Package org.aksw.commons.util.ref

Class RefImpl<T>

java.lang.Object
org.aksw.commons.util.ref.RefImpl<T>
Type Parameters:
T -
All Implemented Interfaces:
AutoCloseable, Ref<T>
public class RefImpl<T> extends Object implements Ref<T>
Implementation of a Ref TODO Avoid needless synchronization; a ConcurrentHashMap may help; ref.equals could do only reference comparison
Author:
raven

  • Field Details

    • traceAcquisitions

      protected boolean traceAcquisitions

    • value

      protected T value

    • releaseAction

      protected AutoCloseable releaseAction
      The release action is run once immediately when the isAlive() state changes to false. The release action cannot 'revive' a reference as the reference is already 'dead'. The release action differs depending on how a reference was created: On the root reference, the releaseAction releases the wrapped resource On a child reference, the releaseAction releases itself (the child) from the parent one.

    • synchronizer

      protected Object synchronizer
      Object on which to synchronize on before any change of state of this reference. This allows for e.g. synchronizing on a Map<K, Reference<V>, such that closing a reference removes the map entry before it can be accessed and conversely, synchronizing on the map prevents the reference from becoming released. TODO Point to the ClaimingLoadingCache implementation

    • comment

      protected Object comment

    • parent

      protected RefImpl<T> parent

    • isClosed

      protected volatile boolean isClosed

    • acquisitionStackTrace

      protected StackTraceElement[] acquisitionStackTrace

    • closeStackTrace

      protected StackTraceElement[] closeStackTrace

    • closeTriggerStackTrace

      protected StackTraceElement[] closeTriggerStackTrace

    • childRefs

      protected Map<Ref<T>,Object> childRefs

    • activeChildRefs

      protected volatile int activeChildRefs

  • Constructor Details

  • Method Details

    • finalize

      protected void finalize() throws Throwable
      TODO Switch to Java 9 Cleaner once we upgrade
      Overrides:
      finalize in class Object
      Throws:
      Throwable

    • getComment

      public Object getComment()

    • getSynchronizer

      public Object getSynchronizer()
      Description copied from interface: Ref
      Return the object on which reference acquisition, release and the close action are synchronized on.
      Specified by:
      getSynchronizer in interface Ref<T>

    • get

      public T get()
      Description copied from interface: Ref
      Get the referent only iff this ref instance has not yet been closed. This method fails for closed alive refs. A closed reference is alive if it has unclosed child references. For most use cases the referent should be accessed using this method.
      Specified by:
      get in interface Ref<T>
      Returns:
      The referent

    • acquire

      public Ref<T> acquire(Object comment)
      Description copied from interface: Ref
      Acquire a new reference with a given comment object Acquiration fails if isAlive() returns false
      Specified by:
      acquire in interface Ref<T>
      Returns:

    • release

      protected void release(Object childRef)

    • isAlive

      public boolean isAlive()
      Description copied from interface: Ref
      A reference may itself be closed, but references to it may keep it alive
      Specified by:
      isAlive in interface Ref<T>
      Returns:
      true iff either this reference is not closed or there exists any acquired reference.

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Ref<T>

    • checkRelease

      protected void checkRelease()

    • fromCloseable

      public static <T extends AutoCloseable> Ref<T> fromCloseable(T value, Object synchronizer)

    • create2

      public static <T> Ref<T> create2(T value, Object synchronizer, Consumer<? super T> closer)
      Create method where the close action is created from a provided lambda that accepts the value

    • create

      public static <T> Ref<T> create(T value, Object synchronizer, AutoCloseable releaseAction)

    • create

      public static <T> Ref<T> create(T value, Object synchronizer, AutoCloseable releaseAction, Object comment)

    • createClosed

      public static <T> Ref<T> createClosed()

    • isClosed

      public boolean isClosed()
      Description copied from interface: Ref
      Check whether this reference is closed
      Specified by:
      isClosed in interface Ref<T>

    • getRootRef

      public Ref<T> getRootRef()
      Description copied from interface: Ref
      Get the root reference
      Specified by:
      getRootRef in interface Ref<T>

    • getAcquisitionStackTrace

      public StackTraceElement[] getAcquisitionStackTrace()
      Description copied from interface: Ref
      Optional operation. References may expose where they were acquired
      Specified by:
      getAcquisitionStackTrace in interface Ref<T>
      Returns:

    • getCloseStackTrace

      public StackTraceElement[] getCloseStackTrace()
      Specified by:
      getCloseStackTrace in interface Ref<T>

    • getCloseTriggerStackTrace

      public StackTraceElement[] getCloseTriggerStackTrace()
      Specified by:
      getCloseTriggerStackTrace in interface Ref<T>

    • toString

      public String toString()
      Overrides:
      toString in class Object