Bug 126839 [DataBinding] IObservable refactoring
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/provisional/databinding/converterfunctions/ConvertObject2String.java
/* (non-Javadoc)
	 * @see org.eclipse.jface.binding.converter.IConverter#convert(java.lang.Object)
	 */
	public Object convert(Object source) {
        if (source == null) {
			return ""; 
		}
        
        IConversionFunction converter = ConversionFunctionRegistry.get(source.getClass(), String.class);
        if (converter != null) {
            return converter.convert(source);
        }
        
		throw new IllegalArgumentException("Unable to find a converter for " + source.getClass().getName() + " to String"); 
	}
}