Binder (Vaadin Platform (vaadin-platform-javadoc) 13.0.5 API)

java.lang.Object
- com.vaadin.flow.data.binder.Binder<BEAN>

Type Parameters:

BEAN - the bean type

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

BeanValidationBinder
```
public class Binder<BEAN>
extends Object
implements Serializable
```
Connects one or more Field components to properties of a backing data type such as a bean type. With a binder, input components can be grouped together into forms to easily create and update business objects with little explicit logic needed to move data between the UI and the data layers of the application.
A binder is a collection of bindings, each representing the mapping of a single field, through converters and validators, to a backing property.
A binder instance can be bound to a single bean instance at a time, but can be rebound as needed. This allows usage patterns like a master-details view, where a select component is used to pick the bean to edit.
Bean level validators can be added using the withValidator(Validator) method and will be run on the bound bean once it has been updated from the values of the bound fields. Bean level validators are also run as part of writeBean(Object) and writeBeanIfValid(Object) if all field level validators pass.
Note: For bean level validators, the bean must be updated before the validators are run. If a bean level validator fails in writeBean(Object) or writeBeanIfValid(Object), the bean will be reverted to the previous state before returning from the method. You should ensure that the getters/setters in the bean do not have side effects.
Unless otherwise specified, Binder method arguments cannot be null.

Since:

1.0.

Author:

Vaadin Ltd

See Also:

Binder.BindingBuilder, Binder.Binding, HasValue, Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static interface`	`Binder.Binding<BEAN,TARGET>` Represents the binding between a field and a data property.
`static interface`	`Binder.BindingBuilder<BEAN,TARGET>` Creates a binding between a field and a data property.
`protected static class`	`Binder.BindingBuilderImpl<BEAN,FIELDVALUE,TARGET>` An internal implementation of `BindingBuilder`.
`protected static class`	`Binder.BindingImpl<BEAN,FIELDVALUE,TARGET>` An internal implementation of `Binding`.

