arraylist - Use Java HashMap multiple Type -

i'm using hashmap in-memory cache. basically, have:

private static final map<string, object> lookup = new hashmap<string, object>();      public static object get(cachehelper key) {         return lookup.get(key.getid());     }      public static void store(cachehelper key, object value) {         lookup.put(key.getid(), value);     } 

that's fine. every object "get" map, have cast, ugly. want put arraylist , many other different things it.

does know other solution typesafe ?

(for sure, can create every type getter , setter, solution ?

so, there better way create in-memory cache or have idea how wrap hashmap more safe ?

one solution problem make cachehelper type generic, cachehelper<t>. create wrapper map:

class mycache {   private final map<cachehelper<?>, object> backingmap = new hashmap<>();   public <t> void put(cachehelper<t> key, t value) {     backingmap.put(key, value);   }   @suppresswarnings("unchecked")   // long entries put in via put, cast safe   public <t> t get(cachehelper<t> key) {     return (t) backingmap.get(key);   } } 

the java compiler uses approach internally; see e.g. here. don't have pass around explicit class objects, have know type actually associated each key, should in well-behaved applications.