Introduce Binder.addFialdValueChangeListener (#8273)

Fixes #8273

server/src/main/java/com/vaadin/data/Binder.java

@@ -39,6 +39,7 @@ import java.util.stream.Stream;
 import com.googlecode.gentyref.GenericTypeReflector;
 import com.vaadin.annotations.PropertyId;
 import com.vaadin.data.HasValue.ValueChangeEvent;
+import com.vaadin.data.HasValue.ValueChangeListener;
 import com.vaadin.data.converter.StringToIntegerConverter;
 import com.vaadin.data.validator.BeanValidator;
 import com.vaadin.event.EventRouter;
@@ -928,6 +929,7 @@ public class Binder<BEAN> implements Serializable {
                     binderValidationResults);
             getBinder().getValidationStatusHandler().statusChange(status);
             getBinder().fireStatusChangeEvent(status.hasErrors());
+            getBinder().fireValueChangeEvent(event);
         }
 
         /**
@@ -1734,6 +1736,29 @@ public class Binder<BEAN> implements Serializable {
                 StatusChangeListener.class.getDeclaredMethods()[0]);
     }
 
+    /**
+     * Adds field value change listener to all the fields in the binder.
+     * <p>
+     * Added listener is notified every time whenever any bound field value is
+     * changed. The same functionality can be achieved by adding a
+     * {@link ValueChangeListener} to all fields in the {@link Binder}.
+     * <p>
+     * The listener is added to all fields regardless of whether the method is
+     * invoked before or after field is bound.
+     * 
+     * @see ValueChangeEvent
+     * @see ValueChangeListener
+     *
+     * @param listener
+     *            a field value change listener
+     * @return a registration for the listener
+     */
+    public Registration addValueChangeListener(
+            ValueChangeListener<?> listener) {
+        return getEventRouter().addListener(ValueChangeEvent.class, listener,
+                ValueChangeListener.class.getDeclaredMethods()[0]);
+    }
+
     /**
      * Creates a new binding with the given field.
      *
@@ -2239,4 +2264,7 @@ public class Binder<BEAN> implements Serializable {
         return fieldName.toLowerCase(Locale.ENGLISH).replace("_", "");
     }
 
+    private <V> void fireValueChangeEvent(ValueChangeEvent<V> event) {
+        getEventRouter().fireEvent(event);
+    }
 }

server/src/test/java/com/vaadin/data/BinderValueChangeTest.java

@@ -0,0 +1,167 @@
+/*
+ * 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;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.vaadin.data.Binder.BindingBuilder;
+import com.vaadin.data.HasValue.ValueChangeEvent;
+import com.vaadin.data.converter.StringToIntegerConverter;
+import com.vaadin.tests.data.bean.Person;
+import com.vaadin.ui.TextField;
+
+/**
+ * @author Vaadin Ltd
+ *
+ */
+public class BinderValueChangeTest
+        extends BinderTestBase<Binder<Person>, Person> {
+
+    private AtomicReference<ValueChangeEvent<?>> event;
+
+    private static class TestTextField extends TextField {
+        @Override
+        protected boolean setValue(String value, boolean userOriginated) {
+            return super.setValue(value, userOriginated);
+        }
+    }
+
+    @Before
+    public void setUp() {
+        binder = new Binder<>();
+        item = new Person();
+        event = new AtomicReference<>();
+    }
+
+    @Test
+    public void unboundField_noEvents() {
+        binder.addValueChangeListener(this::statusChanged);
+
+        BindingBuilder<Person, String> binding = binder.forField(nameField);
+
+        nameField.setValue("");
+        Assert.assertNull(event.get());
+
+        binding.bind(Person::getFirstName, Person::setFirstName);
+        Assert.assertNull(event.get());
+    }
+
+    @Test
+    public void setBean_unbound_noEvents() {
+        binder.addValueChangeListener(this::statusChanged);
+
+        Assert.assertNull(event.get());
+
+        binder.setBean(item);
+
+        Assert.assertNull(event.get());
+    }
+
+    @Test
+    public void readBean_unbound_noEvents() {
+        binder.addValueChangeListener(this::statusChanged);
+
+        Assert.assertNull(event.get());
+
+        binder.readBean(item);
+
+        Assert.assertNull(event.get());
+    }
+
+    @Test
+    public void setValue_unbound_singleEventOnSetValue() {
+        binder.forField(nameField).bind(Person::getFirstName,
+                Person::setFirstName);
+        binder.forField(ageField)
+                .withConverter(new StringToIntegerConverter(""))
+                .bind(Person::getAge, Person::setAge);
+
+        binder.addValueChangeListener(this::statusChanged);
+
+        Assert.assertNull(event.get());
+        nameField.setValue("foo");
+        verifyEvent(nameField);
+    }
+
+    @Test
+    public void setValue_bound_singleEventOnSetValue() {
+        binder.forField(nameField).bind(Person::getFirstName,
+                Person::setFirstName);
+        binder.forField(ageField)
+                .withConverter(new StringToIntegerConverter(""))
+                .bind(Person::getAge, Person::setAge);
+        binder.setBean(item);
+
+        binder.addValueChangeListener(this::statusChanged);
+
+        Assert.assertNull(event.get());
+        nameField.setValue("foo");
+        verifyEvent(nameField);
+    }
+
+    @Test
+    public void userOriginatedUpdate_unbound_singleEventOnSetValue() {
+        TestTextField field = new TestTextField();
+
+        binder.forField(field).bind(Person::getFirstName, Person::setFirstName);
+        binder.forField(ageField)
+                .withConverter(new StringToIntegerConverter(""))
+                .bind(Person::getAge, Person::setAge);
+
+        binder.addValueChangeListener(this::statusChanged);
+
+        Assert.assertNull(event.get());
+        field.setValue("foo", true);
+        verifyEvent(field, true);
+    }
+
+    @Test
+    public void addListenerFirst_bound_singleEventOnSetValue() {
+        binder.addValueChangeListener(this::statusChanged);
+
+        binder.forField(nameField).bind(Person::getFirstName,
+                Person::setFirstName);
+        binder.forField(ageField)
+                .withConverter(new StringToIntegerConverter(""))
+                .bind(Person::getAge, Person::setAge);
+        binder.setBean(item);
+
+        Assert.assertNull(event.get());
+        ageField.setValue(String.valueOf(1));
+        verifyEvent(ageField);
+    }
+
+    private void verifyEvent(HasValue<?> field) {
+        verifyEvent(field, false);
+    }
+
+    private void verifyEvent(HasValue<?> field, boolean isUserOriginated) {
+        ValueChangeEvent<?> changeEvent = event.get();
+        Assert.assertNotNull(changeEvent);
+        Assert.assertEquals(field, changeEvent.getSource());
+        Assert.assertEquals(field, changeEvent.getComponent());
+        Assert.assertEquals(isUserOriginated, changeEvent.isUserOriginated());
+    }
+
+    private void statusChanged(ValueChangeEvent<?> evt) {
+        Assert.assertNull(event.get());
+        event.set(evt);
+    }
+}