Are Locks AutoCloseable?

java resources java-7 resource-management locks
fredoverflow picture fredoverflow · Aug 6, 2011 · Viewed 13.7k times · Source

Are Locks auto-closeable? That is, instead of:

Lock someLock = new ReentrantLock();
someLock.lock();
try
{
    // ...
}
finally
{
    someLock.unlock();
}

...can I say:

try (Lock someLock = new ReentrantLock())
{
    someLock.lock();
    // ...
}

...in Java 7?

Answer

Stephen picture Stephen · Jun 12, 2012

I was looking into doing this myself and did something like this: 

public class CloseableReentrantLock extends ReentrantLock implements AutoCloseable { 
   public CloseableReentrantLock open() { 
      this.lock();
      return this;
   }

   @Override
   public void close() {
      this.unlock();
   }
}

and then this as usage for the class:

public class MyClass {
   private final CloseableReentrantLock lock = new CloseableReentrantLock();

   public void myMethod() {
      try(CloseableReentrantLock closeableLock = lock.open()) {
         // locked stuff
      }
   }
}

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