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Re: How to cancel the creation of an instance
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Posted: May 3, 2004 4:29 AM
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A Constructor should (can?) never return null.
If you really need to do it using a constructor, throw an exception, if the argument is null.
Class MyClass {
private MyClass (Object myParameter) throws ArgumentIsNullException {
if (myParameter == null)
throw new ArgumentIsNullException(...);
}
class ArgumentIsNullException extends Exception {
...
}
}
Otherwise I would recommend this way to do it:
Class MyClass {
/** No Instance can be created directly
*/
private MyClass (Object myParameter) {
}
/** This method does the trick. It returns null if a null value was passed as argument.
*/
public static MyClass createInstanceOfMyClass (Object myParameter) {
return myParameter == null? null : new MyClass(myParameter);
}
}
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