如何判断当前tx（Hibernate）中是否删除了Grails / GORM域实例？

Question

I am looking for a "isDeleted()" test for Grails (GORM) instances:

Project p = ... get persistent entity from somewhere ...
p.delete() // done in some nested logic
... sometime later in the code prior to commit of the tx ...
if (!p.isDeleted()) ... do some more stuff ...

In my app the logic that may delete p is elsewhere and passing a flag back or something would be a pain.

Answer 1

You need to get to the Hibernate session and persistence context:

import org.hibernate.engine.Status

boolean deleted = Project.withSession { session ->
   session.persistenceContext.getEntry(p).status == Status.DELETED
}

Answer 2

You could use GORM events to automatically set a property within the object once it has been deleted, eg

class Project{
   String name
   Boolean isDeleted = false
   static transients = [ "isDeleted" ]

  def afterDelete() { 
   isDeleted = true
  }
}

If for some reason you don't want to modify the domain classes, you could just use the exists method:

if (Project.exists(p.id)) {
  // do something....
}

Answer 3

my thoughts:

Project p = ... 
def id = p.id
p.delete(flush:true)
...
if (p.read(id)) //... do some more stuff ...