If I have a util class with static methods that will call Hibernate functions to accomplish basic data access. I am wondering if making the method synchronized
is the right approach to ensure thread-safety.
I want this to prevent access of info to the same DB instance. However, I'm now sure if the following code are preventing getObjectById
being called for all Classes when it is called by a particular class.
public class Utils {
public static synchronized Object getObjectById (Class objclass, Long id) {
// call hibernate class
Session session = new Configuration().configure().buildSessionFactory().openSession();
Object obj = session.load(objclass, id);
session.close();
return obj;
}
// other static methods
}
To address the question more generally...
Keep in mind that using synchronized on methods is really just shorthand (assume class is SomeClass):
synchronized static void foo() {
...
}
is the same as
static void foo() {
synchronized(SomeClass.class) {
...
}
}
and
synchronized void foo() {
...
}
is the same as
void foo() {
synchronized(this) {
...
}
}
You can use any object as the lock. If you want to lock subsets of static methods, you can
class SomeClass {
private static final Object LOCK_1 = new Object() {};
private static final Object LOCK_2 = new Object() {};
static void foo() {
synchronized(LOCK_1) {...}
}
static void fee() {
synchronized(LOCK_1) {...}
}
static void fie() {
synchronized(LOCK_2) {...}
}
static void fo() {
synchronized(LOCK_2) {...}
}
}
(for non-static methods, you would want to make the locks be non-static fields)