Add Bindinding.setRequired

Shorthand for making field show required indicator and validating against empty.
Removes obsolete NotNullValidator and NotEmptyValidator. Latter is still used
in some tests, that why it is still in test packages.

Fixes vaadin/framework8-issues#29

Change-Id: Ib116739a20a0bbd1b1460423ee36ed2752c5496a

4 files changed, 140 insertions, 44 deletions

diff --git a/server/src/test/java/com/vaadin/data/BinderTest.java b/server/src/test/java/com/vaadin/data/BinderTest.java
index 6d33ab437b..22af7d2272 100644
--- a/server/src/test/java/com/vaadin/data/BinderTest.java
+++ b/server/src/test/java/com/vaadin/data/BinderTest.java
@@ -5,14 +5,18 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
+import java.util.Locale;
 import java.util.Objects;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 
+import com.vaadin.data.Binder.Binding;
 import com.vaadin.data.util.converter.StringToIntegerConverter;
-import com.vaadin.data.validator.NotNullValidator;
+import com.vaadin.data.validator.NotEmptyValidator;
+import com.vaadin.server.ErrorMessage;
 import com.vaadin.tests.data.bean.Person;
 import com.vaadin.tests.data.bean.Sex;
 import com.vaadin.ui.TextField;
@@ -310,7 +314,7 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
     public void withValidator_doesNotDisablesDefaulNullRepresentation() {
         String nullRepresentation = "foo";
         binder.forField(nameField).withNullRepresentation(nullRepresentation)
-                .withValidator(new NotNullValidator(""))
+                .withValidator(new NotEmptyValidator<>(""))
                 .bind(Person::getFirstName, Person::setFirstName);
         item.setFirstName(null);
         binder.setBean(item);
@@ -321,4 +325,64 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
         nameField.setValue(newValue);
         Assert.assertEquals(newValue, item.getFirstName());
     }
+
+    @Test
+    public void setRequired_withErrorMessage_fieldGetsRequiredIndicatorAndValidator() {
+        TextField textField = new TextField();
+        Assert.assertFalse(textField.isRequiredIndicatorVisible());
+
+        Binding<Person, String, String> binding = binder.forField(textField);
+        Assert.assertFalse(textField.isRequiredIndicatorVisible());
+
+        binding.setRequired("foobar");
+        Assert.assertTrue(textField.isRequiredIndicatorVisible());
+
+        binding.bind(Person::getFirstName, Person::setFirstName);
+        binder.setBean(item);
+        Assert.assertNull(textField.getErrorMessage());
+
+        textField.setValue(textField.getEmptyValue());
+        ErrorMessage errorMessage = textField.getErrorMessage();
+        Assert.assertNotNull(errorMessage);
+        Assert.assertEquals("foobar", errorMessage.getFormattedHtmlMessage());
+
+        textField.setValue("value");
+        Assert.assertNull(textField.getErrorMessage());
+        Assert.assertTrue(textField.isRequiredIndicatorVisible());
+    }
+
+    @Test
+    public void setRequired_withErrorMessageProvider_fieldGetsRequiredIndicatorAndValidator() {
+        TextField textField = new TextField();
+        textField.setLocale(Locale.CANADA);
+        Assert.assertFalse(textField.isRequiredIndicatorVisible());
+
+        Binding<Person, String, String> binding = binder.forField(textField);
+        Assert.assertFalse(textField.isRequiredIndicatorVisible());
+        AtomicInteger invokes = new AtomicInteger();
+
+        binding.setRequired(context -> {
+            invokes.incrementAndGet();
+            Assert.assertSame(Locale.CANADA, context.getLocale().get());
+            return "foobar";
+        });
+        Assert.assertTrue(textField.isRequiredIndicatorVisible());
+
+        binding.bind(Person::getFirstName, Person::setFirstName);
+        binder.setBean(item);
+        Assert.assertNull(textField.getErrorMessage());
+        Assert.assertEquals(0, invokes.get());
+
+        textField.setValue(textField.getEmptyValue());
+        ErrorMessage errorMessage = textField.getErrorMessage();
+        Assert.assertNotNull(errorMessage);
+        Assert.assertEquals("foobar", errorMessage.getFormattedHtmlMessage());
+        // validation is run twice, once for the field, then for all the fields
+        // for cross field validation...
+        Assert.assertEquals(2, invokes.get());
+
+        textField.setValue("value");
+        Assert.assertNull(textField.getErrorMessage());
+        Assert.assertTrue(textField.isRequiredIndicatorVisible());
+    }
 }
\ No newline at end of file
diff --git a/server/src/test/java/com/vaadin/data/validator/BeanValidatorTest.java b/server/src/test/java/com/vaadin/data/validator/BeanValidatorTest.java
index fb504eea65..97f767bbc7 100644
--- a/server/src/test/java/com/vaadin/data/validator/BeanValidatorTest.java
+++ b/server/src/test/java/com/vaadin/data/validator/BeanValidatorTest.java
@@ -3,6 +3,7 @@ package com.vaadin.data.validator;
 import java.util.Calendar;
 import java.util.Locale;
 
