Re: ClassCastException in some browser, but not others (

Probably

--> IDBDatabase idb = Js.uncheckedCast(idbr.result);

would work too.

The point is is uncheckedCast is (AFAIU) considered dangerous.

There are two other casts that perform run-time checks but they have a 1) performance penalty and 2) some times throw exceptions not due to a bug but because the casting is invalid based on the type definitions GWT compiler knows about.

Here is the first type:
a) Java cast --> MyObject x = (MyObject) yourObject;
b) Js checked cast --> MyObject x = Js.cast(yourObject);
and of course
c) Js unchecked cast --> MyObject x = Js.uncheckedCast(yourObject);

I think (not sure) that a) and b) are the same at least on development mode. Not so sure what they are doing in production mode.

My 2 cents of limited understanding...

Vassilis



On 10/6/19 7:00 AM, Shawn Asamoto-Brown wrote:
> OK, this works --> IDBDatabase idb = Js.<IDBDatabase> uncheckedCast(idbr.result);
>
> @SuppressWarnings({ "unchecked" })
> public static void initIndexedDb(){
>
> IDBFactory idbf= IndexedDbGlobal.indexedDB;
> IDBOpenDBRequest idbr= idbf.open(INDEXEDDB_NAME);
>
> idbr.onsuccess= new OnsuccessFn() {
>
> @Override
> public Object onInvoke(elemental2.dom.Event p0) {
>
> // fails w java.lang.ClassCastException
> // IDBDatabase idb = (IDBDatabase) idbr.result;
> // IDBDatabase idb = Js.<IDBDatabase> cast(db);
>
> //this works
> IDBDatabase idb= Js.<IDBDatabase > uncheckedCast(idbr.result);
>
> DOMStringList dsl= idb.objectStoreNames;
>
> dsl.asList().forEach(s-> {
> Log.info("FOUND DB " + s);
> });
>
> return idbr.result;
> }
> };
>
> idbr.onerror= new OnerrorFn() {
>
> @Override
> public Object onInvoke(elemental2.dom.Event p0) {
> Log.error("OnerrorFn " + p0.type);
> return null;
> }
> };
> }
>
>
> On Sat, Oct 5, 2019 at 10:47 PM Shawn <shawn@koyuru.com <mailto:shawn@koyuru.com>> wrote:
>
> Meant to add that I am sure indexeddb is supported in all the browsers I am using.
>
> Here is the code again ... sorry about the previous formatting.
>
> IDBFactory idbf = IndexedDbGlobal./indexedDB/;
>
> IDBOpenDBRequest idbr = idbf.open(*/INDEXEDDB_NAME/*);
>
> idbr*.*onsuccess = new OnsuccessFn() {
>
>
> /@Override/
>
> public Object onInvoke(elemental2.dom.Event p0) {
>
>                                         //error is next
>
> idb = (IDBDatabase)idbr.result;
>
>
> DOMStringList dsl = idb.objectStoreNames;
>
>
> dsl.asList().forEach(s -> {
>
> Log./error/("FOUND DB " + s);
>
> });
>
> return idbr.result;
>
> }
>
> };
>
>
> On Chrome desktop, I find the indexeddb I created in handwritten js code.  I don't get why there is a ClassCastException in some browsers.  Is elemental2-indexeddb or gxt 2.9 (HEAD) not supported everywhere?
>
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