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Index › Programming Questions & Help › Syntax Questions › Object exists

Emmanuel YaBB Newbies Offline Posts: 2	Object exists? Apr 16th, 2010, 5:28pm   Hey folks I can't find a reference to a method that checks if an object has been instantiated. Something like ObjectReference.exist() that returns a boolean... is there such a thing? Thanks a bunch

NoahBuddy Ex Member	Re: Object exists? Reply #1 - Apr 16th, 2010, 11:38pm   An object that has not been assigned to a "new something()"will be equal to null. i.e. if (myOb == null) {  myOb = new Object(); }

Emmanuel YaBB Newbies Offline Posts: 2	Re: Object exists? Reply #2 - Apr 21st, 2010, 2:32am   Thanks Noah! Should've thought of that... ^^ On a related topic, how can I test for the exact object reference, e.g. Player myFriend = new Player (); myMethod(myFriend); void myMethod(Player friend) { if (friend == myFriend) {...} // how can I compare two object references? }

PhiLho  YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: Object exists? Reply #3 - Apr 21st, 2010, 4:52am   The method you show is OK. == precisely compare object references, that's why in general it shouldn't be used to compare Strings... two identical strings of different origin (constant in code vs. file vs. loaded from net vs. build by concatenation, etc.) will have different references.

Bejoscha Full Member Offline Posts: 120	Re: Object exists? Reply #4 - Apr 21st, 2010, 9:35am   Ah! Thanks. Howshould one compare strings then?

PhiLho  YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: Object exists? Reply #5 - Apr 21st, 2010, 10:03am   string1.equals(string2) That's the generic method to compare object by content instead of by reference. You might need to override equals() for your own classes.