderer
+            getState().renderer = renderer;
+            addExtension(renderer);
+
+            // Trigger redraw
+            getParent().getDataCommunicator().reset();
+
+            return this;
+        }
+
+        /**
          * Gets the grid that this column belongs to.
          *
          * @return the grid that this column belongs to, or <code>null</code> if
@@ -2341,11 +2370,25 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
     public <V> Column<T, V> addColumn(ValueProvider<T, V> valueProvider,
             AbstractRenderer<? super T, ? super V> renderer) {
         String generatedIdentifier = getGeneratedIdentifier();
-        Column<T, V> column = new Column<>(valueProvider, renderer);
+        Column<T, V> column = createColumn(valueProvider, renderer);
         addColumn(generatedIdentifier, column);
         return column;
     }
 
+    /**
+     * Creates a column instance from a value provider and a renderer.
+     *
+     * @param valueProvider
+     *            the value provider
+     * @param renderer
+     *            the renderer
+     * @return a new column instance
+     */
+    protected <V> Column<T, V> createColumn(ValueProvider<T, V> valueProvider,
+            AbstractRenderer<? super T, ? super V> renderer) {
+        return new Column<>(valueProvider, renderer);
+    }
+
     private void addColumn(String identifier, Column<T, ?> column) {
         if (getColumns().contains(column)) {
             return;
diff --git a/server/src/main/java/com/vaadin/ui/TreeGrid.java b/server/src/main/java/com/vaadin/ui/TreeGrid.java
index f438df4e8f..46e6c99b59 100644
--- a/server/src/main/java/com/vaadin/ui/TreeGrid.java
+++ b/server/src/main/java/com/vaadin/ui/TreeGrid.java
@@ -19,21 +19,24 @@ import java.util.Collection;
 import java.util.Objects;
 import java.util.stream.Stream;
 
+import com.vaadin.data.ValueProvider;
 import com.vaadin.data.provider.DataProvider;
 import com.vaadin.data.provider.HierarchicalDataProvider;
 import com.vaadin.shared.ui.treegrid.NodeCollapseRpc;
 import com.vaadin.shared.ui.treegrid.TreeGridCommunicationConstants;
 import com.vaadin.shared.ui.treegrid.TreeGridState;
+import com.vaadin.ui.renderers.AbstractRenderer;
+import com.vaadin.ui.renderers.Renderer;
 
 import elemental.json.Json;
 import elemental.json.JsonObject;
 
 /**
  * A grid component for displaying hierarchical tabular data.
- * 
+ *
  * @author Vaadin Ltd
  * @since 8.1
- * 
+ *
  * @param <T>
  *            the grid bean type
  */
@@ -106,9 +109,12 @@ public class TreeGrid<T> extends Grid<T> {
      * <p>
      * Setting a hierarchy column by calling this method also sets the column to
      * be visible and not hidable.
-     * 
+     * <p>
+     * <strong>Note:</strong> Changing the Renderer of the hierarchy column is
+     * not supported.
+     *
      * @see Column#setId(String)
-     * 
+     *
      * @param id
      *            id of the column to use for displaying hierarchy
      */
@@ -137,7 +143,7 @@ public class TreeGrid<T> extends Grid<T> {
      * expanded, it will be collapsed.
      * <p>
      * Toggling expansion on a leaf item in the hierarchy will have no effect.
-     * 
+     *
      * @param item
      *            the item to toggle expansion for
      */
@@ -161,4 +167,24 @@ public class TreeGrid<T> extends Grid<T> {
         }
         return (HierarchicalDataProvider<T, ?>) dataProvider;
     }
+
+    @Override
+    protected <V> Column<T, V> createColumn(ValueProvider<T, V> valueProvider,
+            AbstractRenderer<? super T, ? super V> renderer) {
+        return new Column<T, V>(valueProvider, renderer) {
+
+            @Override
+            public com.vaadin.ui.Grid.Column<T, V> setRenderer(
+                    Renderer<? super V> renderer) {
+                // Disallow changing renderer for the hierarchy column
+                if (getInternalIdForColumn(this).equals(
+                        TreeGrid.this.getState(false).hierarchyColumnId)) {
+                    throw new IllegalStateException(
+                            "Changing the renderer of the hierarchy column is not allowed.");
+                }
+
+                return super.setRenderer(renderer);
+            }
+        };
+    }
 }
diff --git a/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridColumnTest.java b/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridColumnTest.java
new file mode 100644
index 0000000000..a928a48a08
--- /dev/null
+++ b/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridColumnTest.java
@@ -0,0 +1,19 @@
+package com.vaadin.tests.components.treegrid;
+
+import org.junit.Test;
+
+import com.vaadin.ui.TreeGrid;
+import com.vaadin.ui.renderers.TextRenderer;
+
+public class TreeGridColumnTest {
+
+    private TreeGrid<String> treeGrid = new TreeGrid<>();
+
+    @Test(expected = IllegalStateException.class)
+    public void testChangeRendererOfHierarchyColumn() {
+        treeGrid.addColumn(Object::toString).setId("foo");
+        treeGrid.setHierarchyColumn("foo");
+        // This should not be allowed.
+        treeGrid.getColumn("foo").setRenderer(new TextRenderer());
+    }
+}