ReferenceQueue

public class ReferenceQueue
extends Object

java.lang.Object
↳	java.lang.ref.ReferenceQueue<T>

Reference queues, to which registered reference objects are appended by the garbage collector after the appropriate reachability changes are detected.

Summary

Public constructors
`ReferenceQueue()` Constructs a new reference-object queue.

Public methods
`Reference<? extends T>`	`poll()` Polls this queue to see if a reference object is available.
`Reference<? extends T>`	`remove(long timeout)` Removes the next reference object in this queue, blocking until either one becomes available or the given timeout period expires.
`Reference<? extends T>`	`remove()` Removes the next reference object in this queue, blocking until one becomes available.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public constructors

ReferenceQueue

Added in API level 1

public ReferenceQueue ()

Constructs a new reference-object queue.

Public methods

poll

Added in API level 1

public Reference<? extends T> poll ()

Polls this queue to see if a reference object is available. If one is available without further delay then it is removed from the queue and returned. Otherwise this method immediately returns null.

Returns
`Reference<? extends T>`	A reference object, if one was immediately available, otherwise `null`

remove

Added in API level 1

public Reference<? extends T> remove (long timeout)

Removes the next reference object in this queue, blocking until either one becomes available or the given timeout period expires.

This method does not offer real-time guarantees: It schedules the timeout as if by invoking the Object#wait(long) method.

Parameters
`timeout`	`long`: If positive, block for up to `timeout` milliseconds while waiting for a reference to be added to this queue. If zero, block indefinitely.

Returns
`Reference<? extends T>`	A reference object, if one was available within the specified timeout period, otherwise `null`

Throws
`IllegalArgumentException`	If the value of the timeout argument is negative
`InterruptedException`	If the timeout wait is interrupted

remove

Added in API level 1

public Reference<? extends T> remove ()

Removes the next reference object in this queue, blocking until one becomes available.

Returns
`Reference<? extends T>`	A reference object, blocking until one becomes available

Throws
`InterruptedException`	If the wait is interrupted