Re: [newbe] casting at run time

"polilop" <>
Fri, 12 Jan 2007 08:13:06 +0100
Sorry for me being hasty, here is the real code

public interface J2EEVo {
 public abstract boolean isSuccess();
 public abstract void setSuccess(boolean success);
public class UsersVo implements J2EEVo
  private String USERNAME;
 private String FAMILYNAME;
 private boolean success;

... a class constructor and set get methods
public class ReportVo implements J2EEVo
  private String HEADER;
 private String FOOTER;
 private boolean success;

... add class constructor and set get methods

public class ResultsetToVo {

 public J2EEVo fillVo(J2EEVo uvo,ResultSet rs) throws SQLException
    if(uvo instanceof UsersVo) {
     uvo = (UsersVo)uvo;
    else if(uvo instanceof ReportVo )

To answer Tom Hawtin: I am aware of instanceof, but is there another way to
cast the uvo at run time, so that i don't have to add a new if (uvo
insanceof someVo), every time a write a new J2EEVo that needs to use
ResultsetToVo. Something like (just a thought):

uvo =(getUvoClassInstance(uvo))uvo

"Lew" <> wrote in message

polilop wrote:

class D

public doSomethingWithTypeA(A aClass)

/***So what i do is***/
if(B instanceof A)
cast A to B
if(C instanceof A)
cast A to C

B b=new B();
D d=new D();

Your code as posted will not compile.

Create a real example. Try it before you post it.

You cannot invoke the "instanceof" operator with a type as the left

The variable name "aClass" is misleading since the variable is not of type
Class but of type A. It is bad practice to embed type information in a
variable name.

- Lew

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