Constructor Summary

Constructors
Modifier	Constructor and Description
	`Binder()` Creates a new binder without support for creating bindings based on property names.
	`Binder(Class<BEAN> beanType)` Creates a new binder that uses reflection based on the provided bean type to resolve bean properties.
	`Binder(Class<BEAN> beanType, boolean scanNestedDefinitions)` Creates a new binder that uses reflection based on the provided bean type to resolve bean properties.
`protected`	`Binder(PropertySet<BEAN> propertySet)` Creates a binder using a custom `PropertySet` implementation for finding and resolving property names for `bindInstanceFields(Object)`, `bind(HasValue, String)` and `Binder.BindingBuilder.bind(String)`.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected <T> Registration`	`addListener(Class<T> eventType, SerializableConsumer<T> method)` Adds a listener to the binder.
`Registration`	`addStatusChangeListener(StatusChangeListener listener)` Adds status change listener to the binder.
`Registration`	`addValueChangeListener(HasValue.ValueChangeListener<? super HasValue.ValueChangeEvent<?>> listener)` Adds field value change listener to all the fields in the binder.
`<FIELDVALUE> Binder.Binding<BEAN,FIELDVALUE>`	`bind(HasValue<?,FIELDVALUE> field, String propertyName)` Binds the given field to the property with the given name.
`<FIELDVALUE> Binder.Binding<BEAN,FIELDVALUE>`	`bind(HasValue<?,FIELDVALUE> field, ValueProvider<BEAN,FIELDVALUE> getter, Setter<BEAN,FIELDVALUE> setter)` Binds a field to a bean property represented by the given getter and setter pair.
`void`	`bindInstanceFields(Object objectWithMemberFields)` Binds member fields found in the given object.
`protected void`	`clearError(HasValue<?,?> field)` Clears the error condition of the given field, if any.
`protected Binder.BindingBuilder<BEAN,?>`	`configureBinding(Binder.BindingBuilder<BEAN,?> binding, PropertyDefinition<BEAN,?> definition)` Configures the `binding` with the property definition `definition` before it's being bound.
`protected <FIELDVALUE,TARGET> Binder.BindingBuilder<BEAN,TARGET>`	`createBinding(HasValue<?,FIELDVALUE> field, Converter<FIELDVALUE,TARGET> converter, BindingValidationStatusHandler handler)` Creates a new binding with the given field.
`protected <FIELDVALUE,TARGET> Binder.BindingBuilder<BEAN,TARGET>`	`doCreateBinding(HasValue<?,FIELDVALUE> field, Converter<FIELDVALUE,TARGET> converter, BindingValidationStatusHandler handler)`
`<FIELDVALUE> Binder.BindingBuilder<BEAN,FIELDVALUE>`	`forField(HasValue<?,FIELDVALUE> field)` Creates a new binding for the given field.
`<FIELDVALUE> Binder.BindingBuilder<BEAN,FIELDVALUE>`	`forMemberField(HasValue<?,FIELDVALUE> field)` Creates a new binding for the given field.
`BEAN`	`getBean()` Returns the bean that has been bound with `bind(com.vaadin.flow.component.HasValue<?, FIELDVALUE>, com.vaadin.flow.function.ValueProvider<BEAN, FIELDVALUE>, com.vaadin.flow.data.binder.Setter<BEAN, FIELDVALUE>)`, or null if a bean is not currently bound.
`protected Map<Binder.Binding<BEAN,?>,Object>`	`getBeanState(BEAN bean, Collection<Binder.Binding<BEAN,?>> bindings)` Stores the state of the given bean.
`Optional<Binder.Binding<BEAN,?>>`	`getBinding(String propertyName)` Gets the binding for a property name.
`protected Collection<Binder.BindingImpl<BEAN,?,?>>`	`getBindings()` Returns the bindings for this binder.
`Stream<HasValue<?,?>>`	`getFields()` Returns the fields this binder has been bound to.
`Optional<HasText>`	`getStatusLabel()` Gets the status label or an empty optional if none has been set.
`BinderValidationStatusHandler<BEAN>`	`getValidationStatusHandler()` Gets the status handler of this form.
`protected void`	`handleBinderValidationStatus(BinderValidationStatus<BEAN> binderStatus)` The default binder level status handler.
`protected void`	`handleError(HasValue<?,?> field, ValidationResult result)` Handles a validation error emitted when trying to write the value of the given field.
`protected void`	`handleFieldValueChange(Binder.Binding<BEAN,?> binding)` Informs the Binder that a value in Binding was changed.
`protected void`	`handleValidationStatus(BindingValidationStatus<?> status)` Default `BindingValidationStatusHandler` functional method implementation.
`boolean`	`hasChanges()` Check whether any of the bound fields' have uncommitted changes since last explicit call to `readBean(Object)`, `removeBean()`, `writeBean(Object)` or `writeBeanIfValid(Object)`.
`boolean`	`isValid()` Runs all currently configured field level validators, as well as all bean level validators if a bean is currently set with `setBean(Object)`, and returns whether any of the validators failed.
`void`	`readBean(BEAN bean)` Reads the bound property values from the given bean to the corresponding fields.
`void`	`removeBean()` Removes the currently set bean and clears bound fields.
`void`	`removeBinding(Binder.Binding<BEAN,?> binding)` Removes the given Binding from this Binder.
`void`	`removeBinding(HasValue<?,?> field)` Finds and removes all Bindings for the given field.
`void`	`removeBinding(String propertyName)` Finds and removes the Binding for the given property name.
`protected void`	`removeBindingInternal(Binder.Binding<BEAN,?> binding)` Removes (internally) the `Binding` from the bound properties map (if present) and from the list of `Binding`s.
`protected void`	`restoreBeanState(BEAN bean, Map<Binder.Binding<BEAN,?>,Object> oldValues)` Restores the state of the bean from the given values.
`void`	`setBean(BEAN bean)` Binds the given bean to all the fields added to this Binder.
`void`	`setReadOnly(boolean readOnly)` Sets the read only state to the given value for all currently bound fields.
`void`	`setStatusLabel(HasText statusLabel)` Sets the label to show the binder level validation errors not related to any specific field.
`void`	`setValidationStatusHandler(BinderValidationStatusHandler<BEAN> statusHandler)` Sets the status handler to track form status changes.
`BinderValidationStatus<BEAN>`	`validate()` Validates the values of all bound fields and returns the validation status.
`protected BinderValidationStatus<BEAN>`	`validate(boolean fireEvent)` Validates the values of all bound fields and returns the validation status.
`static <BEAN> Binder<BEAN>`	`withPropertySet(PropertySet<BEAN> propertySet)` Creates a binder using a custom `PropertySet` implementation for finding and resolving property names for `bindInstanceFields(Object)`, `bind(HasValue, String)` and `Binder.BindingBuilder.bind(String)`.
`Binder<BEAN>`	`withValidator(SerializablePredicate<BEAN> predicate, ErrorMessageProvider errorMessageProvider)` A convenience method to add a validator to this binder using the `Validator.from(SerializablePredicate, ErrorMessageProvider)` factory method.
`Binder<BEAN>`	`withValidator(SerializablePredicate<BEAN> predicate, String message)` A convenience method to add a validator to this binder using the `Validator.from(SerializablePredicate, String)` factory method.
`Binder<BEAN>`	`withValidator(Validator<? super BEAN> validator)` Adds an bean level validator.
`void`	`writeBean(BEAN bean)` Writes changes from the bound fields to the given bean if all validators (binding and bean level) pass.
`boolean`	`writeBeanIfValid(BEAN bean)` Writes changes from the bound fields to the given bean if all validators (binding and bean level) pass.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Binder
```
protected Binder(PropertySet<BEAN> propertySet)
```
  Creates a binder using a custom PropertySet implementation for finding and resolving property names for bindInstanceFields(Object), bind(HasValue, String) and Binder.BindingBuilder.bind(String).
  
