Java - Reentrant WriteLock on static methods

Question

How to use WriteLock on a static method? this is what I have got:

m_unitLock = new ReentrantReadWriteLock();
m_unitReadLock = m_unitLock.readLock();
m_unitWriteLock = m_unitLock.writeLock()

static List<unit> units = new ArrayList<Unit>();
...
public static addUnit(){
  m_unitWriteLock.lock(); // can not use this inside a static method
  units.add(unit);
  m_unitWriteLock.unlock();
}

Is it the right way to define m_unitWriteLock as static? what you recommend for such a situation? tnx.

@SotiriosDelimanolis: because this is going to be called 1000 times with separated objects. — tokhi, Aug 29 '13 at 15:48
That's not a good reason for it to be `static`. Maybe you should extract it to another Class which you instantiate. — Sotirios Delimanolis, Aug 29 '13 at 15:49
then this class would be instantiated many times and I get `too many open files` error. — tokhi, Aug 29 '13 at 15:51
Agree in principle. Encapsulation is a friend to thread safety and designing carefully crafted classes is the best way to achieve this goal. The use of static members when instance members would also present a viable solution can be expected to make achieving thread safety more complex. — scottb, Aug 29 '13 at 17:02

score 2 · Answer 1 · answered Aug 29 '13 at 15:49

2

Yes, why not?

If you method is static, the lock must be static as well. The question is: Does the method need to be static? But that depends on the problem you are going to solve.

answered Aug 29 '13 at 15:49

roehrijn

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Java - Reentrant WriteLock on static methods

1 Answers1