+import org.junit.After;
 import org.junit.Test;
 
 import com.vaadin.tests.data.bean.Address;
@@ -77,6 +78,11 @@ public class BeanValidatorTest extends ValidatorTestBase {
         assertPasses(null, validator("nickname"));
     }
 
+    @After
+    public void tearDown() {
+        UI.setCurrent(null);
+    }
+
     private BeanValidator validator(String propertyName) {
         return new BeanValidator(BeanToValidate.class, propertyName);
     }
diff --git a/server/src/test/java/com/vaadin/data/validator/NotEmptyValidator.java b/server/src/test/java/com/vaadin/data/validator/NotEmptyValidator.java
new file mode 100644
index 0000000000..61cacf8b51
--- /dev/null
+++ b/server/src/test/java/com/vaadin/data/validator/NotEmptyValidator.java
@@ -0,0 +1,68 @@
+/*
+ * 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.data.validator;
+
+import java.util.Objects;
+
+import com.vaadin.data.Binder.Binding;
+import com.vaadin.data.HasValue;
+import com.vaadin.data.ValidationResult;
+import com.vaadin.data.Validator;
+import com.vaadin.data.util.converter.ValueContext;
+
+/**
+ * Simple validator to check against {@code null} value and empty {@link String}
+ * value.
+ * <p>
+ * This validator works similar to {@link NotNullValidator} but in addition it
+ * also check whether the value is not an empty String.
+ * <p>
+ * This validator can be suitable for fields that have been marked as required
+ * with {@link HasValue#setRequiredIndicatorVisible(boolean)}.
+ * <p>
+ * Note that {@link Binding#setRequired(com.vaadin.data.ErrorMessageProvider)}
+ * does almost the same thing, but verifies against the value NOT being equal to
+ * what {@link HasValue#getEmptyValue()} returns and sets the required indicator
+ * visible with {@link HasValue#setRequiredIndicatorVisible(boolean)}.
+ *
+ * @see HasValue#setRequiredIndicatorVisible(boolean)
+ * @see Binding#setRequired(com.vaadin.data.ErrorMessageProvider)
+ * @author Vaadin Ltd
+ * @since 8.0
+ *
+ */
+public class NotEmptyValidator<T> implements Validator<T> {
+
+    private final String message;
+
+    /**
+     * @param message
+     *            error validation message
+     */
+    public NotEmptyValidator(String message) {
+        this.message = message;
+    }
+
+    @Override
+    public ValidationResult apply(T value, ValueContext context) {
+        if (Objects.isNull(value) || Objects.equals(value, "")) {
+            return ValidationResult.error(message);
+        } else {
+            return ValidationResult.ok();
+        }
+    }
+
+}
diff --git a/server/src/test/java/com/vaadin/data/validator/NotNullValidatorTest.java b/server/src/test/java/com/vaadin/data/validator/NotNullValidatorTest.java
deleted file mode 100644
index 24b95bf58a..0000000000
--- a/server/src/test/java/com/vaadin/data/validator/NotNullValidatorTest.java
+++ /dev/null
@@ -1,42 +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.data.validator;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import com.vaadin.data.ValidationResult;
-import com.vaadin.data.util.converter.ValueContext;
-
-public class NotNullValidatorTest {
-
-    @Test
-    public void nullValueIsDisallowed() {
-        NotNullValidator validator = new NotNullValidator("foo");
-        ValidationResult result = validator.apply(null, new ValueContext());
-        Assert.assertTrue(result.isError());
-        Assert.assertEquals("foo", result.getErrorMessage());
-    }
-
-    @Test
-    public void nonNullValueIsAllowed() {
-        NotNullValidator validator = new NotNullValidator("foo");
-        ValidationResult result = validator.apply("bar", new ValueContext());
-        Assert.assertFalse(result.isError());
-        Assert.assertFalse(result.isError());
-    }
-
-}