  Parameters:
  
  propertySet - the property set implementation to use, not null.
- Binder
```
public Binder(Class<BEAN> beanType)
```
  Creates a new binder that uses reflection based on the provided bean type to resolve bean properties.
  
  Parameters:
  
  beanType - the bean type to use, not null
- Binder
```
public Binder()
```
  Creates a new binder without support for creating bindings based on property names. Use an alternative constructor, such as Binder(Class), to create a binder that support creating bindings based on instance fields through bindInstanceFields(Object), or based on a property name through bind(HasValue, String) or Binder.BindingBuilder.bind(String).
- Binder
```
public Binder(Class<BEAN> beanType,
              boolean scanNestedDefinitions)
```
  Creates a new binder that uses reflection based on the provided bean type to resolve bean properties.
  
  Parameters:
  
  beanType - the bean type to use, not null
  
  scanNestedDefinitions - if true, scan for nested property definitions as well

Method Detail

withPropertySet
```
public static <BEAN> Binder<BEAN> withPropertySet(PropertySet<BEAN> propertySet)
```
Creates a binder using a custom PropertySet implementation for finding and resolving property names for bindInstanceFields(Object), bind(HasValue, String) and Binder.BindingBuilder.bind(String).
This functionality is provided as static method instead of as a public constructor in order to make it possible to use a custom property set without creating a subclass while still leaving the public constructors focused on the common use cases.

Type Parameters:

BEAN - the bean type

Parameters:

propertySet - the property set implementation to use, not null.

Returns:

a new binder using the provided property set, not null

See Also:

Binder(), Binder(Class)

handleFieldValueChange
```
protected void handleFieldValueChange(Binder.Binding<BEAN,?> binding)
```
Informs the Binder that a value in Binding was changed. This method will trigger validating and writing of the whole bean if using setBean(Object). If using readBean(Object) only the field validation is run.

Parameters:

binding - the binding whose value has been changed

getBean
```
public BEAN getBean()
```
Returns the bean that has been bound with bind(com.vaadin.flow.component.HasValue<?, FIELDVALUE>, com.vaadin.flow.function.ValueProvider<BEAN, FIELDVALUE>, com.vaadin.flow.data.binder.Setter<BEAN, FIELDVALUE>), or null if a bean is not currently bound.

