Show empty selection caption in ComboBox (#9468)

Fixes #9079

client/src/main/java/com/vaadin/client/ui/VComboBox.java

@@ -243,12 +243,12 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             return $entry(function(e) {
                 var deltaX = e.deltaX ? e.deltaX : -0.5*e.wheelDeltaX;
                 var deltaY = e.deltaY ? e.deltaY : -0.5*e.wheelDeltaY;
-
+        
                 // IE8 has only delta y
                 if (isNaN(deltaY)) {
                     deltaY = -0.5*e.wheelDelta;
                 }
-
+        
                 @com.vaadin.client.ui.VComboBox.JsniUtil::moveScrollFromEvent(*)(widget, deltaX, deltaY, e, e.deltaMode);
             });
         }-*/;
@@ -1669,6 +1669,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
      * field even for filtering.
      */
     private boolean textInputEnabled = true;
+    private String emptySelectionCaption = "";
 
     private final DataReceivedHandler dataReceivedHandler = new DataReceivedHandler();
 
@@ -1949,7 +1950,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
         dataReceivedHandler.cancelPendingPostFiltering();
 
         currentSuggestion = null;
-        setText("");
+        setText(getEmptySelectionCaption());
         setSelectedItemIcon(null);
 
         if (!"".equals(selectedOptionKey) || selectedOptionKey != null) {
@@ -1958,6 +1959,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             connector.sendSelection(null);
             // currentPage = 0;
         }
+
         updatePlaceholder();
 
         suggestionPopup.hide();
@@ -2028,7 +2030,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
         if (selectedKey == null || "".equals(selectedKey)) {
             currentSuggestion = null; // #13217
             selectedOptionKey = null;
-            setText("");
+            setText(getEmptySelectionCaption());
         }
         // some item selected
         for (ComboBoxSuggestion suggestion : currentSuggestions) {
@@ -2305,7 +2307,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
 
         // just fetch selected information from state
         String text = connector.getState().selectedItemCaption;
-        setText(text == null ? "" : text);
+        setText(text == null ? getEmptySelectionCaption() : text);
         setSelectedItemIcon(connector.getState().selectedItemIcon);
         selectedOptionKey = (connector.getState().selectedItemKey);
         if (selectedOptionKey == null || "".equals(selectedOptionKey)) {
@@ -2820,4 +2822,27 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
     public boolean getNullSelectionItemShouldBeVisible() {
         return nullSelectionAllowed && "".equals(lastFilter);
     }
+
+    /**
+     * Gets the empty selection caption.
+     * 
+     * @return the empty selection caption
+     */
+    public String getEmptySelectionCaption() {
+        return emptySelectionCaption;
+    }
+
+    /**
+     * Sets the empty selection caption for this VComboBox. The text is
+     * displayed in the text input when nothing is selected.
+     * 
+     * @param emptySelectionCaption
+     *            the empty selection caption
+     */
+    public void setEmptySelectionCaption(String emptySelectionCaption) {
+        this.emptySelectionCaption = emptySelectionCaption;
+        if (selectedOptionKey == null) {
+            setText(emptySelectionCaption);
+        }
+    }
 }

client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java

@@ -105,9 +105,11 @@ public class ComboBoxConnector extends AbstractListingConnector
             suggestions.remove(0);
             addEmptySelectionItem();
         }
+        getWidget().setEmptySelectionCaption(getState().emptySelectionCaption);
     }
 
-    @OnStateChange({ "selectedItemKey", "selectedItemCaption", "selectedItemIcon" })
+    @OnStateChange({ "selectedItemKey", "selectedItemCaption",
+            "selectedItemIcon" })
     private void onSelectionChange() {
         getDataReceivedHandler().updateSelectionFromServer(
                 getState().selectedItemKey, getState().selectedItemCaption,

uitest/src/main/java/com/vaadin/tests/components/combobox/ComboBoxEmptyCaption.java

@@ -18,6 +18,7 @@ package com.vaadin.tests.components.combobox;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
+import com.vaadin.annotations.Widgetset;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.tests.components.AbstractTestUI;
 import com.vaadin.ui.Button;
@@ -27,6 +28,7 @@ import com.vaadin.ui.ComboBox;
  * @author Vaadin Ltd
  *
  */
+@Widgetset("com.vaadin.DefaultWidgetSet")
 public class ComboBoxEmptyCaption extends AbstractTestUI {
 
     @Override

uitest/src/main/java/com/vaadin/tests/components/combobox/ComboBoxSelecting.java

@@ -3,12 +3,14 @@ package com.vaadin.tests.components.combobox;
 import java.util.ArrayList;
 import java.util.List;
 
+import com.vaadin.annotations.Widgetset;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.tests.components.AbstractReindeerTestUI;
 import com.vaadin.ui.ComboBox;
 import com.vaadin.ui.Label;
 import com.vaadin.ui.TextField;
 
+@Widgetset("com.vaadin.DefaultWidgetSet")
 public class ComboBoxSelecting extends AbstractReindeerTestUI {
     protected ComboBox<String> comboBox;
     protected List<String> items = new ArrayList<>();

uitest/src/test/java/com/vaadin/tests/components/combobox/ComboBoxEmptyCaptionTest.java

@@ -21,6 +21,8 @@ import java.util.Arrays;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
+import org.openqa.selenium.Keys;
+import org.openqa.selenium.interactions.Actions;
 
 import com.vaadin.testbench.elements.ButtonElement;
 import com.vaadin.testbench.elements.ComboBoxElement;
@@ -74,11 +76,27 @@ public class ComboBoxEmptyCaptionTest extends MultiBrowserTest {
                 "item6", "item7", "item8", "item9", "item10");
     }
 
+    @Test
+    public void emptyItemCaptionInTextBox() {
+        ComboBoxElement combo = $(ComboBoxElement.class).first();
+
+        Assert.assertEquals("", combo.getInputField().getAttribute("value"));
+
+        // set some caption for the empty selection element
+        $(ButtonElement.class).first().click();
+
+        Assert.assertEquals("empty",
+                combo.getInputField().getAttribute("value"));
+
+    }
+
     private void ensureSuggestions(ComboBoxElement element,
             String... suggestions) {
         element.openPopup();
-        System.out.println(element.getPopupSuggestions());
         Assert.assertEquals(Arrays.asList(suggestions),
                 new ArrayList<>(element.getPopupSuggestions()));
+        // Close popup
+        new Actions(getDriver()).sendKeys(Keys.ESCAPE).perform();
     }
+
 }