Examples with BaseWidgetPropertyListener org.csstudio.display.builder.model.BaseWidgetPropertyListener used on opensource projects

Example 1 with BaseWidgetPropertyListener

use of org.csstudio.display.builder.model.BaseWidgetPropertyListener in project org.csstudio.display.builder by kasemir.

the class PropertyChangeHandler method firePropertyChange.

/**
 * Notify listeners of property change.
 *
 *  <p>New value usually matches <code>property.getValue()</code>,
 *  but in multi-threaded context value might already have changed
 *  _again_ by the time this executes.
 *
 *  <p>Suppresses notifications where old_value equals new_value,
 *  unless both values are null, treating that as a "notify anyway"
 *  case.
 *
 *  @param property Property that changed, or <code>null</code> for "many"
 *  @param old_value Original value
 *  @param new_value New value
 */
@SuppressWarnings("unchecked")
protected void firePropertyChange(final WidgetProperty<T> property, final T old_value, final T new_value) {
    // Does anybody care?
    final List<BaseWidgetPropertyListener> safe_copy = listeners;
    if (safe_copy == null)
        return;
    // Any change at all?
    if (new_value != null && old_value != null && new_value.equals(old_value))
        return;
    // If a property listener changes the property,
    // that triggers a recursive listener invocation.
    // Not necessarily a problem, but likely better avoided.
    final int recursion_level = recursions.incrementAndGet();
    if (recursion_level > 1)
        logger.log(Level.WARNING, "Recursive update of property " + property.getName() + ", " + recursion_level + " deep");
    // Notify listeners
    for (BaseWidgetPropertyListener listener : safe_copy) {
        try {
            if (listener instanceof WidgetPropertyListener)
                ((WidgetPropertyListener<T>) listener).propertyChanged(property, old_value, new_value);
            else
                ((UntypedWidgetPropertyListener) listener).propertyChanged(property, old_value, new_value);
        } catch (Throwable ex) {
            // Log error, then continue with next listener
            logger.log(Level.WARNING, "Property update error for " + property, ex);
        }
    }
    recursions.decrementAndGet();
}