Many thanks Scott.
I'm a firestarter, twisted firestarter
> -----Message d'origine-----
> De : [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]De la part de
> Scott M Stark
> Envoyé : mardi 10 juillet 2001 20:32
> À : [EMAIL PROTECTED]
> Objet : [JBoss-dev] Fool proof? I think not.
>
>
> // TestPK.java
> class AccountPK implements java.io.Serializable
> {
> private int _hashCode = Integer.MIN_VALUE;
> public java.lang.String id;
>
> public AccountPK(java.lang.String id)
> {
> this.id = id;
> }
> public int hashCode()
> {
> if (_hashCode == Integer.MIN_VALUE)
> {
> _hashCode += this.id.hashCode();
> }
> return _hashCode;
> }
> public boolean equals(Object obj)
> {
> AccountPK pk = (AccountPK)obj;
> boolean eq = true;
> eq = eq && this.id.equals(pk.id);
> return eq;
> }
> }
>
> public class TestPK
> {
> public static void main (String args[])
> {
> AccountPK key1 = new AccountPK("key1");
> AccountPK key2 = new AccountPK("key1");
> CacheKey key3 = new CacheKey(key1);
> CacheKey key4 = new CacheKey(key2);
> if( key3.hashCode() != key4.hashCode() )
> System.out.println("key3, key4 hashCode test failed");
> if( key3.equals(key4) == false )
> System.out.println("key3, key4 equals test failed");
>
> AccountPK key11 = new AccountPK("key1");
> AccountPK key21 = new AccountPK("key1");
> key21.hashCode(); // Cause key21._hashCode value to update
> CacheKey key31 = new CacheKey(key11);
> CacheKey key41 = new CacheKey(key21);
> if( key31.hashCode() != key41.hashCode() )
> System.out.println("key31, key41 hashCode test failed");
> if( key31.equals(key41) == false )
> System.out.println("key31, key41 equals test failed");
> }
>
> }
>
> Produces:
>
> key31, key41 hashCode test failed
> key31, key41 equals test failed
>
> Why? Because Serialization includes the private state of the
> object. This is
> a perfectly valid PK which is not handled correctly by CacheKey. If the
> _hashCode value is marked as transient all works. The assumption being
> made by CacheKey is that the only ivars in the PK are its fields
> that define
> its identity.
>
>
>
>
> _______________________________________________
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> [EMAIL PROTECTED]
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>
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