Extract Bean validation logic from Binder to BeanValidationBinder

Fixes #8253

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

@@ -30,9 +30,7 @@ import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
-import com.vaadin.data.Binder.BindingBuilder;
 import com.vaadin.data.util.BeanUtil;
-import com.vaadin.data.validator.BeanValidator;
 import com.vaadin.server.Setter;
 import com.vaadin.util.ReflectTools;
 
@@ -152,17 +150,6 @@ public class BeanBinderPropertySet<T> implements BinderPropertySet<T> {
                     .convertPrimitiveType(descriptor.getPropertyType());
         }
 
-        @Override
-        public BindingBuilder<T, V> beforeBind(
-                BindingBuilder<T, V> originalBuilder) {
-            if (BeanUtil.checkBeanValidationAvailable()) {
-                return originalBuilder.withValidator(new BeanValidator(
-                        getPropertySet().beanType, descriptor.getName()));
-            } else {
-                return originalBuilder;
-            }
-        }
-
         @Override
         public String getName() {
             return descriptor.getName();

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

@@ -0,0 +1,63 @@
+/*
+ * 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 com.vaadin.data.util.BeanUtil;
+import com.vaadin.data.validator.BeanValidator;
+
+/**
+ * @author Vaadin Ltd
+ * @see Binder
+ * @see HasValue
+ *
+ * @since 8.0
+ */
+public class BeanValidationBinder<BEAN> extends Binder<BEAN> {
+
+    private final Class<BEAN> beanType;
+
+    /**
+     * Creates a new binder that uses reflection based on the provided bean type
+     * to resolve bean properties. It assumes that JSR-303 bean validation
+     * implementation is present on the classpath. If there is no such
+     * implementation available then {@link Binder} class should be used instead
+     * (this constructor will throw an exception). Otherwise
+     * {@link BeanValidator} is added to each binding that is defined using a
+     * property name.
+     *
+     * @param beanType
+     *            the bean type to use, not <code>null</code>
+     */
+    public BeanValidationBinder(Class<BEAN> beanType) {
+        super(beanType);
+        if (!BeanUtil.checkBeanValidationAvailable()) {
+            throw new IllegalStateException(
+                    BeanValidationBinder.class.getSimpleName()
+                            + " cannot be used because a JSR-303 Bean Validation "
+                            + "implementation not found on the classpath. Use "
+                            + Binder.class.getSimpleName() + " instead");
+        }
+        this.beanType = beanType;
+    }
+
+    @Override
+    protected BindingBuilder<BEAN, ?> configureBinding(
+            BindingBuilder<BEAN, ?> binding,
+            BinderPropertyDefinition<BEAN, ?> definition) {
+        return binding.withValidator(
+                new BeanValidator(beanType, definition.getName()));
+    }
+}

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

@@ -619,13 +619,14 @@ public class Binder<BEAN> implements Serializable {
                         // Setter ignores value
                     });
 
-            BindingBuilder finalBinding = withConverter(
+            BindingBuilder<BEAN, ?> finalBinding = withConverter(
                     createConverter(definition.getType()), false);
 
-            finalBinding = definition.beforeBind(finalBinding);
+            finalBinding = getBinder().configureBinding(finalBinding,
+                    definition);
 
             try {
-                return finalBinding.bind(getter, setter);
+                return ((BindingBuilder) finalBinding).bind(getter, setter);
             } finally {
                 getBinder().boundProperties.add(propertyName);
                 getBinder().incompleteMemberFieldBindings.remove(getField());
@@ -1085,9 +1086,7 @@ public class Binder<BEAN> implements Serializable {
 
     /**
      * Creates a new binder that uses reflection based on the provided bean type
-     * to resolve bean properties. If a JSR-303 bean validation implementation
-     * is present on the classpath, a {@link BeanValidator} is added to each
-     * binding that is defined using a property name.
+     * to resolve bean properties.
      *
      * @param beanType
      *            the bean type to use, not <code>null</code>
@@ -1937,6 +1936,22 @@ public class Binder<BEAN> implements Serializable {
         return eventRouter;
     }
 
