h2. Controller - Session Management

*WARNING: Play Session is NOT the J2EE session*
session and flash use cookies! 4KB limit/20 cookies max

*session.getId();*
Returns the session ID - in most cases: a must have!

*session.put(String key, String value);*
*session.get("user_flag");*
Values are limited to Strings, 4KB max

*flash.put(String key, String value);*
*flash.get(String key);*
Flash entries are discarded at end of next request

*Cache.set("key_" + id, product, "30mn");*
Set cache value to 30 minutes

*Cache.get("key_" + id, Product.class);*
Get cache value, may return null

*Cache.delete("key_" + id);*
Non blocking cache delete

*Cache.safeDelete("key_" + id);*
Blocking cache delete
