insatiate a class based on a string

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frank - 14 Jul 2005 14:48 GMT

Was wondering if there was a better way to insatiate a class based on
some string variable read from a properties file then an if-then-else?

String s = "class1";

if (s.equals("class1"))
{
myClass c1 = new class1();
}
else if (s.equals("class2"))
{
myClass c2 = new class2();
}
....

Thanks,

Frank

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Ingo R. Homann - 14 Jul 2005 14:51 GMT

Hi frank,

> Was wondering if there was a better way to insatiate a class based on
> some string variable read from a properties file then an if-then-else?
[quoted text clipped - 14 lines]
>
> Frank

Class.forName(s).newInstance();

Hth,
Ingo

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Daniel Dyer - 14 Jul 2005 14:55 GMT

> Was wondering if there was a better way to insatiate a class based on
> some string variable read from a properties file then an if-then-else?
[quoted text clipped - 10 lines]
> }
> ....

Use reflection. Take a look at the methods in the Class class
(http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Class.html),
particularly the forName and newInstance methods. You may also need the
getConstructor method and the java.lang.reflect.Constructor class if your
constructors have parameters.

Dan.

Signature

Daniel Dyer
http://www.dandyer.co.uk

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frank - 14 Jul 2005 16:13 GMT

Thanks!!!

>> Was wondering if there was a better way to insatiate a class based on
>> some string variable read from a properties file then an if-then-else?
[quoted text clipped - 18 lines]
>
> Dan.

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Roedy Green - 14 Jul 2005 22:25 GMT

>String s = "class1";
>
[quoted text clipped - 7 lines]
>}
>....

see http://mindprod.com/jgloss/classforname.html

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insatiate a class based on a string

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