Add presentation value providers for Grid (#9553)

This patch changes Grid Columns, so they can have different value and presentation types. A presentation provider can be given when setting the renderer for a column. This provider takes the value of the column on a row and chooses what to present for this value. Using this approach it is easier to have an editor for the actual backing data instead of the presentation of it.

Fixes #8656
Resolves #9588

all/src/main/templates/release-notes.html

@@ -108,6 +108,8 @@
         <li>Tooltip styles for <tt>ContentMode.PREFORMATTED</tt> have been changed in all built-in themes to use the application font and allow long lines to wrap to multiple lines.</li>
         <li><tt>Grid.Column</tt> now extends <tt>AbstractExtension</tt> instead of <tt>AbstractGridExtension</tt> to hide data generator specific API.</li>
         <li><tt>DataCommunicator</tt>, <tt>DataKeyMapper</tt> and <tt>KeyMapper</tt> public APIs have some minor changes for better bean identification.</li>
+        <li><tt>Grid.createColumn</tt> now has one more parameter <tt>presentationProvider</tt>.</li>
+
         <h2>For incompatible or behaviour-altering changes in 8.0, please see <a href="https://vaadin.com/download/release/8.0/8.0.0/release-notes.html#incompatible">8.0 release notes</a></h2>
         
                 

documentation/components/components-grid.asciidoc

@@ -613,6 +613,7 @@ grid.addColumn(person -> {
       }, new ComponentRenderer());
 ----
 
+
 [[components.grid.renderer.custom]]
 === Custom Renderers
 
@@ -896,6 +897,34 @@ You can modify the error message by implementing a custom
 [interfacename]#EditorErrorGenerator# with for the [classname]#Editor#.
 
 
+[[components.grid.presentation.provider]]
+=== Presentation Value Providers
+
+By default, a renderer displays the column value. If you want to edit an
+internal value (such as an address object) but show a simpler representation
+when not editing a row, a presentation value provider can be used. 
+
+A presentation value provider converts the value of a cell (obtained with a
+value provider, and used by the editor) to a different representation to be
+shown by renderers when the cell is not being edited. A custom renderer can
+optionally be used for the presentation values.
+
+In the following example, we demonstrate one way to use a simplified
+presentation of an address column while allowing editing the full address:
+
+[source, java]
+----
+Column<Person, Address> column = grid.addColumn(Person::getAddress);
+// alternatively, the presentation provider can be given as an extra parameter
+// to addColumn()
+column.setRenderer(
+    address -> address.getCity() + " " + address.getCountry(),
+    new TextRenderer());
+column.setCaption("Address");
+column.setEditorComponent(new AddressField(), Person::setAddress);
+----
+
+
 ////
 // Not supported in 8
 [[components.grid.scrolling]]

server/src/main/java/com/vaadin/ui/Grid.java

@@ -822,6 +822,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
     public static class Column<T, V> extends AbstractExtension {
 
         private final ValueProvider<T, V> valueProvider;
+        private ValueProvider<V, ?> presentationProvider;
 
         private SortOrderProvider sortOrderProvider = direction -> {
             String id = getId();
@@ -846,22 +847,11 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
                 assert communicationId != null : "No communication ID set for column "
                         + state.caption;
 
-                @SuppressWarnings("unchecked")
-                Renderer<V> renderer = (Renderer<V>) state.renderer;
-
                 JsonObject obj = getDataObject(jsonObject,
                         DataCommunicatorConstants.DATA);
 
-                V providerValue = valueProvider.apply(item);
-
-                // Make Grid track components.
-                if (renderer instanceof ComponentRenderer
-                        && providerValue instanceof Component) {
-                    addComponent(item, (Component) providerValue);
-                }
-                JsonValue rendererValue = renderer.encode(providerValue);
-
-                obj.put(communicationId, rendererValue);
+                obj.put(communicationId, generateRendererValue(item,
+                        presentationProvider, state.renderer));
 
