Remove HasValue from Grid

Extracts grid single selection into separate class, which
is an extension like in V7. Using an extension makes it
possible to easily add multiselect and no-select modes back,
and support custom selection models.

Adds Grid:asSingleSelect() SingleSelect so that grid can be
used as a Select in a binder.

Removes all remaining references to SelectionModels in Listings.
Renames SingleSelectionChangeEvent to SingleSelectionEvent, because
then it is unified with selection listener and MultiSelectionEvent.

Fixes vaadin/framework8-issues#424
Fixes vaadin/framework8-issues#425

Change-Id: Ie22bef29cfd4336c3f65d4e63531c578b8dd76a3

4 files changed, 96 insertions, 114 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 ef715acfad..f5d95dfa80 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
@@ -21,7 +21,6 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.Set;
 import java.util.stream.Collectors;
 
 import com.google.gwt.dom.client.Element;
@@ -40,7 +39,6 @@ import com.vaadin.client.annotations.OnStateChange;
 import com.vaadin.client.connectors.AbstractListingConnector;
 import com.vaadin.client.connectors.grid.ColumnConnector.CustomColumn;
 import com.vaadin.client.data.DataSource;
-import com.vaadin.client.data.SelectionModel;
 import com.vaadin.client.ui.SimpleManagedLayout;
 import com.vaadin.client.widget.grid.CellReference;
 import com.vaadin.client.widget.grid.EventCellReference;
@@ -58,8 +56,6 @@ import com.vaadin.client.widgets.Grid.FooterRow;
 import com.vaadin.client.widgets.Grid.HeaderCell;
 import com.vaadin.client.widgets.Grid.HeaderRow;
 import com.vaadin.shared.MouseEventDetails;
-import com.vaadin.shared.data.DataCommunicatorConstants;
-import com.vaadin.shared.data.selection.SelectionServerRpc;
 import com.vaadin.shared.data.sort.SortDirection;
 import com.vaadin.shared.ui.Connect;
 import com.vaadin.shared.ui.grid.GridConstants;
@@ -204,33 +200,6 @@ public class GridConnector extends AbstractListingConnector
         /* Item click events */
         getWidget().addBodyClickHandler(itemClickHandler);
         getWidget().addBodyDoubleClickHandler(itemClickHandler);
-        getWidget().setSelectionModel(new SelectionModel<JsonObject>() {
-
-            @Override
-            public void select(JsonObject item) {
-                getRpcProxy(SelectionServerRpc.class)
-                        .select(item.getString(DataCommunicatorConstants.KEY));
-            }
-
-            @Override
-            public void deselect(JsonObject item) {
-                getRpcProxy(SelectionServerRpc.class).deselect(
-                        item.getString(DataCommunicatorConstants.KEY));
-            }
-
-            @Override
-            public Set<JsonObject> getSelectedItems() {
-                throw new UnsupportedOperationException(
-                        "Selected item not known on the client side");
-            }
-
-            @Override
-            public boolean isSelected(JsonObject item) {
-                return item.hasKey(DataCommunicatorConstants.SELECTED)
-                        && item.getBoolean(DataCommunicatorConstants.SELECTED);
-            }
-
-        });
 