Returns:

the currently bound bean if any

forField
```
public <FIELDVALUE> Binder.BindingBuilder<BEAN,FIELDVALUE> forField(HasValue<?,FIELDVALUE> field)
```
Creates a new binding for the given field. The returned builder may be further configured before invoking Binder.BindingBuilder.bind(ValueProvider, Setter) which completes the binding. Until Binding.bind is called, the binding has no effect.
Note: Not all HasValue implementations support passing null as the value. For these the Binder will automatically change null to a null representation provided by HasValue.getEmptyValue(). This conversion is one-way only, if you want to have a two-way mapping back to null, use Binder.BindingBuilder.withNullRepresentation(Object).

Type Parameters:

FIELDVALUE - the value type of the field

Parameters:

field - the field to be bound, not null

Returns:

the new binding

See Also:

bind(HasValue, ValueProvider, Setter)

forMemberField
```
public <FIELDVALUE> Binder.BindingBuilder<BEAN,FIELDVALUE> forMemberField(HasValue<?,FIELDVALUE> field)
```
Creates a new binding for the given field. The returned builder may be further configured before invoking bindInstanceFields(Object). Unlike with the forField(HasValue) method, no explicit call to Binder.BindingBuilder.bind(String) is needed to complete this binding in the case that the name of the field matches a field name found in the bean.

Type Parameters:

FIELDVALUE - the value type of the field

Parameters:

field - the field to be bound, not null

Returns:

the new binding builder

See Also:

forField(HasValue), bindInstanceFields(Object)

bind
```
public <FIELDVALUE> Binder.Binding<BEAN,FIELDVALUE> bind(HasValue<?,FIELDVALUE> field,
                                                         ValueProvider<BEAN,FIELDVALUE> getter,
                                                         Setter<BEAN,FIELDVALUE> setter)
```
Binds a field to a bean property represented by the given getter and setter pair. The functions are used to update the field value from the property and to store the field value to the property, respectively.
Use the forField(HasValue) overload instead if you want to further configure the new binding.
Note: Not all HasValue implementations support passing null as the value. For these the Binder will automatically change null to a null representation provided by HasValue.getEmptyValue(). This conversion is one-way only, if you want to have a two-way mapping back to null, use forField(HasValue) and Binder.BindingBuilder.withNullRepresentation(Object).
When a bean is bound with setBean(Object), the field value is set to the return value of the given getter. The property value is then updated via the given setter whenever the field value changes. The setter may be null; in that case the property value is never updated and the binding is said to be read-only.
If the Binder is already bound to some bean, the newly bound field is associated with the corresponding bean property as described above.
The getter and setter can be arbitrary functions, for instance implementing user-defined conversion or validation. However, in the most basic use case you can simply pass a pair of method references to this method as follows:
```
 class Person {
     public String getName() { ... }
     public void setName(String name) { ... }
 }

 TextField nameField = new TextField();
 binder.bind(nameField, Person::getName, Person::setName);
 
```
Note: when a null setter is given the field will be marked as read-only by invoking (HasValue.setReadOnly(boolean).
Type Parameters:

FIELDVALUE - the value type of the field

Parameters:

field - the field to bind, not null

getter - the function to get the value of the property to the field, not null

setter - the function to write the field value to the property or null if read-only

Returns:

the newly created binding

bind
```
public <FIELDVALUE> Binder.Binding<BEAN,FIELDVALUE> bind(HasValue<?,FIELDVALUE> field,
                                                         String propertyName)
```
Binds the given field to the property with the given name. The getter and setter of the property are looked up using a PropertySet.
For a Binder created using the Binder(Class) constructor, introspection will be used to find a Java Bean property. If a JSR-303 bean validation implementation is present on the classpath, a BeanValidator is also added to the binding.
The property must have an accessible getter method. It need not have an accessible setter; in that case the property value is never updated and the binding is said to be read-only.

Type Parameters:

FIELDVALUE - the value type of the field to bind

Parameters:

field - the field to bind, not null

propertyName - the name of the property to bind, not null

Returns:

the newly created binding

Throws:

IllegalArgumentException - if the property name is invalid

IllegalArgumentException - if the property has no accessible getter

IllegalStateException - if the binder is not configured with an appropriate PropertySet

See Also:

bind(HasValue, ValueProvider, Setter)

setBean
```
public void setBean(BEAN bean)
```
Binds the given bean to all the fields added to this Binder. A null value removes a currently bound bean.
When a bean is bound, the field values are updated by invoking their corresponding getter functions. Any changes to field values are reflected back to their corresponding property values of the bean as long as the bean is bound.
Any change made in the fields also runs validation for the field Binder.Binding and bean level validation for this binder (bean level validators are added using withValidator(Validator).
After updating each field, the value is read back from the field and the bean's property value is updated if it has been changed from the original value by the field or a converter.