                 String style = styleGenerator.apply(item);
                 if (style != null && !style.isEmpty()) {
@@ -906,19 +896,48 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
          *            the function to get values from items, not
          *            <code>null</code>
          * @param renderer
-         *            the type of value, not <code>null</code>
+         *            the value renderer, not <code>null</code>
          */
         protected Column(ValueProvider<T, V> valueProvider,
                 Renderer<? super V> renderer) {
+            this(valueProvider, ValueProvider.identity(), renderer);
+        }
+
+        /**
+         * Constructs a new Column configuration with given renderer and value
+         * provider.
+         * <p>
+         * For a more complete explanation on presentation provider, see
+         * {@link #setRenderer(ValueProvider, Renderer)}.
+         *
+         * @param valueProvider
+         *            the function to get values from items, not
+         *            <code>null</code>
+         * @param presentationProvider
+         *            the function to get presentations from the value of this
+         *            column, not <code>null</code>. For more details, see {@link #setRenderer(ValueProvider, Renderer)}
+         * @param renderer
+         *            the presentation renderer, not <code>null</code>
+         * @param <P>
+         *            the presentation type
+         * 
+         * @since 8.1
+         */
+        protected <P> Column(ValueProvider<T, V> valueProvider,
+                ValueProvider<V, P> presentationProvider,
+                Renderer<? super P> renderer) {
             Objects.requireNonNull(valueProvider,
                     "Value provider can't be null");
+            Objects.requireNonNull(presentationProvider,
+                    "Presentation provider can't be null");
             Objects.requireNonNull(renderer, "Renderer can't be null");
 
             ColumnState state = getState();
 
             this.valueProvider = valueProvider;
-            state.renderer = renderer;
+            this.presentationProvider = presentationProvider;
 
+            state.renderer = renderer;
             state.caption = "";
 
             // Add the renderer as a child extension of this extension, thus
@@ -926,7 +945,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
             // removed
             addExtension(renderer);
 
-            Class<? super V> valueType = renderer.getPresentationType();
+            Class<? super P> valueType = renderer.getPresentationType();
 
             if (Comparable.class.isAssignableFrom(valueType)) {
                 comparator = (a, b) -> compareComparables(
@@ -1008,6 +1027,20 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
             }
         }
 
+        @SuppressWarnings("unchecked")
+        private <P> JsonValue generateRendererValue(T item,
+                ValueProvider<V, P> presentationProvider, Connector renderer) {
+            P presentationValue = presentationProvider
+                    .apply(valueProvider.apply(item));
+
+            // Make Grid track components.
+            if (renderer instanceof ComponentRenderer
+                    && presentationValue instanceof Component) {
+                addComponent(item, (Component) presentationValue);
+            }
+            return ((Renderer<P>) renderer).encode(presentationValue);
+        }
+
         private void addComponent(T item, Component component) {
             if (activeComponents.containsKey(item)) {
                 if (activeComponents.get(item).equals(component)) {
@@ -1887,7 +1920,39 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
          * @since 8.0.3
          */
         public Column<T, V> setRenderer(Renderer<? super V> renderer) {
-            Objects.requireNonNull(renderer, "Renderer can't be null");
+            return setRenderer(ValueProvider.identity(), renderer);
+        }
+
+        /**
+         * Sets the Renderer for this Column. Setting the renderer will cause
+         * all currently available row data to be recreated and sent to the
+         * client.
+         * <p>
+         * The presentation provider is a method that takes the value of this
+         * column on a single row, and maps that to a value that the renderer
+         * accepts. This feature can be used for storing a complex value in a
+         * column for editing, but providing a simplified presentation for the
+         * user when not editing.
+         *
+         * @param presentationProvider
+         *            the function to get presentations from the value of this
+         *            column, not {@code null}
+         * @param renderer
+         *            the new renderer, not {@code null}
+         * 
+         * @param <P>
+         *            the presentation type
+         * 
+         * @return this column
+         *
+         * @since 8.1
+         */
+        public <P> Column<T, V> setRenderer(
+                ValueProvider<V, P> presentationProvider,
+                Renderer<? super P> renderer) {
+            Objects.requireNonNull(renderer, "Renderer can not be null");
+            Objects.requireNonNull(presentationProvider,
+                    "Presentation provider can not be null");
 
             // Remove old renderer
             Connector oldRenderer = getState().renderer;
@@ -1898,6 +1963,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
             // Set new renderer
             getState().renderer = renderer;
             addExtension(renderer);
+            this.presentationProvider = presentationProvider;
 
