Module org.eclipse.jetty.io

Package org.eclipse.jetty.io

Class Retainable.ReferenceCounter

java.lang.Object

org.eclipse.jetty.io.Retainable.ReferenceCounter

All Implemented Interfaces:

Retainable

Enclosing interface:

Retainable

public static class Retainable.ReferenceCounter
extends Object
implements Retainable

A reference count implementation for a Retainable resource.

The reference count is initialized to 1 when the resource is created, and therefore it is implicitly retained and needs a call to release().

Additional calls to retain() must be matched by correspondent calls to release().

When the reference count goes to zero, the resource may be pooled. When the resource is acquired from the pool, acquire() should be called to set the reference count to 1.

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.jetty.io.Retainable

Retainable.ReferenceCounter, Retainable.Wrapper

Constructor Summary

Constructors

Modifier	Constructor	Description
	ReferenceCounter()
protected	ReferenceCounter(int initialCount)

Method Summary

Modifier and Type	Method	Description
void	acquire()	Updates the reference count from 0 to 1.
boolean	canRetain()	Returns whether this resource is referenced counted by calls to Retainable.retain() and Retainable.release().
int	get()
boolean	isRetained()	Returns whether retain() has been called at least one more time than release().
boolean	release()	Releases this resource, potentially decrementing a reference count (if any).
void	retain()	Retains this resource, potentially incrementing a reference count if there are resources that will be released.
String	toString()
boolean	tryRetain()

Methods inherited from class java.lang.Object

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

Constructor Details

ReferenceCounter

public ReferenceCounter()

ReferenceCounter

protected ReferenceCounter(int initialCount)

Method Details

get

public int get()

Returns:

the current reference count

acquire

public void acquire()

Updates the reference count from 0 to 1.

This method should only be used when this resource is acquired from a pool.

canRetain

public boolean canRetain()

Description copied from interface: Retainable

Returns whether this resource is referenced counted by calls to Retainable.retain() and Retainable.release().

Implementations may decide that special resources are not not referenced counted (for example, static constants) so calling Retainable.retain() is a no-operation, and calling Retainable.release() on those special resources is a no-operation that always returns true.

Specified by:

canRetain in interface Retainable

Returns:

true if calls to Retainable.retain() are reference counted.

retain

public void retain()

Description copied from interface: Retainable

Retains this resource, potentially incrementing a reference count if there are resources that will be released.

Specified by:

retain in interface Retainable

tryRetain

public boolean tryRetain()

release

public boolean release()

Description copied from interface: Retainable

Releases this resource, potentially decrementing a reference count (if any).

Specified by:

release in interface Retainable

Returns:

true when the reference count goes to zero or if there was no reference count, false otherwise.

isRetained

public boolean isRetained()

Returns whether retain() has been called at least one more time than release().

Returns:

whether this buffer is retained

toString

public String toString()

Overrides:

toString in class Object