feat: add server-side fallback parser (#6743)

Author: vursen

vaadin-date-picker-flow-parent/vaadin-date-picker-flow-integration-tests/src/main/java/com/vaadin/flow/component/datepicker/DatePickerFallbackParserPage.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2000-2024 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.flow.component.datepicker;
+
+import java.time.LocalDate;
+
+import com.vaadin.flow.component.html.Div;
+import com.vaadin.flow.component.html.NativeButton;
+import com.vaadin.flow.data.binder.Result;
+import com.vaadin.flow.router.Route;
+
+import elemental.json.Json;
+import elemental.json.JsonObject;
+
+@Route("vaadin-date-picker/fallback-parser")
+public class DatePickerFallbackParserPage extends Div {
+    public DatePickerFallbackParserPage() {
+        DatePicker datePicker = new DatePicker();
+        datePicker.setFallbackParser((s) -> {
+            if (s.equals("newyear")) {
+                return Result.ok(LocalDate.of(2024, 1, 1));
+            } else if (s.equals("exception")) {
+                throw new RuntimeException("Exception in fallback parser");
+            } else {
+                return Result.error("Invalid date format");
+            }
+        });
+
+        Div valueChangeLog = new Div();
+        valueChangeLog.setId("value-change-log");
+
+        datePicker.addValueChangeListener(event -> {
+            JsonObject record = Json.createObject();
+            record.put("eventFromClient", event.isFromClient());
+            record.put("eventOldValue", formatDate(event.getOldValue()));
+            record.put("eventNewValue", formatDate(event.getValue()));
+            record.put("componentValue", formatDate(datePicker.getValue()));
+            record.put("componentValueProperty",
+                    datePicker.getElement().getProperty("value", ""));
+
+            valueChangeLog.add(new Div(record.toString()));
+        });
+
+        NativeButton clearValueChangeLog = new NativeButton(
+                "Clear value change log", event -> {
+                    valueChangeLog.removeAll();
+                });
+        clearValueChangeLog.setId("clear-value-change-log");
+
+        NativeButton setValue = new NativeButton("Set value", event -> {
+            datePicker.setValue(LocalDate.now());
+        });
+
+        add(datePicker, valueChangeLog, clearValueChangeLog, setValue);
+    }
+
+    private String formatDate(LocalDate date) {
+        return date == null ? "" : date.toString();
+    }
+}

vaadin-date-picker-flow-parent/vaadin-date-picker-flow-integration-tests/src/test/java/com/vaadin/flow/component/datepicker/DatePickerFallbackParserIT.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2000-2024 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.flow.component.datepicker;
+
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.vaadin.flow.component.datepicker.testbench.DatePickerElement;
+import com.vaadin.flow.testutil.TestPath;
+import com.vaadin.testbench.TestBenchElement;
+import com.vaadin.tests.AbstractComponentIT;
+
+import elemental.json.Json;
+import elemental.json.JsonObject;
+
+@TestPath("vaadin-date-picker/fallback-parser")
+public class DatePickerFallbackParserIT extends AbstractComponentIT {
+    private DatePickerElement datePicker;
+    private TestBenchElement valueChangeLog;
+
+    @Before
+    public void init() {
+        open();
+        datePicker = $(DatePickerElement.class).first();
+        valueChangeLog = $("div").id("value-change-log");
+    }
+
+    @Test
+    public void enterShortcutValue_clearShortcutValue() {
+        datePicker.setInputValue("newyear");
+        assertValueChange("", "2024-01-01");
+        assertInputValue("1/1/2024");
+
+        datePicker.setInputValue("newyear");
+        assertNoValueChange();
+        assertInputValue("1/1/2024");
+
+        datePicker.setInputValue("");
+        assertValueChange("2024-01-01", "");
+        assertInputValue("");
+    }
+
+    @Test
+    public void enterUnparsableValue_enterShortcutValue() {
+        datePicker.setInputValue("foo");
+        assertNoValueChange();
+        assertInputValue("foo");
+
+        datePicker.setInputValue("newyear");
+        assertValueChange("", "2024-01-01");
+        assertInputValue("1/1/2024");
+    }
+
+    @Test
+    public void enterParsableValue_enterShortcutValue() {
+        datePicker.setInputValue("2/2/2000");
+        assertValueChange("", "2000-02-02");
+        assertInputValue("2/2/2000");
+
+        datePicker.setInputValue("newyear");
+        assertValueChange("2000-02-02", "2024-01-01");
+        assertInputValue("1/1/2024");
+    }
+
+    @Test
+    public void enterShortcutValueThrowingException_enterParsableValue() {
+        datePicker.setInputValue("exception");
+        assertNoValueChange();
+        assertInputValue("exception");
+
+        datePicker.setInputValue("2/2/2000");
+        assertValueChange("", "2000-02-02");
+        assertInputValue("2/2/2000");
+    }
+
+    private void assertValueChange(String expectedOldValue,
+            String expectedNewValue) {
+        List<TestBenchElement> records = valueChangeLog.$("div").all();
+        Assert.assertEquals("ValueChangeEvent should be fired only once", 1,
+                records.size());
+
+        JsonObject record = Json.parse(records.get(0).getText());
+
+        Assert.assertTrue("eventFromClient should be true",
+                record.getBoolean("eventFromClient"));
+        Assert.assertEquals("eventOldValue should contain old value",
+                expectedOldValue, record.getString("eventOldValue"));
+        Assert.assertEquals("eventNewValue should contain new value",
+                expectedNewValue, record.getString("eventNewValue"));
+        Assert.assertEquals("componentValue should contain new value",
+                expectedNewValue, record.getString("componentValue"));
+        Assert.assertEquals("componentValueProperty should contain new value",
+                expectedNewValue, record.getString("componentValueProperty"));
+
+        $("button").id("clear-value-change-log").click();
+    }
+
+    private void assertNoValueChange() {
+        Assert.assertEquals("", valueChangeLog.getText());
+    }
+
+    private void assertInputValue(String expected) {
+        Assert.assertEquals(expected, datePicker.getInputValue());
+    }
+}