Class DateAndTimeObservableValue

  • All Implemented Interfaces:
    IObservable, IObservableValue<Date>

    public class DateAndTimeObservableValue
    extends AbstractObservableValue<Date>
    An IObservableValue < Date > which supports scenarios where the date and time are presented as separate elements in the user interface. This class combines the year, month, and day portion of the date observable (an IObservableValue < Date >) and the hour, minute, second, and millisecond portion of the time observable (also an IObservableValue < Date >).

    This observable's value will be null whenever the date observable's value is null. Otherwise the value is the combination of the date portion of the date observable and the time portion of the time observable (a time observable value of null is treated the same as 0:00:00.000).

    When setting the value of this observable, setting a null value will set null on the date observable, and set a time of 0:00:00.000 on the time observable. When setting non-null values, the non-applicable fields of each observable are left intact. That is, the hour, minute, second and millisecond components of the date observable are preserved, and the year, month and day components of the time observable are preserved.

    The observables used for the date and time component may impose their own restrictions with regard to supported values. For example some observables do not allow a null value, because the underlying widget lacks support for a null value (example: DateTime).

    One use for this class is binding a date-and-time value to two separate user interface elements, one for editing date and one for editing time:

     DataBindingContext dbc = new DataBindingContext();
     IObservableValue beanValue = BeansObservables.observeValue(...);
     IObservableValue dateObservable = WidgetProperties.selection().observe(
                    dateWidget);
     IObservableValue timeObservable = WidgetProperties.selection().observe(
                    timeWidget);
     dbc.bindValue(new DateAndTimeObservableValue(dateObservable, timeObservable),
                    beanValue);
     
    A second use is editing only the date or time value of a date-and-time value. This can be accomplished by using a widget-specific observable for the editable value and a WritableValue as a container for the fixed value. The example below allows editing the date while preserving the time:
     DataBindingContext dbc = new DataBindingContext();
     IObservableValue beanValue = BeansObservables.observeValue(...);
     IObservableValue dateObservable = WidgetProperties.selection().observe(
                    dateWidget);
     IObservableValue timeObservable = new WritableValue(dateObservable.getRealm(),
                    beanValue.getValue(), Date.class);
     dbc.bindValue(new DateAndTimeObservableValue(dateObservable, timeObservable), beanValue);
    
     
    Since:
    1.2
    • Constructor Detail

      • DateAndTimeObservableValue

        public DateAndTimeObservableValue​(IObservableValue<Date> dateObservable,
                                          IObservableValue<Date> timeObservable)
        Constructs a DateAndTimeObservableValue with the specified constituent observables.
        Parameters:
        dateObservable - the observable used for the date component (year, month and day) of the constructed observable.
        timeObservable - the observable used for the time component (hour, minute, second and millisecond) of the constructed observable.
    • Method Detail

      • getValueType

        public Object getValueType()
        Description copied from interface: IObservableValue
        The value type of this observable value, or null if this observable value is untyped.
        Returns:
        the value type, or null
      • firstListenerAdded

        protected void firstListenerAdded()
      • lastListenerRemoved

        protected void lastListenerRemoved()
      • isStale

        public boolean isStale()
        Description copied from interface: IObservable
        Returns whether the state of this observable is stale and is expected to change soon. A non-stale observable that becomes stale will notify its stale listeners. A stale object that becomes non-stale does so by changing its state and notifying its change listeners, it does not notify its stale listeners about becoming non-stale. Clients that do not expect asynchronous changes may ignore staleness of observable objects.
        Specified by:
        isStale in interface IObservable
        Overrides:
        isStale in class AbstractObservableValue<Date>
        Returns:
        true if this observable's state is stale and will change soon.
      • dispose

        public void dispose()
        Description copied from interface: IObservable
        Disposes of this observable object, removing all listeners registered with this object, and all listeners this object might have registered on other objects.
        Specified by:
        dispose in interface IObservable
        Overrides:
        dispose in class AbstractObservable
      • addListener

        protected void addListener​(Object listenerType,
                                   IObservablesListener listener)
        Parameters:
        listenerType -
        listener -
      • removeListener

        protected void removeListener​(Object listenerType,
                                      IObservablesListener listener)
        Parameters:
        listenerType -
        listener -
      • hasListeners

        protected boolean hasListeners()
      • getRealm

        public Realm getRealm()
        Returns:
        Returns the realm.