+    /**
+     * Configures the {@code binding} with the property definition
+     * {@code definition} before it's being bound.
+     * 
+     * @param binding
+     *            a binding to configure
+     * @param definition
+     *            a property definition information
+     * @return the new configured binding
+     */
+    protected BindingBuilder<BEAN, ?> configureBinding(
+            BindingBuilder<BEAN, ?> binding,
+            BinderPropertyDefinition<BEAN, ?> definition) {
+        return binding;
+    }
+
     private void doRemoveBean(boolean fireStatusEvent) {
         setHasChanges(false);
         if (bean != null) {

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

@@ -18,7 +18,6 @@ package com.vaadin.data;
 import java.io.Serializable;
 import java.util.Optional;
 
-import com.vaadin.data.Binder.BindingBuilder;
 import com.vaadin.server.Setter;
 
 /**
@@ -55,20 +54,6 @@ public interface BinderPropertyDefinition<T, V> extends Serializable {
      */
     public Class<V> getType();
 
-    /**
-     * Hook for modifying a binding before it is being bound to this property.
-     * This method can return the provided {@link BindingBuilder} as-is if no
-     * modifications are necessary.
-     *
-     * @param originalBuilder
-     *            the original binding builder that is being bound, not
-     *            <code>null</code>
-     * @return the binding builder to use for creating the binding, not
-     *         <code>null</code>
-     */
-    public BindingBuilder<T, V> beforeBind(
-            BindingBuilder<T, V> originalBuilder);
-
     /**
      * Gets the name of this property.
      *

server/src/main/java/com/vaadin/data/validator/BeanValidator.java

@@ -91,7 +91,7 @@ public class BeanValidator implements Validator<Object> {
         if (!BeanUtil.checkBeanValidationAvailable()) {
             throw new IllegalStateException("Cannot create a "
                     + BeanValidator.class.getSimpleName()
-                    + ": a JSR-303 Bean Validation implementation not found on theclasspath");
+                    + ": a JSR-303 Bean Validation implementation not found on the classpath");
         }
         Objects.requireNonNull(beanType, "bean class cannot be null");
         Objects.requireNonNull(propertyName, "property name cannot be null");

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

@@ -48,7 +48,7 @@ public class BeanBinderTest
 
     @Before
     public void setUp() {
-        binder = new Binder<>(BeanToValidate.class);
+        binder = new BeanValidationBinder<>(BeanToValidate.class);
         item = new BeanToValidate();
         item.setFirstname("Johannes");
         item.setAge(32);

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

@@ -23,7 +23,6 @@ import java.util.stream.Stream;
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.vaadin.data.Binder.BindingBuilder;
 import com.vaadin.server.Setter;
 import com.vaadin.ui.TextField;
 
@@ -60,12 +59,6 @@ public class BinderCustomPropertySetTest {
             return String.class;
         }
 
-        @Override
-        public BindingBuilder<Map<String, String>, String> beforeBind(
-                BindingBuilder<Map<String, String>, String> originalBuilder) {
-            return originalBuilder;
-        }
-
         @Override
         public String getName() {
             return name;

server/src/test/java/com/vaadin/data/Jsr303Test.java

@@ -98,6 +98,14 @@ public class Jsr303Test {
             // BeanToValidate : @Size(min = 3, max = 16) for the firstName
             nameField.setValue("a");
             assertEquals(nameField.getValue(), item.getFirstname());
+
+            try {
+                BeanValidationBinder<BeanToValidate> beanValidationBinder = new BeanValidationBinder<>(
+                        BeanToValidate.class);
+                Assert.fail();
+            } catch (IllegalStateException ignore) {
+                // an exception has to be thrown
+            }
         }
 
     }