com.vaadin.flow.data.binder

Class ReadOnlyHasValue<V>

java.lang.Object

com.vaadin.flow.data.binder.ReadOnlyHasValue<V>

Type Parameters:

V - the value type

All Implemented Interfaces:

HasValue<HasValue.ValueChangeEvent<V>,V>, Serializable

public class ReadOnlyHasValue<V>
extends Object
implements HasValue<HasValue.ValueChangeEvent<V>,V>, Serializable

Generic HasValue to use any type of component with Vaadin data binding.

Example:

 Label label = new Label();
 ReadOnlyHasValue<String> hasValue = new ReadOnlyHasValue<>(label::setText);
 binder.forField(hasValue).bind(SomeBean::getName, null);
 

Since:

1.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.flow.component.HasValue

HasValue.ValueChangeEvent<V>, HasValue.ValueChangeListener<E extends HasValue.ValueChangeEvent<?>>

Constructor Summary

Constructors

Constructor and Description
ReadOnlyHasValue(SerializableConsumer<V> valueProcessor) Creates new ReadOnlyHasValue with null as an empty value.
ReadOnlyHasValue(SerializableConsumer<V> valueProcessor, V emptyValue) Creates new ReadOnlyHasValue

Method Summary

Modifier and Type	Method and Description
Registration	addValueChangeListener(HasValue.ValueChangeListener<? super HasValue.ValueChangeEvent<V>> listener) Adds a value change listener.
V	getEmptyValue() Returns the value that represents an empty value.
V	getValue() Returns the current value of this object.
boolean	isReadOnly() Returns whether this HasValue is in read-only mode or not.
boolean	isRequiredIndicatorVisible() Checks whether the required indicator is visible.
void	setReadOnly(boolean readOnly) Sets the read-only mode of this HasValue to given mode.
void	setRequiredIndicatorVisible(boolean requiredIndicatorVisible) Sets the required indicator visible or not.
void	setValue(V value) Sets the value of this object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.vaadin.flow.component.HasValue

clear, getOptionalValue, isEmpty

Constructor Detail

ReadOnlyHasValue

public ReadOnlyHasValue(SerializableConsumer<V> valueProcessor,
                        V emptyValue)

Creates new ReadOnlyHasValue

Parameters:

valueProcessor - the value valueProcessor, e.g. a setter for displaying the value in a component

emptyValue - the value to be used as empty, null by default

ReadOnlyHasValue

public ReadOnlyHasValue(SerializableConsumer<V> valueProcessor)

Creates new ReadOnlyHasValue with null as an empty value.

Parameters:

valueProcessor - the value valueProcessor, e.g. a setter for displaying the value in a component

Method Detail

setValue

public void setValue(V value)

Description copied from interface: HasValue

Sets the value of this object. If the new value is not equal to getValue(), fires a value change event. May throw IllegalArgumentException if the value is not acceptable.

Implementation note: the implementing class should document whether null values are accepted or not, and override HasValue.getEmptyValue() if the empty value is not null.

Specified by:

setValue in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Parameters:

value - the new value

getValue

public V getValue()

Description copied from interface: HasValue

Returns the current value of this object.

Implementation note: the implementing class should document whether null values may be returned or not, and override HasValue.getEmptyValue() if the empty value is not null.

Specified by:

getValue in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Returns:

the current value

addValueChangeListener

public Registration addValueChangeListener(HasValue.ValueChangeListener<? super HasValue.ValueChangeEvent<V>> listener)

Description copied from interface: HasValue

Adds a value change listener. The listener is called when the value of this HasValue is changed either by the user or programmatically.

Specified by:

addValueChangeListener in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Parameters:

listener - the value change listener, not null

Returns:

a registration for the listener

isRequiredIndicatorVisible

public boolean isRequiredIndicatorVisible()

Description copied from interface: HasValue

Checks whether the required indicator is visible.

Specified by:

isRequiredIndicatorVisible in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Returns:

true if visible, false if not

setRequiredIndicatorVisible

public void setRequiredIndicatorVisible(boolean requiredIndicatorVisible)

Description copied from interface: HasValue

Sets the required indicator visible or not.

If set visible, it is visually indicated in the user interface.

The method is intended to be used with Binder which does server-side validation. In case HTML element has its own (client-side) validation it should be disabled when setRequiredIndicatorVisible(true) is called and re-enabled back on setRequiredIndicatorVisible(false). It's responsibility of each component implementation to follow the contract so that the method call doesn't do anything else than show/hide the "required" indication. Usually components provide their own setRequired method which should be called in case the client-side validation is required.

Specified by:

setRequiredIndicatorVisible in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Parameters:

requiredIndicatorVisible - true to make the required indicator visible, false if not

setReadOnly

public void setReadOnly(boolean readOnly)

Description copied from interface: HasValue

Sets the read-only mode of this HasValue to given mode. The user can't change the value when in read-only mode.

A HasValue with a visual component in read-only mode typically looks visually different to signal to the user that the value cannot be edited.

Specified by:

setReadOnly in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Parameters:

readOnly - a boolean value specifying whether the component is put read-only mode or not

isReadOnly

public boolean isReadOnly()

Description copied from interface: HasValue

Returns whether this HasValue is in read-only mode or not.

Specified by:

isReadOnly in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Returns:

false if the user can modify the value, true if not.

getEmptyValue

public V getEmptyValue()

Description copied from interface: HasValue

Returns the value that represents an empty value.

By default HasValue is expected to support null as empty values. Specific implementations might not support this.

Specified by:

getEmptyValue in interface HasValue<HasValue.ValueChangeEvent<V>,V>

Returns:

empty value