Add methods to control validation

- Enable / disable all validators on Binder level
- Enable / disable validators on Binding level
- add writeBeanAsDraft(bean,boolean) for writing draft bean with validators disabled

Fixes: #5030

flow-data/src/main/java/com/vaadin/flow/data/binder/Binder.java

@@ -235,6 +235,21 @@ default BindingValidationStatus<TARGET> validate() {
          *         {@code true} otherwise (default)
          */
         public boolean isAsRequiredEnabled();
+
+        /**
+         * Define whether validators are disabled or enabled for this
+         * specific binding.
+         *
+         * @param validatorsDisabled A boolean value
+         */
+        public void setValidatorsDisabled(boolean validatorsDisabled);
+
+        /**
+         * Returns if validators are currently disabled or not
+         *
+         * @return A boolean value
+         */
+        public boolean isValidatorsDisabled();
     }
 
     /**
@@ -754,6 +769,7 @@ protected static class BindingBuilderImpl<BEAN, FIELDVALUE, TARGET>
         private final HasValue<?, FIELDVALUE> field;
         private BindingValidationStatusHandler statusHandler;
         private boolean isStatusHandlerChanged;
+        private Binding<BEAN, TARGET> binding;
 
         private boolean bound;
 
@@ -815,6 +831,7 @@ public Binding<BEAN, TARGET> bind(ValueProvider<BEAN, TARGET> getter,
             if (getBinder().incompleteBindings != null) {
                 getBinder().incompleteBindings.remove(getField());
             }
+            this.binding = binding;
 
             return binding;
         }
@@ -849,6 +866,7 @@ public Binding<BEAN, TARGET> bind(String propertyName) {
                 Binding binding = ((BindingBuilder) finalBinding).bind(getter,
                         setter);
                 getBinder().boundProperties.put(propertyName, binding);
+                this.binding = binding;
                 return binding;
             } finally {
                 if (getBinder().incompleteMemberFieldBindings != null) {
@@ -872,8 +890,17 @@ public BindingBuilder<BEAN, TARGET> withValidator(
             checkUnbound();
             Objects.requireNonNull(validator, "validator cannot be null");
 
+            Validator<? super TARGET> wrappedValidator = ((value, context) -> {
+                if (getBinder().isValidatorsDisabled() ||
+                        (binding != null && binding.isValidatorsDisabled())) {
+                    return ValidationResult.ok();
+                } else {
+                    return validator.apply(value, context);
+                }
+            });
+
             converterValidatorChain = ((Converter<FIELDVALUE, TARGET>) converterValidatorChain)
-                    .chain(new ValidatorAsConverter<>(validator));
+                    .chain(new ValidatorAsConverter<>(wrappedValidator));
             return this;
         }
 
@@ -1026,6 +1053,8 @@ protected static class BindingImpl<BEAN, FIELDVALUE, TARGET>
 
         private final boolean asRequiredSet;
 
+        private boolean validatorsDisabled = false;
+
         public BindingImpl(BindingBuilderImpl<BEAN, FIELDVALUE, TARGET> builder,
                 ValueProvider<BEAN, TARGET> getter,
                 Setter<BEAN, TARGET> setter) {
@@ -1306,6 +1335,16 @@ public void setAsRequiredEnabled(boolean asRequiredEnabled) {
         public boolean isAsRequiredEnabled() {
             return field.isRequiredIndicatorVisible();
         }
+
+        @Override
+        public void setValidatorsDisabled(boolean validatorsDisabled) {
+            this.validatorsDisabled = validatorsDisabled;			
+        }
+
+        @Override
+        public boolean isValidatorsDisabled() {
+            return validatorsDisabled;
+        }
     }
 
     /**
@@ -1412,6 +1451,8 @@ void setIdentity() {
 
     private Set<Binding<BEAN, ?>> changedBindings = new LinkedHashSet<>();
 
+    private boolean validatorsDisabled = false;
+
     /**
      * Creates a binder using a custom {@link PropertySet} implementation for
      * finding and resolving property names for
@@ -1831,7 +1872,27 @@ public void writeBean(BEAN bean) throws ValidationException {
      *            {@code null}
      */
     public void writeBeanAsDraft(BEAN bean) {
-        doWriteDraft(bean, new ArrayList<>(bindings));
+        doWriteDraft(bean, new ArrayList<>(bindings),false);
+    }
+
+    /**
+     * Writes successfully converted changes from the bound fields bypassing
+     * all the Validation or all fields passing conversion if forced = true.
+     * If the conversion fails, the value written to the bean will be null.
+     *
+     * @see #writeBean(Object)
+     * @see #writeBeanIfValid(Object)
+     * @see #readBean(Object)
+     * @see #setBean(Object)
+     *
+     * @param bean
+     *            the object to which to write the field values, not
+     *            {@code null}
+     * @param forced
+     *            disable all Validators during write
+     */
+    public void writeBeanAsDraft(BEAN bean, boolean forced) {    	 
+        doWriteDraft(bean, new ArrayList<>(bindings),true);
     }
 
     /**
@@ -1929,14 +1990,24 @@ private BinderValidationStatus<BEAN> doWriteIfValid(BEAN bean,
      *            the bean to write field values into
      * @param bindings
      *            the set of bindings to write to the bean
+     * @param forced
+     *            disable validators during write if true
      */
     @SuppressWarnings({ "unchecked" })
-    private void doWriteDraft(BEAN bean,
-            Collection<Binding<BEAN, ?>> bindings) {
+    private void doWriteDraft(BEAN bean, 
+            Collection<Binding<BEAN, ?>> bindings, boolean forced) {
         Objects.requireNonNull(bean, "bean cannot be null");
 
-        bindings.forEach(binding -> ((BindingImpl<BEAN, ?, ?>) binding)
-                .writeFieldValue(bean));
+        if (!forced) {
+             bindings.forEach(binding -> ((BindingImpl<BEAN, ?, ?>) binding)
+                    .writeFieldValue(bean));
+        } else {
+            boolean isDisabled = isValidatorsDisabled();
+            setValidatorsDisabled(true);
+            bindings.forEach(binding -> ((BindingImpl<BEAN, ?, ?>) binding)
+                    .writeFieldValue(bean));
+            setValidatorsDisabled(isDisabled);
+        }
     }
 
     /**
@@ -1998,7 +2069,14 @@ protected void restoreBeanState(BEAN bean,
      */
     public Binder<BEAN> withValidator(Validator<? super BEAN> validator) {
         Objects.requireNonNull(validator, "validator cannot be null");
-        validators.add(validator);
+        Validator<? super BEAN> wrappedValidator = ((value, context) -> {
+            if (isValidatorsDisabled()) {
+                return ValidationResult.ok();
+            } else {
+                return validator.apply(value, context);
+            }
+        });
+        validators.add(wrappedValidator);
         return this;
     }
 
@@ -2986,4 +3064,24 @@ public void removeBinding(String propertyName) {
         Optional.ofNullable(boundProperties.get(propertyName))
                 .ifPresent(Binding::unbind);
     }
+
+    /**
+     * Control whether validators including bean level validators are
+     * disabled or enabled globally for this Binder.
+     * 
+     * @param validatorsDisabled Boolean value
+     */
+    public void setValidatorsDisabled(boolean validatorsDisabled) {
+        this.validatorsDisabled = validatorsDisabled;
+    }
+
+    /**
+     * Returns if the validators including bean level validators
+     * are disabled or enabled for this Binder.
+     * 
+     * @return Boolean value
+     */
+    public boolean isValidatorsDisabled() {
+        return validatorsDisabled;
+    }
 }