Reintroduce reordering of grid columns

Change-Id: If8a23427ef5500a0177081c4be8065d2d5a0ca4c

3 files changed, 79 insertions, 3 deletions

diff --git a/client/src/main/java/com/vaadin/client/connectors/grid/GridConnector.java b/client/src/main/java/com/vaadin/client/connectors/grid/GridConnector.java
index 6596137d9d..02909e1fc3 100644
--- a/client/src/main/java/com/vaadin/client/connectors/grid/GridConnector.java
+++ b/client/src/main/java/com/vaadin/client/connectors/grid/GridConnector.java
@@ -20,7 +20,9 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.EventTarget;
@@ -132,7 +134,7 @@ public class GridConnector
      *            the id of the column to get
      * @return the column with the given id
      */
-    public Column<?, ?> getColumn(String columnId) {
+    public Column<?, JsonObject> getColumn(String columnId) {
         return idToColumn.get(columnId);
     }
 
@@ -180,6 +182,16 @@ public class GridConnector
                         getColumnId(event.getColumn()), event.isHidden());
             }
         });
+        getWidget().addColumnReorderHandler(event -> {
+            if (event.isUserOriginated()) {
+                List<String> newColumnOrder = mapColumnsToIds(
+                        event.getNewColumnOrder());
+                List<String> oldColumnOrder = mapColumnsToIds(
+                        event.getOldColumnOrder());
+                getRpcProxy(GridServerRpc.class)
+                        .columnsReordered(newColumnOrder, oldColumnOrder);
+            }
+        });
         getWidget().addColumnResizeHandler(event -> {
             Column<?, JsonObject> column = event.getColumn();
             getRpcProxy(GridServerRpc.class).columnResized(getColumnId(column),
@@ -219,6 +231,13 @@ public class GridConnector
         layout();
     }
 
+    @SuppressWarnings("unchecked")
+    @OnStateChange("columnOrder")
+    void updateColumnOrder() {
+        getWidget().setColumnOrder(getState().columnOrder.stream()
+                .map(this::getColumn).toArray(size -> new Column[size]));
+    }
+
     /**
      * Updates the grid header section on state change.
      */
@@ -446,4 +465,9 @@ public class GridConnector
         }
         return false;
     }
+
+    private List<String> mapColumnsToIds(List<Column<?, JsonObject>> columns) {
+        return columns.stream().map(this::getColumnId).filter(Objects::nonNull)
+                .collect(Collectors.toList());
+    }
 }
diff --git a/client/src/main/java/com/vaadin/client/widget/grid/events/ColumnReorderEvent.java b/client/src/main/java/com/vaadin/client/widget/grid/events/ColumnReorderEvent.java
index 72c0eb5878..0063c20b28 100644
--- a/client/src/main/java/com/vaadin/client/widget/grid/events/ColumnReorderEvent.java
+++ b/client/src/main/java/com/vaadin/client/widget/grid/events/ColumnReorderEvent.java
@@ -15,7 +15,10 @@
  */
 package com.vaadin.client.widget.grid.events;
 
+import java.util.List;
+
 import com.google.gwt.event.shared.GwtEvent;
+import com.vaadin.client.widgets.Grid.Column;
 
 /**
  * An event for notifying that the columns in the Grid have been reordered.
@@ -37,6 +40,48 @@ public class ColumnReorderEvent<T> extends GwtEvent<ColumnReorderHandler<T>> {
         return TYPE;
     }
 
+    private final List<Column<?, T>> oldColumnOrder;
+
+    private final List<Column<?, T>> newColumnOrder;
+
+    private final boolean userOriginated;
+
+    public ColumnReorderEvent(List<Column<?, T>> oldColumnOrder,
+            List<Column<?, T>> newColumnOrder, boolean userOriginated) {
+        this.oldColumnOrder = oldColumnOrder;
+        this.newColumnOrder = newColumnOrder;
+        this.userOriginated = userOriginated;
+    }
+
+    /**
+     * Gets the ordering of columns prior to this event.
+     *
+     * @return the list of columns in the grid's order prior to this event
+     */
+    public List<Column<?, T>> getOldColumnOrder() {
+        return oldColumnOrder;
+    }
+
+    /**
+     * Gets the new ordering of columns.
+     *
+     * @return the list of columns in the grid's current order
+     */
+    public List<Column<?, T>> getNewColumnOrder() {
+        return newColumnOrder;
+    }
+
+    /**
+     * Check whether this event originated from the user reordering columns or
+     * via API call.
+     *
+     * @return {@code true} if columns were reordered by the user, {@code false}
+     *         if not
+     */
+    public boolean isUserOriginated() {
+        return userOriginated;
+    }
+
     @SuppressWarnings({ "rawtypes", "unchecked" })
     @Override
     public Type<ColumnReorderHandler<T>> getAssociatedType() {
diff --git a/client/src/main/java/com/vaadin/client/widgets/Grid.java b/client/src/main/java/com/vaadin/client/widgets/Grid.java
index eac958fdce..7d6c1369b8 100644
--- a/client/src/main/java/com/vaadin/client/widgets/Grid.java
+++ b/client/src/main/java/com/vaadin/client/widgets/Grid.java
@@ -4372,7 +4372,7 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
 
                 Column<?, T>[] array = reordered
                         .toArray(new Column[reordered.size()]);
-                setColumnOrder(array);
+                setColumnOrder(true, array);
                 transferCellFocusOnDrop();
             } // else no reordering
         }
@@ -8171,6 +8171,12 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
      *            array of columns in wanted order
      */
     public void setColumnOrder(Column<?, T>... orderedColumns) {
+        setColumnOrder(false, orderedColumns);
+    }
+
+    private void setColumnOrder(boolean isUserOriginated,
+            Column<?, T>... orderedColumns) {
+        List<Column<?, T>> oldOrder = new ArrayList<>(columns);
         ColumnConfiguration conf = getEscalator().getColumnConfiguration();
 
         // Trigger ComplexRenderer.destroy for old content
@@ -8221,7 +8227,8 @@ public class Grid<T> extends ResizeComposite implements HasSelectionHandlers<T>,
 
         columnHider.updateTogglesOrder();
 
-        fireEvent(new ColumnReorderEvent<T>());
+        fireEvent(new ColumnReorderEvent<T>(oldOrder, newOrder,
+                isUserOriginated));
     }
 
     /**