             // Trigger redraw
             getGrid().getDataCommunicator().reset();
@@ -1911,8 +1977,8 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
          * @return the renderer
          * @since 8.1
          */
-        public Renderer<? super V> getRenderer() {
-            return (Renderer<? super V>) getState().renderer;
+        public Renderer<?> getRenderer() {
+            return (Renderer<?>) getState().renderer;
         }
 
         /**
@@ -1921,6 +1987,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
          * @return the grid that this column belongs to, or <code>null</code> if
          *         this column has not yet been associated with any grid
          */
+        @SuppressWarnings("unchecked")
         protected Grid<T> getGrid() {
             return (Grid<T>) getParent();
         }
@@ -2500,7 +2567,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
      * @param valueProvider
      *            the value provider
      * @param renderer
-     *            the column value class
+     *            the column value renderer
      * @param <V>
      *            the column value type
      *
@@ -2510,8 +2577,67 @@ 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) {
+        return addColumn(valueProvider, ValueProvider.identity(), renderer);
+    }
+
+    /**
+     * Adds a new column to this {@link Grid} with value provider and
+     * presentation provider.
+     * <p>
+     * <strong>Note:</strong> The presentation type for this method is set to be
+     * String. To use any custom renderer with the presentation provider, use
+     * {@link #addColumn(ValueProvider, ValueProvider, AbstractRenderer)}.
+     *
+     * @param valueProvider
+     *            the value provider
+     * @param presentationProvider
+     *            the value presentation provider
+     * @param <V>
+     *            the column value type
+     * 
+     * @see #addColumn(ValueProvider, ValueProvider, AbstractRenderer)
+     *
+     * @return the new column
+     * @since 8.1
+     */
+    public <V> Column<T, V> addColumn(ValueProvider<T, V> valueProvider,
+            ValueProvider<V, String> presentationProvider) {
+        return addColumn(valueProvider, presentationProvider,
+                new TextRenderer());
+    }
+
+    /**
+     * Adds a new column to this {@link Grid} with value provider, presentation
+     * provider and typed renderer.
+     * 
+     * <p>
+     * The presentation provider is a method that takes the value from the value
+     * provider, and maps that to a value that the renderer accepts. This
+     * feature can be used for storing a complex value in a column for editing,
+     * but providing a simplified presentation for the user when not editing.
+     *
+     * @param valueProvider
+     *            the value provider
+     * @param presentationProvider
+     *            the value presentation provider
+     * @param renderer
+     *            the column value renderer
+     * @param <V>
+     *            the column value type
+     * @param <P>
+     *            the column presentation type
+     *
+     * @return the new column
+     *
+     * @see AbstractRenderer
+     * @since 8.1
+     */
+    public <V, P> Column<T, V> addColumn(ValueProvider<T, V> valueProvider,
+            ValueProvider<V, P> presentationProvider,
+            AbstractRenderer<? super T, ? super P> renderer) {
         String generatedIdentifier = getGeneratedIdentifier();
-        Column<T, V> column = createColumn(valueProvider, renderer);
+        Column<T, V> column = createColumn(valueProvider, presentationProvider,
+                renderer);
         addColumn(generatedIdentifier, column);
         return column;
     }
@@ -2536,21 +2662,28 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
     }
 
     /**
-     * Creates a column instance from a value provider and a renderer.
+     * Creates a column instance from a value provider, presentation provider
+     * and a renderer.
      *
      * @param valueProvider
      *            the value provider
+     * @param presentationProvider
+     *            the presentation provider
      * @param renderer
      *            the renderer
      * @return a new column instance
      * @param <V>
      *            the column value type
+     * @param <P>
+     *            the column presentation type
      *
-     * @since 8.0.3
+     * @since 8.1
      */
-    protected <V> Column<T, V> createColumn(ValueProvider<T, V> valueProvider,
-            AbstractRenderer<? super T, ? super V> renderer) {
-        return new Column<>(valueProvider, renderer);
+    protected <V, P> Column<T, V> createColumn(
+            ValueProvider<T, V> valueProvider,
+            ValueProvider<V, P> presentationProvider,
+            AbstractRenderer<? super T, ? super P> renderer) {
+        return new Column<>(valueProvider, presentationProvider, renderer);
     }
 
     private void addColumn(String identifier, Column<T, ?> column) {
@@ -4019,7 +4152,8 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
                 column = addColumn(id);
             } else {
                 DeclarativeValueProvider<T> provider = new DeclarativeValueProvider<>();
-                column = createColumn(provider, new HtmlRenderer());
+                column = createColumn(provider, ValueProvider.identity(),
+                        new HtmlRenderer());
                 addColumn(getGeneratedIdentifier(), column);
                 if (id != null) {
                     column.setId(id);

uitest/src/main/java/com/vaadin/tests/components/grid/GridColumnPresentation.java

