Add API for running BindingValidationStatusHandlers (#9966)

This patch adds an API to Binding for accessing the validation status handlers from a custom BinderValidationStatusHandler.

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

@@ -126,6 +126,15 @@ public class Binder<BEAN> implements Serializable {
          */
         public BindingValidationStatus<TARGET> validate();
 
+        /**
+         * Gets the validation status handler for this Binding.
+         * 
+         * @return the validation status handler for this binding
+         * 
+         * @since 8.2
+         */
+        public BindingValidationStatusHandler getValidationStatusHandler();
+
         /**
          * Unbinds the binding from its respective {@code Binder}
          * Removes any {@code ValueChangeListener} {@code Registration} from
@@ -134,7 +143,6 @@ public class Binder<BEAN> implements Serializable {
          * @since 8.2
          */
         public void unbind();
-
     }
 
     /**
@@ -990,8 +998,9 @@ public class Binder<BEAN> implements Serializable {
             return binder;
         }
 
-        private void notifyStatusHandler(BindingValidationStatus<?> status) {
-            statusHandler.statusChange(status);
+        @Override
+        public BindingValidationStatusHandler getValidationStatusHandler() {
+            return statusHandler;
         }
     }
 
@@ -1948,9 +1957,7 @@ public class Binder<BEAN> implements Serializable {
     protected void handleBinderValidationStatus(
             BinderValidationStatus<BEAN> binderStatus) {
         // let field events go to binding status handlers
-        binderStatus.getFieldValidationStatuses()
-                .forEach(status -> ((BindingImpl<?, ?, ?>) status.getBinding())
-                        .notifyStatusHandler(status));
+        binderStatus.notifyBindingValidationStatusHandlers();
 
         // show first possible error or OK status in the label if set
         if (getStatusLabel().isPresent()) {

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

@@ -23,6 +23,7 @@ import java.util.Objects;
 import java.util.stream.Collectors;
 
 import com.vaadin.data.Binder.BindingBuilder;
+import com.vaadin.server.SerializablePredicate;
 
 /**
  * Binder validation status change. Represents the outcome of binder level
@@ -33,8 +34,8 @@ import com.vaadin.data.Binder.BindingBuilder;
  * Note: if there are any field level validation errors, the bean level
  * validation is not run.
  * <p>
- * Use {@link Binder#setValidationStatusHandler(BinderValidationStatusHandler)} to handle
- * form level validation status changes.
+ * Use {@link Binder#setValidationStatusHandler(BinderValidationStatusHandler)}
+ * to handle form level validation status changes.
  *
  * @author Vaadin Ltd
  *
@@ -188,4 +189,34 @@ public class BinderValidationStatus<BEAN> implements Serializable {
         return binderStatuses.stream().filter(ValidationResult::isError)
                 .collect(Collectors.toList());
     }
+
+    /**
+     * Notifies all validation status handlers in bindings.
+     * 
+     * @see #notifyBindingValidationStatusHandlers(SerializablePredicate)
+     * 
+     * @since 8.2
+     */
+    public void notifyBindingValidationStatusHandlers() {
+        notifyBindingValidationStatusHandlers(t -> true);
+    }
+
+    /**
+     * Notifies validation status handlers for bindings that pass given filter.
+     * The filter should return {@code true} for each
+     * {@link BindingValidationStatus} that should be delegated to the status
+     * handler in the binding.
+     * 
+     * @see #notifyBindingValidationStatusHandlers()
+     * 
+     * @param filter
+     *            the filter to select bindings to run status handling for
+     * 
+     * @since 8.2
+     */
+    public void notifyBindingValidationStatusHandlers(
+            SerializablePredicate<BindingValidationStatus<?>> filter) {
+        bindingStatuses.stream().filter(filter).forEach(s -> s.getBinding()
+                .getValidationStatusHandler().statusChange(s));
+    }
 }

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

@@ -21,8 +21,9 @@ import com.vaadin.ui.AbstractComponent;
 /**
  * Handler for {@link BinderValidationStatus} changes.
  * <p>
- * {@link Binder#setValidationStatusHandler(BinderValidationStatusHandler) Register} an
- * instance of this class to be able to customize validation status handling.
+ * {@link Binder#setValidationStatusHandler(BinderValidationStatusHandler)
+ * Register} an instance of this class to be able to customize validation status
+ * handling.
  * <p>
  * The default handler will show
  * {@link AbstractComponent#setComponentError(com.vaadin.server.ErrorMessage) an
@@ -53,5 +54,4 @@ public interface BinderValidationStatusHandler<BEAN>
      *            the changed status
      */
     void statusChange(BinderValidationStatus<BEAN> statusChange);
-
 }

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

@@ -749,6 +749,68 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
                 String.valueOf(item.getAge()), ageField.getValue());
     }
 
+    static class MyBindingHandler implements BindingValidationStatusHandler {
+
+        boolean expectingError = false;
+        int callCount = 0;
+
+        @Override
+        public void statusChange(BindingValidationStatus<?> statusChange) {
+            ++callCount;
+            if (expectingError) {
+                Assert.assertTrue("Expecting error", statusChange.isError());
+            } else {
+                Assert.assertFalse("Unexpected error", statusChange.isError());
+            }
+        }
+    }
+
+    @Test
+    public void execute_binding_status_handler_from_binder_status_handler() {
+        MyBindingHandler bindingHandler = new MyBindingHandler();
+        binder.forField(nameField)
+                .withValidator(t -> !t.isEmpty(), "No empty values.")
+                .withValidationStatusHandler(bindingHandler)
+                .bind(Person::getFirstName, Person::setFirstName);
+
+        String ageError = "CONVERSIONERROR";
+        binder.forField(ageField)
+                .withConverter(new StringToIntegerConverter(ageError))
+                .bind(Person::getAge, Person::setAge);
+
+        binder.setValidationStatusHandler(status -> {
+            status.notifyBindingValidationStatusHandlers();
+        });
+
+        String initialName = item.getFirstName();
+        int initialAge = item.getAge();
+
+        binder.setBean(item);
+
+        // Test specific error handling.
+        bindingHandler.expectingError = true;
+        nameField.setValue("");
+
+        // Test default error handling.
+        ageField.setValue("foo");
+        Assert.assertTrue("Component error does not contain error message",
+                ageField.getComponentError().getFormattedHtmlMessage()
+                        .contains(ageError));
+
+        // Restore values and test no errors.
+        ageField.setValue(String.valueOf(initialAge));
+        Assert.assertNull("There should be no component error",
+                ageField.getComponentError());
+
+        bindingHandler.expectingError = false;
+        nameField.setValue(initialName);
+
+        // Assert that the handler was called.
+        Assert.assertEquals(
+                "Unexpected callCount to binding validation status handler", 4,
+                bindingHandler.callCount);
+    }
+      
     @Test
     public void removed_binding_not_updates_value() {
         Binding<Person, Integer> binding = binder.forField(ageField)
@@ -766,6 +828,5 @@ public class BinderTest extends BinderTestBase<Binder<Person>, Person> {
 
         Assert.assertEquals("Binding still affects bean even after unbind",
             ageBeforeUnbind, String.valueOf(item.getAge()));
-
     }
 }