Re: Documentation suggestion

Karl,

If you write up a full doc we can put it on the site. No problem.

See you, Klaus.

On Mon, Jan 11, 2010 at 6:32 AM, Karl Wettin <[email protected]> wrote:
> Even though it's not that hard to figure out by one self, I think it
> might help some users if at least one of the example projects (or if
> the Wiki at some smart place) as built to show the pitfalls of
> java.io.Serializable and explained how one can achieve backwards
> compatibillity using local versioning of domain objects with
> Externalizable. It makes life so much easier for people such as me
> that have an evolving domain class model.
>
> Dry-coded example:
>
> public abstract class LegalPerson implements Serializable,
> Externalizable {
>
>   private static final long serialVersionUID = 1l; // never change this
>
>   private String id;
>   private String name;
>
>   @Override
>   public void writeExternal(ObjectOutput objectOutput) throws
> IOException {
>     objectOutput.writeInt(1); // version
>     objectOutput.writeObject(id);
>     objectOutput.writeObject(name);
>   }
>
>   @Override
>   public void readExternal(ObjectInput objectInput) throws
> IOException, ClassNotFoundException {
>     int version = objectInput.readInt();
>     if (version == 1) {
>       id = (String)objectInput.readObject();
>       name = (String)objectInput.readObject();
>     } else {
>       throw new IOException("Unknown local version: " + version);
>     }
>   }
> }
>
> public abstract class Organization extends LegalPerson {
>
>   private static final long serialVersionUID = 1l; // never change this
>
>   private String organizationNumber;
>
>   @Override
>   public void writeExternal(ObjectOutput objectOutput) throws
> IOException {
>     super.writeExternal(objectOutput);
>
>     objectOutput.writeInt(1); // version
>     objectOutput.writeObject(organizationNumber);
>   }
>
>   @Override
>   public void readExternal(ObjectInput objectInput) throws
> IOException, ClassNotFoundException {
>     super.readExternal(objectInput);
>
>     int version = objectInput.readInt();
>     if (version == 1) {
>       organizationNumber = (String)objectInput.readObject();
>     } else {
>       throw new IOException("Unknown local version: " + version);
>     }
>   }
> }
>
>
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