Parameters:

bean - the bean to edit, or null to remove a currently bound bean and clear bound fields

See Also:

readBean(Object), writeBean(Object), writeBeanIfValid(Object)

removeBean
```
public void removeBean()
```
Removes the currently set bean and clears bound fields. If there is no bound bean, does nothing.
This is a shorthand for setBean(Object) with null bean.

readBean
```
public void readBean(BEAN bean)
```
Reads the bound property values from the given bean to the corresponding fields.
The bean is not otherwise associated with this binder; in particular its property values are not bound to the field value changes. To achieve that, use setBean(Object).

Parameters:

bean - the bean whose property values to read or null to clear bound fields

See Also:

setBean(Object), writeBeanIfValid(Object), writeBean(Object)

writeBean
```
public void writeBean(BEAN bean)
               throws ValidationException
```
Writes changes from the bound fields to the given bean if all validators (binding and bean level) pass.
If any field binding validator fails, no values are written and a ValidationException is thrown.
If all field level validators pass, the given bean is updated and bean level validators are run on the updated bean. If any bean level validator fails, the bean updates are reverted and a ValidationException is thrown.

Parameters:

bean - the object to which to write the field values, not null

Throws:

ValidationException - if some of the bound field values fail to validate

See Also:

writeBeanIfValid(Object), readBean(Object), setBean(Object)

writeBeanIfValid
```
public boolean writeBeanIfValid(BEAN bean)
```
Writes changes from the bound fields to the given bean if all validators (binding and bean level) pass.
If any field binding validator fails, no values are written and false is returned.
If all field level validators pass, the given bean is updated and bean level validators are run on the updated bean. If any bean level validator fails, the bean updates are reverted and false is returned.

Parameters:

bean - the object to which to write the field values, not null

Returns:

true if there was no validation errors and the bean was updated, false otherwise

See Also:

writeBean(Object), readBean(Object), setBean(Object)

restoreBeanState

protected void restoreBeanState(BEAN bean,
                                Map<Binder.Binding<BEAN,?>,Object> oldValues)

Restores the state of the bean from the given values.

Parameters:: bean - the bean; oldValues - the old values

getBeanState

protected Map<Binder.Binding<BEAN,?>,Object> getBeanState(BEAN bean,
                                                          Collection<Binder.Binding<BEAN,?>> bindings)

Stores the state of the given bean.

Parameters:: bean - the bean to store the state of; bindings - the bindings to store
Returns:: map from binding to value

withValidator
```
public Binder<BEAN> withValidator(Validator<? super BEAN> validator)
```
Adds an bean level validator.
Bean level validators are applied on the bean instance after the bean is updated. If the validators fail, the bean instance is reverted to its previous state.

Parameters:

validator - the validator to add, not null

Returns:

this binder, for chaining

See Also:

writeBean(Object), writeBeanIfValid(Object), withValidator(SerializablePredicate, String), withValidator(SerializablePredicate, ErrorMessageProvider)

withValidator
```
public Binder<BEAN> withValidator(SerializablePredicate<BEAN> predicate,
                                  String message)
```
A convenience method to add a validator to this binder using the Validator.from(SerializablePredicate, String) factory method.
Bean level validators are applied on the bean instance after the bean is updated. If the validators fail, the bean instance is reverted to its previous state.

Parameters:

predicate - the predicate performing validation, not null

message - the error message to report in case validation failure

Returns:

this binder, for chaining

See Also:

writeBean(Object), writeBeanIfValid(Object), withValidator(Validator), withValidator(SerializablePredicate, ErrorMessageProvider)

withValidator
```
public Binder<BEAN> withValidator(SerializablePredicate<BEAN> predicate,
                                  ErrorMessageProvider errorMessageProvider)
```
A convenience method to add a validator to this binder using the Validator.from(SerializablePredicate, ErrorMessageProvider) factory method.
Bean level validators are applied on the bean instance after the bean is updated. If the validators fail, the bean instance is reverted to its previous state.

