In Objective-C, what is the equivalent of Java's "instanceof" keyword?
Objective CTypesCastingEqualityDowncastObjective C Problem Overview
I would like to check whether an object (e.g. someObject) is assignable (cast-able) to a variable of another type (e.g. SpecifiedType). In Java, I can write:
someObject instanceof SpecifiedType
A related question is finding whether the runtime type of an object is equal to a another type. In Java, I can write:
someObject.getClass().equals(SpecifiedType.class)
How can this be done in Objective-C?
Objective C Solutions
Solution 1 - Objective C
Try [myObject class] for returning the class of an object.
You can make exact comparisons with:
if ([myObject class] == [MyClass class])
but not by using directly MyClass identifier.
Similarily, you can find if the object is of a subclass of your class with:
if ([myObject isKindOfClass:[AnObject class]])
as suggested by Jon Skeet and zoul.
Solution 2 - Objective C
From Wikipedia:
> In Objective-C, for example, both the
> generic Object and NSObject (in
> Cocoa/OpenStep) provide the method
> isMemberOfClass: which returns true if
> the argument to the method is an
> instance of the specified class. The
> method isKindOfClass: analogously
> returns true if the argument inherits
> from the specified class.
isKindOfClass: would be closest to instanceof, by the sounds of it.
Solution 3 - Objective C
See the isKindOfClass: method in the NSObject documentation. (The usual word of warning for such question is that checking the object class is often a sign of doing something wrong.)