Cast from Object to int?

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gaztedo - 20 Dec 2007 11:43 GMT

Hi there!

I'm developing a method which receives two Object parameters, and I need
to cast one of them to int. How can I do it?

public method(Object a, Object b){
this.b = (int)b; // doesn't work!
this.a = a;
}

Thanks in advance!

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Thomas Kellerer - 20 Dec 2007 11:48 GMT

gaztedo, 20.12.2007 12:43:

> Hi there!
>
[quoted text clipped - 5 lines]
> this.a = a;
> }

I guess the fact that your method declaration is invalid syntax is a
typing error in the email.

You cannot cast an Object to an int. If b is e.g. a Number object (e.g.
Integer or Long) you can do the following:

this.b = ((Number)b).intValue()

Btw: why don't you simple define your method as
public void method(Object o, int value)

Thomas

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gaztedo - 20 Dec 2007 12:29 GMT

> You cannot cast an Object to an int. If b is e.g. a Number object (e.g.
> Integer or Long) you can do the following:
>
> this.b = ((Number)b).intValue()

Thanks! It worked nice!

> Btw: why don't you simple define your method as
> public void method(Object o, int value)

I cannot do it... it's a long story ;)

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Andrew Thompson - 20 Dec 2007 14:16 GMT

...

>> Btw: why don't you simple define your method as
>> public void method(Object o, int value)
>
>I cannot do it... it's a long story ;)

Fortunately this is a big discussion forum, and
a lot of people enjoy a long story.

Signature

Andrew Thompson
http://www.physci.org/

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gaztedo - 20 Dec 2007 21:26 GMT

>> I cannot do it... it's a long story ;)
>
> Fortunately this is a big discussion forum, and
> a lot of people enjoy a long story.

Well, not such a huge story. I'm developing a parser using Yacc, and it
requires to develop some constructors (before I said methods, sorry)
using Object as a type.

So that was the reason I had to use Object and I couldn't use Integer.

BTW I still have a lot of different errors :S

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Martin Gregorie - 21 Dec 2007 17:13 GMT

>>> I cannot do it... it's a long story ;)
>>
[quoted text clipped - 4 lines]
> requires to develop some constructors (before I said methods, sorry)
> using Object as a type.

Why use yacc with Java?

Have you looked at some of the Java equivalents, such as Coco/R?
http://www.ssw.uni-linz.ac.at/Research/Projects/Coco/

Signature

martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

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Roedy Green - 20 Dec 2007 18:33 GMT

>I'm developing a method which receives two Object parameters, and I need
>to cast one of them to int. How can I do it?

You can't because int is not an Object. You could cast it perhaps to
Integer or to whatever the object actually was. From there you can
convert, but not cast, it to int.

See http://mindprod.com/jgloss/conversion.html

To find out what kind of animal you have:

System.out.println( obj.getClass().toString() );

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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