Parameters:

predicate - the predicate performing validation, not null

errorMessageProvider - the provider to generate error messages, not null

Returns:

this binder, for chaining

See Also:

writeBean(Object), writeBeanIfValid(Object), withValidator(Validator), withValidator(SerializablePredicate, String)

validate
```
public BinderValidationStatus<BEAN> validate()
```
Validates the values of all bound fields and returns the validation status.
If all field level validators pass, and setBean(Object) has been used to bind to a bean, bean level validators are run for that bean. Bean level validators are ignored if there is no bound bean or if any field level validator fails.
Note: This method will attempt to temporarily apply all current changes to the bean and run full bean validation for it. The changes are reverted after bean validation.

Returns:

validation status for the binder

validate
```
protected BinderValidationStatus<BEAN> validate(boolean fireEvent)
```
Validates the values of all bound fields and returns the validation status. This method can skip firing the event, based on the given boolean.

Parameters:

fireEvent - true to fire validation status events; false to not

Returns:

validation status for the binder

isValid
```
public boolean isValid()
```
Runs all currently configured field level validators, as well as all bean level validators if a bean is currently set with setBean(Object), and returns whether any of the validators failed.
Note: Calling this method will not trigger status change events, unlike validate() and will not modify the UI. To also update error indicators on fields, use validate().isOk().
Note: This method will attempt to temporarily apply all current changes to the bean and run full bean validation for it. The changes are reverted after bean validation.

Returns:

whether this binder is in a valid state

Throws:

IllegalStateException - if bean level validators have been configured and no bean is currently set

See Also:

validate()

setStatusLabel
```
public void setStatusLabel(HasText statusLabel)
```
Sets the label to show the binder level validation errors not related to any specific field.
Only the one validation error message is shown in this label at a time.
This is a convenience method for setValidationStatusHandler(BinderValidationStatusHandler), which means that this method cannot be used after the handler has been set. Also the handler cannot be set after this label has been set.

Parameters:

statusLabel - the status label to set

See Also:

setValidationStatusHandler(BinderValidationStatusHandler), Binder.BindingBuilder.withStatusLabel(HasText)

getStatusLabel
```
public Optional<HasText> getStatusLabel()
```
Gets the status label or an empty optional if none has been set.

Returns:

the optional status label

See Also:

setStatusLabel(HasText)

setValidationStatusHandler
```
public void setValidationStatusHandler(BinderValidationStatusHandler<BEAN> statusHandler)
```
Sets the status handler to track form status changes.
Setting this handler will override the default behavior, which is to let fields show their validation status messages and show binder level validation errors or OK status in the label set with setStatusLabel(HasText).
This handler cannot be set after the status label has been set with setStatusLabel(HasText), or setStatusLabel(HasText) cannot be used after this handler has been set.

Parameters:

statusHandler - the status handler to set, not null

Throws:

NullPointerException - for null status handler

See Also:

setStatusLabel(HasText), Binder.BindingBuilder.withValidationStatusHandler(BindingValidationStatusHandler)

getValidationStatusHandler
```
public BinderValidationStatusHandler<BEAN> getValidationStatusHandler()
```
Gets the status handler of this form.
If none has been set with setValidationStatusHandler(BinderValidationStatusHandler), the default implementation is returned.

Returns:

the status handler used, never null

See Also:

setValidationStatusHandler(BinderValidationStatusHandler)

addStatusChangeListener
```
public Registration addStatusChangeListener(StatusChangeListener listener)
```
Adds status change listener to the binder.
The Binder status is changed whenever any of the following happens:
- if it's bound and any of its bound field or select has been changed
- writeBean(Object) or writeBeanIfValid(Object) is called
- readBean(Object) is called
- setBean(Object) is called
- removeBean() is called
- Binder.BindingBuilder.bind(ValueProvider, Setter) is called
- validate() or Binder.Binding.validate() is called
Parameters:

listener - status change listener to add, not null

Returns:

a registration for the listener

See Also:

readBean(Object), writeBean(Object), writeBeanIfValid(Object), setBean(Object), removeBean(), forField(HasValue), validate(), Binder.Binding.validate()

addListener
```
protected <T> Registration addListener(Class<T> eventType,
                                       SerializableConsumer<T> method)
```
Adds a listener to the binder.

