Keith, If I have time, I'll try to whip up something.
-----Original Message----- From: Keith Visco [mailto:[EMAIL PROTECTED]] Sent: Tuesday, April 02, 2002 1:41 PM To: [EMAIL PROTECTED] Subject: Re: [castor-dev] problems serializing type-safe enumerations Hi Erik, I read about this issue in a recent JDC Tech Tips (Java Developer Connection) newsletter from Sun. I was planning on trying to make the serialization work properly, however haven't had to much time to look into it. I was hoping this issue wouldn't come up so quickly, since I just read about the problem in the February 5th issue of the JDC Tech Tips. We'll code up a solution for people using "-type j2" option. Hopefully in the meantime you don't mind modifying your enumerations until we have a chance to do it. Or if you have a little time and want to try to fix the problem in Castor itself that would be great for all of us. Thanks, --Keith [EMAIL PROTECTED] wrote: > > Greetings, all. Thanks for such a great product. > > We are using the SourceGenerator to generate java classes based on a > schema. We are using the feature > that generates a Java type-safe enum pattern from an XML Schema > enumeration. > When we serialize those type-safe enum objects (over RMI), we are > running into problems described in this article > (http://www.javaworld.com/javaworld/javatips/jw-javatip122.html). > > In short, the == and .equals() don't work after a type-safe enumeration > object has been serialized. > Instead, one object never equals another object. > > Do you have any suggestions? One option would be to code generate a > readResolve() method as described in the article. > > Thanks again, > > Erik Ostermueller > [EMAIL PROTECTED] > ################################################### > > The following is an exerpt from this article: > > At a minimum, we have to add a readResolve() method and an instance > field to use as the real instance ID: > public final class Enum implements java.io.Serializable > { > public static final Enum TRUE = new Enum (true); > public static final Enum FALSE = new Enum (false); > > public String toString () > { > return String.valueOf (m_value).toUpperCase (); > } > > private Enum (boolean value) > { > m_value = value; > } > > private Object readResolve () throws java.io.ObjectStreamException > { > return (m_value ? TRUE : FALSE); > } > > private boolean m_value; > > } // end of class > Here, in the readResolve() method, I check the value ID of the instance > just created and replace the deserialized instance with one of the > static objects. > Unfortunately, many programmers today are unaware they must implement > readResolve() to perform instance substitution during serialization > (this feature was not available before Java 2 either). If we don't do > this, however, we won't get any compiler or runtime errors -- the > reference comparison will simply fail each time we compare an Enum value > against a deserialized Enum instance. Depending on the enumeration's > size, the amount of work necessary to have a correct and serializable > typesafe class may be too much compared to the good old "typeunsafe" > pattern (the standard practice of defining simple-minded sets of > constants referred to earlier), which lacks this issue. > > ----------------------------------------------------------- > If you wish to unsubscribe from this mailing, send mail to > [EMAIL PROTECTED] with a subject of: > unsubscribe castor-dev ----------------------------------------------------------- If you wish to unsubscribe from this mailing, send mail to [EMAIL PROTECTED] with a subject of: unsubscribe castor-dev ----------------------------------------------------------- If you wish to unsubscribe from this mailing, send mail to [EMAIL PROTECTED] with a subject of: unsubscribe castor-dev
