smartCompare function for Java beans

smartCompare.java

    @SuppressWarnings({ "unchecked", "rawtypes" })
    private int smartCompare(final Object o1, final Object o2, String field, final Class comparable) {
        try {
            if (o1 == o2) {
                return 0;
            } else if (o1 != null && o2 == null) {
                return -1;
            } else if (o1 == null && o2 != null) {
                return 1;
            }
            
            Field f1 = o1.getClass().getField(field);
            f1.setAccessible(true);
            Field f2 = o2.getClass().getField(field);
            f2.setAccessible(true);
            
            if (f1.get(o1) == f2.get(o2)) {
                return 0;
            } else if (f1.get(o1) != null && f2.get(o2) == null) {
                return -1;
            } else if (f1.get(o1) == null && f2.get(o2) != null) {
                return 1;
            }
            
            // If the two provided objects are Comparable then we can directly compare them.
            if(null == comparable && f1.get(o1) instanceof Comparable && f2.get(o2) instanceof Comparable) {
                return ((Comparable) f1.get(o1)).compareTo(f2.get(o2)); 
            } else {
                // If a Comparable is provided, we use it.
                if(Comparable.class.isAssignableFrom(comparable)) {
                    Constructor<?> ctor1 = comparable.getConstructor(o1.getClass());
                    Comparable c1 = (Comparable) ctor1.newInstance(f1.get(o1));
                    Constructor<?> ctor2 = comparable.getConstructor(o2.getClass());
                    Comparable c2 = (Comparable) ctor2.newInstance(f2.get(o2));
                    return c1.compareTo(c2);
                } else {
                    throw new Exception(comparable.getName() + " does not implement Comparable");
                }                    
            }
            
        } catch (Exception e) {
            NotificationHelper.error("Technical error : " + e.getMessage());
            return 0;
        }
    }