Type Parameters:

T - the event type

Parameters:

eventType - the type of the event

method - the consumer method of the listener

Returns:

a registration for the listener

addValueChangeListener
```
public Registration addValueChangeListener(HasValue.ValueChangeListener<? super HasValue.ValueChangeEvent<?>> listener)
```
Adds field value change listener to all the fields in the binder.
Added listener is notified every time whenever any bound field value is changed, i.e. the UI component value was changed, passed all the conversions and validations then propagated to the bound bean field. The same functionality can be achieved by adding a HasValue.ValueChangeListener to all fields in the Binder.
The listener is added to all fields regardless of whether the method is invoked before or after field is bound.

Parameters:

listener - a field value change listener

Returns:

a registration for the listener

See Also:

HasValue.ValueChangeEvent, HasValue.ValueChangeListener

createBinding

protected <FIELDVALUE,TARGET> Binder.BindingBuilder<BEAN,TARGET> createBinding(HasValue<?,FIELDVALUE> field,
                                                                               Converter<FIELDVALUE,TARGET> converter,
                                                                               BindingValidationStatusHandler handler)

Creates a new binding with the given field.

Type Parameters:: FIELDVALUE - the value type of the field; TARGET - the target data type
Parameters:: field - the field to bind, not null; converter - the converter for converting between FIELDVALUE and TARGET types, not null; handler - the handler to notify of status changes, not null
Returns:: the new incomplete binding

doCreateBinding

protected <FIELDVALUE,TARGET> Binder.BindingBuilder<BEAN,TARGET> doCreateBinding(HasValue<?,FIELDVALUE> field,
                                                                                 Converter<FIELDVALUE,TARGET> converter,
                                                                                 BindingValidationStatusHandler handler)

handleError
```
protected void handleError(HasValue<?,?> field,
                           ValidationResult result)
```
Handles a validation error emitted when trying to write the value of the given field.

Parameters:

field - the field with the invalid value

result - the validation error result

clearError
```
protected void clearError(HasValue<?,?> field)
```
Clears the error condition of the given field, if any.

Parameters:

field - the field with an invalid value

handleValidationStatus
```
protected void handleValidationStatus(BindingValidationStatus<?> status)
```
Default BindingValidationStatusHandler functional method implementation.

Parameters:

status - the validation status

getBindings
```
protected Collection<Binder.BindingImpl<BEAN,?,?>> getBindings()
```
Returns the bindings for this binder.

Returns:

a list of the bindings

handleBinderValidationStatus
```
protected void handleBinderValidationStatus(BinderValidationStatus<BEAN> binderStatus)
```
The default binder level status handler.
Passes all field related results to the Binding status handlers. All other status changes are displayed in the status label, if one has been set with setStatusLabel(HasText).

Parameters:

binderStatus - status of validation results from binding and/or bean level validators

hasChanges

public boolean hasChanges()

Check whether any of the bound fields' have uncommitted changes since last explicit call to readBean(Object), removeBean(), writeBean(Object) or writeBeanIfValid(Object). Unsuccessful write operations will not affect this value.

Note that if you use setBean(Object) method, Binder tries to commit changes as soon as all validators have passed. Thus, when using this method with it seldom makes sense and almost always returns false. Return values for each case are compiled into the following table:

	After readBean, setBean or removeBean	After valid user changes	After invalid user changes	After successful writeBean or writeBeanIfValid	After unsuccessful writeBean or writeBeanIfValid
A bean is currently bound	`false`	`false`	`true`	`false`	no change
No bean is currently bound	`false`	`true`	`true`	`false`	no change

Returns:: whether any bound field's value has changed since last call to setBean, readBean, writeBean or writeBeanIfValid

setReadOnly
```
public void setReadOnly(boolean readOnly)
```
Sets the read only state to the given value for all currently bound fields.
This is just a shorthand for calling Binder.Binding.setReadOnly(boolean) for all current bindings. It means that bindings added after this method call won't be set read-only.

