org.eclipse.rdf4j.common.concurrent.locks

## Class LockManager

- java.lang.Object
- - org.eclipse.rdf4j.common.concurrent.locks.LockManager

-     public class LockManager
      extends Object

  Manages a set of active locks. If any active lock is garbage collected it is automatically removed from the set and logged.
  Author:
    James Leigh

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `LockManager()` Create a new set of locks.
    `LockManager(boolean trackLocks)` Creates a new set of locks, optionally with lock tracking enabled.
    `LockManager(boolean trackLocks, int collectionFrequency)` Creates a new set of locks, optionally with lock tracking enabled.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Lock` | `createLock(String alias)` Creates a new active lock.
    `boolean` | `isActiveLock()` If any locks in this collection that are still active.
    `void` | `waitForActiveLocks()` Blocks current thread until the number of active locks has reached zero.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### LockManager

          public LockManager()

      Create a new set of locks.

    - #### LockManager

          public LockManager(boolean trackLocks)

      Creates a new set of locks, optionally with lock tracking enabled.
      Parameters:
        `trackLocks` - Controls whether to keep a stack trace of active locks. Enabling lock tracking will add some overhead, but can be very useful for debugging.

    - #### LockManager

          public LockManager(boolean trackLocks,
                             int collectionFrequency)

      Creates a new set of locks, optionally with lock tracking enabled.
      Parameters:
        `trackLocks` - Controls whether to keep a stack trace of active locks. Enabling lock tracking will add some overhead, but can be very useful for debugging.
        `collectionFrequency` - Number of milliseconds to block the first thread, waiting for active locks to finish, before running the memory garbage collection, to free abandoned active locks.

  - ### Method Detail

    - #### isActiveLock

          public boolean isActiveLock()

      If any locks in this collection that are still active.
      Returns:
        `true` of one or more locks that have not be released.

    - #### waitForActiveLocks

          public void waitForActiveLocks()
                                  throws InterruptedException

      Blocks current thread until the number of active locks has reached zero.
      Throws:
        `InterruptedException` - if any thread interrupted the current thread before or while the current thread was waiting for a notification. The interrupted status of the current thread is cleared when this exception is thrown.

    - #### createLock

          public Lock createLock(String alias)

      Creates a new active lock. This increases the number of active locks until its `Lock.release()` method is called, which decreases the number of active locks by the same amount.
      Parameters:
        `alias` - a short string used to log abandon locks
      Returns:
        an active lock

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