@Override
public boolean writeReference(JSONSerializer serializer, Object object,
		int fieldFeatures) {

	SerialContext context = serializer.getContext();
	{

		if (context != null
				&& SerializerFeature.isEnabled(context.getFeatures(),
						fieldFeatures,
						SerializerFeature.DisableCircularReferenceDetect)) {
			return false;
		}
	}

	if (!serializer.containsReference(object)) {
		return false;
	}

	SerialContext parentCtx = context;
	while ((parentCtx = parentCtx.getParent()) != null) {
		Object parentObj = parentCtx.getObject();
		if (object.equals(parentObj)) {
			serializer.writeNull();
			return true;
		}
	}
	return false;
}
 

private void handle(JSONSerializer serializer, ObjectSerializer itemSerializer, SerialContext context,
		Object object, Object fieldName, Type elementType,  Object item) throws IOException {
	serializer.println();
	if (item != null) {
		itemSerializer = serializer.getObjectWriter(item.getClass());
		SerialContext itemContext = new SerialContext(context, object, fieldName, 0, 0);
		serializer.setContext(itemContext);
		itemSerializer.write(serializer, item, fieldName, elementType, 0);
	} 
	else {
		serializer.getWriter().writeNull();
	}
}
 

public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features) throws IOException {
    SerializeWriter out = serializer.getWriter();
    if (object == null) {
        if (out.isEnabled(SerializerFeature.WriteNullListAsEmpty)) {
            out.write("[]");
        } 
        else {
            out.writeNull();
        }
        return;
    }

    Type elementType = null;
    if (serializer.isEnabled(SerializerFeature.WriteClassName)) {
        if (fieldType instanceof ParameterizedType) {
            ParameterizedType param = (ParameterizedType) fieldType;
            elementType = param.getActualTypeArguments()[0];
        }
    }

    Collection<?> collection = (Collection<?>) object;

    SerialContext context = serializer.getContext();
    serializer.setContext(context, object, fieldName, 0);

    if (serializer.isEnabled(SerializerFeature.WriteClassName)) {
        if (HashSet.class == collection.getClass()) {
            out.append("Set");
        } 
        else if (TreeSet.class == collection.getClass()) {
            out.append("TreeSet");
        }
    }

    try {
        int i = 0;
        out.append('[');
        
        for (Object item : collection) {

            if (i++ != 0) {
                out.append(',');
            }

            if (item == null) {
                out.writeNull();
                continue;
            }

            Class<?> clazz = item.getClass();

            if (clazz == Integer.class) {
                out.writeInt(((Integer) item).intValue());
                continue;
            }

            if (clazz == Long.class) {
                out.writeLong(((Long) item).longValue());

                if (out.isEnabled(SerializerFeature.WriteClassName)) {
                    out.write('L');
                }
                continue;
            }

            ObjectSerializer itemSerializer = serializer.getObjectWriter(clazz);
            itemSerializer.write(serializer, item, i - 1, elementType, 0);
        }
        out.append(']');
    } 
    finally {
        serializer.setContext(context);
    }
}