Subscribe through JSON string

[ManKeer]

One of my clients tries to subscribe tm my adapter through a JSON string as the following:

1. if getItems method received {"name":"LStocks","pick":""}

DataProvider is LSTOCKS, since the pick is an empty string, the server should publish all market stocks to the market. [BROADCAST all market stocks]

2. if getItems method received {"name":"LStocks","pick":"item1#item2#item3"}

DataProvider is LSTOCKS, and the client should receives the updates for stocks named as: item1, item2 and item3 only [UNICAST]

my questions are:

Does this subscription format valid for Lightstreamer?
if YES, does it affect the subscription and unsubscription performance?
Does it cause any abnormal consequences or results?