Dirty check

spgmx · **Joined:** Sat Apr 07, 2007 4:42 pm **Posts:** 24

Hi,

how determines hibernate that an entity is dirty?
hashCode? equals? Comparing field values oder getter returns?

Thanx.

cbredesen · **Posted:** Fri May 18, 2007 3:26 pm

There's a snapshot copy in Session to compare against.

-Chris

spgmx · **Joined:** Sat Apr 07, 2007 4:42 pm **Posts:** 24

Yes, but how is it compared? Field by field, getter by getter, equals, hashcode..?

My problem is that my entity gets not updated although I changed a field value like this:

@Transient private String a;
private String b;

void setA(String a) {
this.a = a;
this.b = computeB(a);
}

Thus it seems that if b is not changed by setter setB(), dirty is not true.

max · **Posted:** Sun May 20, 2007 2:47 am

where is your @Id annotation placed?

spgmx · **Joined:** Sat Apr 07, 2007 4:42 pm **Posts:** 24

In the same class:

Code:

@Id
@GeneratedValue(strategy=GenerationType.AUTO) @SuppressWarnings(value={"unused"}) 
private int id;

cbredesen · **Posted:** Mon May 21, 2007 9:26 am

Properties are accessed however you specify they should be accessed. In JPA, the position of @Id determines this. If you put that annotation on a field, then field-access is used. If it's on a getter, property access is used.

-Chris

spgmx · **Joined:** Sat Apr 07, 2007 4:42 pm **Posts:** 24

Thanx.

But this keeps my question still open:

Why does hibernate not check that my entity is dirty and how is this check done in general?

cbredesen · **Posted:** Mon May 21, 2007 10:52 am

Follow the directions when posting and you'll get much better help.

http://www.hibernate.org/ForumMailingli ... AskForHelp

Quote:

When posting

* Give as much information as possible. Don't ignore the bullet points in the text field, fill out the required information. Yes, everything is needed in almost all cases.

max · **Posted:** Mon May 21, 2007 11:36 am

is your entity actually associated with a persistence context ?

with respect to dirtychecking then the general explanation is above...it takes a snapshot and then do a comparison when needed.

details can be seen in the code...look for Type.isEquals(x,y) method and friends.