@@ -0,0 +1,99 @@
+package com.vaadin.tests.components.grid;
+
+import com.vaadin.data.HasValue;
+import com.vaadin.server.ErrorMessage;
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.shared.Registration;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.tests.data.bean.Address;
+import com.vaadin.tests.data.bean.Person;
+import com.vaadin.ui.Composite;
+import com.vaadin.ui.Grid;
+import com.vaadin.ui.Label;
+import com.vaadin.ui.renderers.TextRenderer;
+
+/**
+ * An example for using a different value and presentation types in a Grid
+ * column.
+ */
+public class GridColumnPresentation extends AbstractTestUI {
+
+    /**
+     * Dummy HasValue for Address.
+     */
+    private static class AddressField extends Composite
+            implements HasValue<Address> {
+
+        Address address;
+        private Label label;
+
+        public AddressField() {
+            super();
+
+            label = new Label();
+            setCompositionRoot(label);
+        }
+
+        @Override
+        public void setValue(Address value) {
+            Address oldAddress = address;
+            address = value;
+            label.setValue(String.valueOf(address));
+            fireEvent(new ValueChangeEvent<>(this, oldAddress, false));
+        }
+
+        @Override
+        public Address getValue() {
+            return address;
+        }
+
+        @Override
+        public Registration addValueChangeListener(
+                ValueChangeListener<Address> listener) {
+            return addListener(ValueChangeEvent.class, listener,
+                    ValueChangeListener.VALUE_CHANGE_METHOD);
+        }
+
+        @Override
+        public boolean isReadOnly() {
+            return super.isReadOnly();
+        }
+
+        @Override
+        public void setReadOnly(boolean readOnly) {
+            super.setReadOnly(readOnly);
+        }
+
+        @Override
+        public boolean isRequiredIndicatorVisible() {
+            return super.isRequiredIndicatorVisible();
+        }
+
+        @Override
+        public void setRequiredIndicatorVisible(boolean visible) {
+            super.setRequiredIndicatorVisible(visible);
+        }
+
+        @Override
+        public void setComponentError(ErrorMessage componentError) {
+            label.setComponentError(componentError);
+        }
+    }
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        Grid<Person> personGrid = new Grid<>();
+        personGrid.setItems(Person.createTestPerson1(),
+                Person.createTestPerson2());
+        personGrid.addColumn(Person::getAddress)
+                .setRenderer(
+                        address -> address.getCity() + " "
+                                + address.getCountry().name(),
+                        new TextRenderer())
+                .setCaption("Address")
+                .setEditorComponent(new AddressField(), Person::setAddress);
+        personGrid.getEditor().setEnabled(true);
+        addComponent(personGrid);
+    }
+
+}

uitest/src/test/java/com/vaadin/tests/components/grid/GridColumnPresentationTest.java

@@ -0,0 +1,27 @@
+package com.vaadin.tests.components.grid;
+
+import com.vaadin.testbench.elements.GridElement;
+import com.vaadin.testbench.parallel.TestCategory;
+import com.vaadin.tests.tb3.SingleBrowserTest;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+@TestCategory("grid")
+public class GridColumnPresentationTest extends SingleBrowserTest {
+
+    @Test
+    public void presenterAndEditor() {
+        openTestURL();
+        GridElement grid = $(GridElement.class).get(0);
+        assertEquals("Turku FINLAND", grid.getCell(0, 0).getText());
+        assertEquals("Amsterdam NETHERLANDS", grid.getCell(1, 0).getText());
+        //Activate editor
+        GridElement.GridCellElement cell = grid.getCell(1, 0);
+        cell.doubleClick();
+
+        assertEquals("Address [streetAddress=Red street, postalCode=12, city=Amsterdam, country=Netherlands]",
+                grid.getEditor().getField(0).getText());
+
+    }
+}