ReferenceCountingCloseableObject (druid-processing 28.0.0 API)

java.lang.Object
- org.apache.druid.segment.ReferenceCountingCloseableObject<BaseObject>

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

ReferenceCountingIndexedTable, ReferenceCountingSegment
```
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 called increment() or incrementReferenceAndDecrementOnceCloseable(), but have not called decrement() yet or the closer for incrementReferenceAndDecrementOnceCloseable(), and the wrapped object won't be actually closed until that all references are released.

Field Summary

Fields
Modifier and Type Field Description

protected BaseObject baseObject

protected Phaser referents

Constructor Summary

Constructors
Constructor Description

ReferenceCountingCloseableObject(BaseObject object)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`
`void`	`decrement()`	Decrement the reference count by one.
`Closeable`	`decrementOnceCloseable()`	Returns a `Closeable` which action is to call `decrement()` only once.
`int`	`getNumReferences()`
`boolean`	`increment()`	Increment the reference count by one.
`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.
`boolean`	`isClosed()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - referents
```
protected final Phaser referents
```
  - baseObject
```
protected final BaseObject extends Closeable baseObject
```
- Constructor Detail
  - ReferenceCountingCloseableObject
```
public ReferenceCountingCloseableObject(BaseObject object)
```
- Method Detail
  - 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