instanceof Operator

[Raghavender Ammagari]

Hi,

I have an object and a string that contains a name of the class...how do I check if that object is an instance of the class specified by that string....for example

Exception  exceptobject; 
String classname="java.lang.ArrayIndexOutOfBoundsException";
 . . .
 . . .
//got something into the exceptobject 
 . . .
 . . .
//now how do I check if exceptobject is an instance of the class represented by the string "classname"

//when i try to use instanceof operator....all that I can do is 

if(exceptobject instanceof ...........){

}

what should go into the blank above...please help me

[Stephan van Hulst]

I don't believe you can use the instanceof operator for this.

Instead, you can try the following:

Class.forName(classname).isInstance(exceptobject);

[Seetharaman Venkatasamy]

create String Class from fully qualified name of Exception. and use isInstance method of Class to verify wether the argument type can be convert/cast to the reference type. for example see below.

Exception  exceptobject = new Exception();   
String classname="java.lang.ArrayIndexOutOfBoundsException";			 
Class clazz = Class.forName(classname);
			 
System.out.println(clazz.isInstance(exceptobject));

from isInstance method Javadoc:

Determines if the specified <code>Object</code> is assignment-compatible
with the object represented by this <code>Class</code>. This method is
the dynamic equivalent of the Java language <code>instanceof</code>
operator. The method returns <code>true</code> if the specified
<code>Object</code> argument is non-null and can be cast to the
reference type represented by this <code>Class</code> object without
raising a <code>ClassCastException.</code> It returns <code>false</code>
otherwise.

[Seetharaman Venkatasamy]

Ah, Stephan beaten me here!

[Raghavender Ammagari]

thanks a lot guys...