Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/updatables/ConvertingSet.java
Object converted = func.calculate(next);
			if (converted != null) {
				result.add(converted);
			}
		}
    	
    	return result;
    }
    protected void firstListenerAdded() {
        this.func.addChangeListener(inputListener);
        this.input.addChangeListener(inputListener);
        converter = new InverseMapping();
        
        addMappings(input.toCollection());
    	
    	super.firstListenerAdded();
    }
    
    protected void lastListenerRemoved() {
    	this.func.removeChangeListener(inputListener);
    	this.func.removeChangeListener(inputListener);
    	if (converter != null) {
    		converter.dispose();
    		converter = null;
    	}
    	super.lastListenerRemoved();
    }
}