Class DefaultLockRegistry

All Implemented Interfaces:

public final class DefaultLockRegistry extends Object implements LockRegistry
Default implementation of LockRegistry which uses Masked Hashcode algorithm to obtain locks. When an instance of this class is created and array of Lock objects is created. The length of the array is based on the 'mask' parameter passed in the constructor. The default mask is 0xFF which will create and array consisting of 256 ReentrantLock instances. When the obtain(Object) method is called with the lockKey (e.g., Object) the index of the Lock is determined by masking the object's hashCode (e.g., object.hashCode & mask) and the Lock is returned.
Oleg Zhurakousky, Gary Russell
  • Constructor Details

    • DefaultLockRegistry

      public DefaultLockRegistry()
      Constructs a DefaultLockRegistry with the default mask 0xFF with 256 locks.
    • DefaultLockRegistry

      public DefaultLockRegistry(int mask)
      Constructs a DefaultLockRegistry with the supplied mask - the mask must have a value Math.pow(2, n) - 1 where n is 1 to 31, creating a hash of Math.pow(2, n) locks.


      • 0x3ff (1023) - 1024 locks
      • 0xfff (4095) - 4096 locks
      mask - The bit mask.
  • Method Details

    • obtain

      public Lock obtain(Object lockKey)
      Obtains a lock by masking the lockKey's hashCode() with the mask and using the result as an index to the lock table.
      Specified by:
      obtain in interface LockRegistry
      lockKey - the object used to derive the lock index.
      The associated lock.