org.apache.druid.segment.ReferenceCountingCloseableObject<BaseObject>

Direct Known Subclasses:: ReferenceCountedIndexedTableProvider, ReferenceCountedSegmentProvider

public abstract class ReferenceCountingCloseableObject<BaseObject extends Closeable> extends Object implements Closeable

ReferenceCountingCloseableObject implements something like automatic reference count-based resource management, backed by a Phaser.

ReferenceCountingCloseableObject allows consumers to call close() before some other "users" which have checked out references via increment() or incrementReferenceAndDecrementOnceCloseable(), but have not called decrement() yet or the closer for incrementReferenceAndDecrementOnceCloseable(). The wrapped object won't be closed until all references are released.

Field Details
- referents
  
  protected final Phaser referents
- baseObject
  
  protected final BaseObject extends Closeable baseObject
Constructor Details
- ReferenceCountingCloseableObject
  
  public ReferenceCountingCloseableObject(BaseObject object)
Method Details
- getNumReferences
  
  public int getNumReferences()
- isClosed
  
  public boolean isClosed()
- increment
  
  public boolean increment()
  
  Increment the reference count by one.
- decrement
  
  public void decrement()
  
  Decrement the reference count by one.
- incrementReferenceAndDecrementOnceCloseable
  
  public Optional<Closeable> incrementReferenceAndDecrementOnceCloseable()
  
  Returns an Optional of a Closeable from decrementOnceCloseable(), if it is able to successfully increment(), else nothing indicating that the reference could not be acquired.
- decrementOnceCloseable
  
  public Closeable decrementOnceCloseable()
  
  Returns a Closeable which action is to call decrement() only once. If close() is called on the returned Closeable object for the second time, it won't call decrement() again.
- close
  
  public void close()
  
  Specified by:
  
  close in interface AutoCloseable
  
  Specified by:
  
  close in interface Closeable

Class ReferenceCountingCloseableObject<BaseObject extends Closeable>

Field Summary