Parameters:

readOnly - true to set the bindings to read-only, false to set them to read-write

configureBinding

protected Binder.BindingBuilder<BEAN,?> configureBinding(Binder.BindingBuilder<BEAN,?> binding,
                                                         PropertyDefinition<BEAN,?> definition)

Configures the binding with the property definition definition before it's being bound.

Parameters:: binding - a binding to configure; definition - a property definition information
Returns:: the new configured binding

bindInstanceFields
```
public void bindInstanceFields(Object objectWithMemberFields)
```
Binds member fields found in the given object.
This method processes all (Java) member fields whose type extends HasValue and that can be mapped to a property id. Property name mapping is done based on the field name or on a @PropertyId annotation on the field. All non-null unbound fields for which a property name can be determined are bound to the property name using Binder.BindingBuilder.bind(String).
For example:
```
 public class MyForm extends VerticalLayout {
 private TextField firstName = new TextField("First name");
 @PropertyId("last")
 private TextField lastName = new TextField("Last name");

 MyForm myForm = new MyForm();
 ...
 binder.bindInstanceFields(myForm);
 
```
This binds the firstName TextField to a "firstName" property in the item, lastName TextField to a "last" property.
It's not always possible to bind a field to a property because their types are incompatible. E.g. custom converter is required to bind HasValue<String> and Integer property (that would be a case of "age" property). In such case IllegalStateException will be thrown unless the field has been configured manually before calling the bindInstanceFields(Object) method.
It's always possible to do custom binding for any field: the bindInstanceFields(Object) method doesn't override existing bindings.
Parameters:

objectWithMemberFields - The object that contains (Java) member fields to bind

Throws:

IllegalStateException - if there are incompatible HasValue<T> and property types

getBinding
```
public Optional<Binder.Binding<BEAN,?>> getBinding(String propertyName)
```
Gets the binding for a property name. Bindings are available by property name if bound using bind(HasValue, String), Binder.BindingBuilder.bind(String) or indirectly using bindInstanceFields(Object).

Parameters:

propertyName - the property name of the binding to get

Returns:

the binding corresponding to the property name, or an empty optional if there is no binding with that property name

getFields
```
public Stream<HasValue<?,?>> getFields()
```
Returns the fields this binder has been bound to.

Returns:

the fields with bindings

removeBinding
```
public void removeBinding(HasValue<?,?> field)
```
Finds and removes all Bindings for the given field.

Parameters:

field - the field to remove from bindings

removeBinding
```
public void removeBinding(Binder.Binding<BEAN,?> binding)
```
Removes the given Binding from this Binder.

Parameters:

binding - the binding to remove

removeBindingInternal
```
protected void removeBindingInternal(Binder.Binding<BEAN,?> binding)
```
Removes (internally) the Binding from the bound properties map (if present) and from the list of Bindings. Note that this DOES NOT remove the ValueChangeListener that the Binding might have registered with any HasValues or decouple the Binder from within the Binding. To do that, use Binder.Binding.unbind() This method should just be used for internal cleanup.

Parameters:

binding - The Binding to remove from the binding map

removeBinding
```
public void removeBinding(String propertyName)
```
Finds and removes the Binding for the given property name.

Parameters:

propertyName - the propertyName to remove from bindings

Class Binder<BEAN>

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Binder

Binder

Binder

Binder

Method Detail

withPropertySet

handleFieldValueChange

getBean

forField

forMemberField

bind

bind

setBean

removeBean

readBean

writeBean

writeBeanIfValid

restoreBeanState

getBeanState

withValidator

withValidator

withValidator

validate

validate

isValid

setStatusLabel

getStatusLabel

setValidationStatusHandler

getValidationStatusHandler

addStatusChangeListener

addListener

addValueChangeListener

createBinding

doCreateBinding

handleError

clearError

handleValidationStatus

getBindings

handleBinderValidationStatus

hasChanges

setReadOnly

configureBinding

bindInstanceFields

getBinding

getFields

removeBinding

removeBinding

removeBindingInternal

removeBinding