HasValue (GWT Javadoc)

Type Parameters:

T - the type of value

All Superinterfaces:

HasHandlers, HasValueChangeHandlers<T>, TakesValue<T>

All Known Subinterfaces:

HasConstrainedValue<T>

All Known Implementing Classes:

CellWidget, CheckBox, DateBox, DatePicker, DoubleBox, IntegerBox, LongBox, PasswordTextBox, RadioButton, SimpleCheckBox, SimpleRadioButton, SuggestBox, TextArea, TextBox, TextBoxBase, ToggleButton, ValueBox, ValueBoxBase, ValueListBox, ValuePicker
```
public interface HasValue<T>
extends TakesValue<T>, HasValueChangeHandlers<T>
```
Extends TakesValue to allow the value to be pulled back out, and to throw ValueChangeEvent events.
An object that implements this interface should be a user input widget, where the user and programmer can both set and get the object's value. It is intended to provide a unified interface to widgets with "atomic" values, like Strings and Dates.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`T`	`getValue()`	Gets this object's value.
`void`	`setValue(T value)`	Sets this object's value without firing any events.
`void`	`setValue(T value, boolean fireEvents)`	Sets this object's value.

Methods inherited from interface com.google.gwt.event.shared.HasHandlers
fireEvent

Methods inherited from interface com.google.gwt.event.logical.shared.HasValueChangeHandlers
addValueChangeHandler

- Method Detail
  - getValue
```
T getValue()
```
    Gets this object's value.
    
    Specified by:
    
    getValue in interface TakesValue<T>
    
    Returns:
    
    the object's value
    
    See Also:
    
    TakesValue.setValue(V)
  - setValue
```
void setValue(T value)
```
    Sets this object's value without firing any events. This should be identical to calling setValue(value, false).
    It is acceptable to fail assertions or throw (documented) unchecked exceptions in response to bad values.
    Widgets must accept null as a valid value. By convention, setting a widget to null clears value, calling getValue() on a cleared widget returns null. Widgets that can not be cleared (e.g. CheckBox) must find another valid meaning for null input.
    
    Specified by:
    
    setValue in interface TakesValue<T>
    
    Parameters:
    
    value - the object's new value
    
    See Also:
    
    TakesValue.getValue()
  - setValue
```
void setValue(T value,
              boolean fireEvents)
```
    Sets this object's value. Fires ValueChangeEvent when fireEvents is true and the new value does not equal the existing value.
    It is acceptable to fail assertions or throw (documented) unchecked exceptions in response to bad values.
    
    Parameters:
    
    value - the object's new value
    
    fireEvents - fire events if true and value is new