         layout();
     }
diff --git a/client/src/main/java/com/vaadin/client/connectors/grid/SingleSelectionModelConnector.java b/client/src/main/java/com/vaadin/client/connectors/grid/SingleSelectionModelConnector.java
new file mode 100644
index 0000000000..0a30dfa070
--- /dev/null
+++ b/client/src/main/java/com/vaadin/client/connectors/grid/SingleSelectionModelConnector.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.client.connectors.grid;
+
+import java.util.Set;
+
+import com.vaadin.client.ServerConnector;
+import com.vaadin.client.data.SelectionModel;
+import com.vaadin.client.extensions.AbstractExtensionConnector;
+import com.vaadin.shared.data.DataCommunicatorConstants;
+import com.vaadin.shared.data.selection.SelectionServerRpc;
+import com.vaadin.shared.ui.Connect;
+
+import elemental.json.JsonObject;
+
+/**
+ * Client side connector for grid single selection model.
+ *
+ * @author Vaadin Ltd.
+ *
+ * @since 8.0
+ */
+@Connect(com.vaadin.ui.components.grid.SingleSelectionModel.class)
+public class SingleSelectionModelConnector extends AbstractExtensionConnector {
+
+    @Override
+    protected void extend(ServerConnector target) {
+        getParent().getWidget()
+                .setSelectionModel(new SelectionModel<JsonObject>() {
+
+                    @Override
+                    public void select(JsonObject item) {
+                        getRpcProxy(SelectionServerRpc.class).select(
+                                item.getString(DataCommunicatorConstants.KEY));
+                    }
+
+                    @Override
+                    public void deselect(JsonObject item) {
+                        getRpcProxy(SelectionServerRpc.class).deselect(
+                                item.getString(DataCommunicatorConstants.KEY));
+                    }
+
+                    @Override
+                    public Set<JsonObject> getSelectedItems() {
+                        throw new UnsupportedOperationException(
+                                "Selected item not known on the client side");
+                    }
+
+                    @Override
+                    public boolean isSelected(JsonObject item) {
+                        return SelectionModel.isItemSelected(item);
+                    }
+
+                });
+    }
+
+    @Override
+    public GridConnector getParent() {
+        return (GridConnector) super.getParent();
+    }
+
+}
diff --git a/client/src/main/java/com/vaadin/client/connectors/selection/AbstractSelectionConnector.java b/client/src/main/java/com/vaadin/client/connectors/selection/AbstractSelectionConnector.java
deleted file mode 100644
index 55ce2dee7b..0000000000
--- a/client/src/main/java/com/vaadin/client/connectors/selection/AbstractSelectionConnector.java
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * Copyright 2000-2016 Vaadin Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
- */
-package com.vaadin.client.connectors.selection;
-
-import com.vaadin.client.ServerConnector;
-import com.vaadin.client.connectors.AbstractListingConnector;
-import com.vaadin.client.extensions.AbstractExtensionConnector;
-import com.vaadin.shared.data.DataCommunicatorConstants;
-
-import elemental.json.JsonObject;
-
-/**
- * The client-side connector for selection extensions.
- *
- * @author Vaadin Ltd.
- * 
- * @since 8.0
- */
-public abstract class AbstractSelectionConnector
-        extends AbstractExtensionConnector {
-
-    @Override
-    @SuppressWarnings("unchecked")
-    protected void extend(ServerConnector target) {
-        if (!(target instanceof AbstractListingConnector)) {
-            throw new IllegalArgumentException(
-                    "Cannot extend a connector that is not an "
-                            + AbstractListingConnector.class.getSimpleName());
-        }
-    }
-
-    @Override
-    @SuppressWarnings("unchecked")
-    public AbstractListingConnector getParent() {
-        return (AbstractListingConnector) super.getParent();
-    }
-
-    /**
-     * Gets the selected state from a given json object. This is a helper method
-     * for selection model connectors.
-     *
-     * @param item
-     *            a json object
-     * @return {@code true} if the json object is marked as selected;
-     *         {@code false} if not
-     */
-    public static boolean isItemSelected(JsonObject item) {
-        return item.hasKey(DataCommunicatorConstants.SELECTED)
-                && item.getBoolean(DataCommunicatorConstants.SELECTED);
-    }
-
-    /**
-     * Gets the item key from given json object. This is a helper method for
-     * selection model connectors.
-     *
-     * @param item
-     *            a json object
-     * @return item key; {@code null} if there is no key
-     */
-    public static String getKey(JsonObject item) {
-        if (item.hasKey(DataCommunicatorConstants.KEY)) {
-            return item.getString(DataCommunicatorConstants.KEY);
-        } else {
-            return null;
-        }
-    }
-
-}
diff --git a/client/src/main/java/com/vaadin/client/data/SelectionModel.java b/client/src/main/java/com/vaadin/client/data/SelectionModel.java
index 80eb20fef1..4079140128 100644
--- a/client/src/main/java/com/vaadin/client/data/SelectionModel.java
+++ b/client/src/main/java/com/vaadin/client/data/SelectionModel.java
@@ -17,6 +17,10 @@ package com.vaadin.client.data;
 
 import java.util.Set;
 
+import com.vaadin.shared.data.DataCommunicatorConstants;
+
+import elemental.json.JsonObject;
+
 /**
  * Models the selection logic of a {@code Grid} component. Determines how items
  * can be selected and deselected.
@@ -32,7 +36,7 @@ public interface SelectionModel<T> {
     /**
      * Selects the given item. If another item was already selected, that item
      * is deselected.
-     * 
+     *
      * @param item
      *            the item to select, not null
      */
@@ -50,7 +54,7 @@ public interface SelectionModel<T> {
     /**
      * Returns a set of the currently selected items. It is safe to invoke other
      * {@code SelectionModel} methods while iterating over the set.
-     * 
+     *
      * @return the items in the current selection, not null
      */
     Set<T> getSelectedItems();
@@ -70,4 +74,19 @@ public interface SelectionModel<T> {
     default void deselectAll() {
         getSelectedItems().forEach(this::deselect);
     }
+
+    /**
+     * Gets the selected state from a given grid row json object. This is a
+     * helper method for grid selection models.
+     *
+     * @param item
+     *            a json object
+     * @return {@code true} if the json object is marked as selected;
+     *         {@code false} if not
+     */
+    public static boolean isItemSelected(JsonObject item) {
+        return item.hasKey(DataCommunicatorConstants.SELECTED)
+                && item.getBoolean(DataCommunicatorConstants.SELECTED);
+    }
+
 }