Bug 147530 [DataBinding] Provide event objects for change listeners
Before data binding goes 1.0 it would be wise to provide EventObjects for the following listeners to ensure that the API doesn't preclude future expansion of the values supplied to listeners. Interfaces that would be affected: * IValueChangeListener * IValueChangingListener * IListChangeListener * ISetChangeListener * IMappingChangeListener
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/observable/map/BidirectionalMap.java
if (elementOrSet == null) {
			valueToElements.put(value, key);
			return;
		}
		if (!(elementOrSet instanceof Set)) {
			elementOrSet = new HashSet(Collections.singleton(elementOrSet));
			valueToElements.put(value, elementOrSet);
		}
		Set set = (Set) elementOrSet;
		set.add(key);
	}
	/**
	 * @param functionValue
	 * @param element
	 * @param b
	 */
	private void removeMapping(Object functionValue, Object element) {
		Object elementOrSet = valueToElements.get(functionValue);
		if (elementOrSet instanceof Set) {
			Set set = (Set) elementOrSet;
			set.remove(element);
			if (set.size() == 0) {
				valueToElements.remove(functionValue);
			}
		} else {
			valueToElements.remove(functionValue);
		}
	}
}