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Article View: borland.public.jbuilder.java.language
Article #8134

Re: How to test if object has an exact type

#8134
From: Torsten Welches
Date: Fri, 20 Apr 2001 13:37
33 lines
2175 bytes
David,

try that:
String s = "TEST";
boolean isFalse = s.getClass().equals(Object.class);
boolean isTrue = s.getClass().equals(String.class);

Torsten

"David Crocker" <dcrocker@imsltd.com> wrote:
>I have a requirement to distinguish at run-time whether a variable X is
>exactly of some type T as opposed to being of some type derived from T. I
>have to assume that T might be extended by an ignorant third party, so
>defining a virtual function in T and then overridding it in all descendents
>of T is not an option.
>
>What is the best way of doing this? I know I can use getClass() to get the
>Class object of the run-time type of X, but is there an efficient way to get
>the Class object that corresponds to T? So far the best I can come up with
>is to declare within class T the following:
>
>   static const Class myClass = Class.forName("T");
>
>then I can express the test as "X.getClass() == T.myClass".
>
>Is there a better way? Does Java provide any other way of obtaining the
>Class object for a given type? Any other ideas or advice will be
>appreciated.
>
>Dave Crocker, Escher Technologies Ltd.
>
>
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Subject: Re: How to test if object has an exact type
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