ThreadPoolExecutor.DiscardOldestPolicy
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A handler for rejected tasks that discards the oldest unhandled
request and then retries execute
, unless the executor
is shut down, in which case the task is discarded.
Public Constructor Summary
Public Method Summary
void
|
rejectedExecution( Runnable r, ThreadPoolExecutor e)
Obtains and ignores the next task that the executor
would otherwise execute, if one is immediately available,
and then retries execution of task r, unless the executor
is shut down, in which case task r is instead discarded.
|
Inherited Method Summary
From class
java.lang.Object
Object
|
clone()
Creates and returns a copy of this Object .
|
boolean
|
equals( Object obj)
Compares this instance with the specified object and indicates if they
are equal.
|
void
|
finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
|
final
Class<?>
|
getClass()
Returns the unique instance of Class that represents this
object's class.
|
int
|
hashCode()
Returns an integer hash code for this object.
|
final
void
|
notify()
Causes a thread which is waiting on this object's monitor (by means of
calling one of the wait() methods) to be woken up.
|
final
void
|
notifyAll()
Causes all threads which are waiting on this object's monitor (by means
of calling one of the wait() methods) to be woken up.
|
String
|
toString()
Returns a string containing a concise, human-readable description of this
object.
|
final
void
|
wait(long timeout, int nanos)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait(long timeout)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait()
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.
|
Public Constructors
public
DiscardOldestPolicy
()
Creates a DiscardOldestPolicy
for the given executor.
Public Methods
Obtains and ignores the next task that the executor
would otherwise execute, if one is immediately available,
and then retries execution of task r, unless the executor
is shut down, in which case task r is instead discarded.
Parameters
r |
the runnable task requested to be executed |
e |
the executor attempting to execute this task
|
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Last updated 2024-07-10 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-07-10 UTC."],[[["\u003cp\u003e\u003ccode\u003eThreadPoolExecutor.DiscardOldestPolicy\u003c/code\u003e is a handler for rejected tasks in a \u003ccode\u003eThreadPoolExecutor\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eIt discards the oldest unhandled task and attempts to retry the current task.\u003c/p\u003e\n"],["\u003cp\u003eIf the executor is shut down, the task is discarded instead of being retried.\u003c/p\u003e\n"],["\u003cp\u003eThis policy is implemented by the \u003ccode\u003erejectedExecution\u003c/code\u003e method, which handles the task rejection logic.\u003c/p\u003e\n"]]],["`DiscardOldestPolicy` handles rejected tasks in a `ThreadPoolExecutor`. It discards the oldest unhandled request, then retries executing the current task. If no task is readily available, the current task is ignored. If the executor is shut down, the current task is discarded without retry. This class provides a constructor `DiscardOldestPolicy()` and a method `rejectedExecution(Runnable r, ThreadPoolExecutor e)` to manage task rejection.\n"],null,["public static class **ThreadPoolExecutor.DiscardOldestPolicy** extends [Object](../../../../reference/java/lang/Object.html) \nimplements [RejectedExecutionHandler](../../../../reference/java/util/concurrent/RejectedExecutionHandler.html) \nA handler for rejected tasks that discards the oldest unhandled\nrequest and then retries `execute`, unless the executor\nis shut down, in which case the task is discarded. \n\nPublic Constructor Summary\n\n|---|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| | [DiscardOldestPolicy](../../../../reference/java/util/concurrent/ThreadPoolExecutor.DiscardOldestPolicy.html#DiscardOldestPolicy())() Creates a `DiscardOldestPolicy` for the given executor. |\n\nPublic Method Summary\n\n|------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| void | [rejectedExecution](../../../../reference/java/util/concurrent/ThreadPoolExecutor.DiscardOldestPolicy.html#rejectedExecution(java.lang.Runnable,%20java.util.concurrent.ThreadPoolExecutor))([Runnable](../../../../reference/java/lang/Runnable.html) r, [ThreadPoolExecutor](../../../../reference/java/util/concurrent/ThreadPoolExecutor.html) e) Obtains and ignores the next task that the executor would otherwise execute, if one is immediately available, and then retries execution of task r, unless the executor is shut down, in which case task r is instead discarded. |\n\nInherited Method Summary \nFrom class [java.lang.Object](../../../../reference/java/lang/Object.html) \n\n|----------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| [Object](../../../../reference/java/lang/Object.html) | [clone](../../../../reference/java/lang/Object.html#clone())() Creates and returns a copy of this `Object`. |\n| boolean | [equals](../../../../reference/java/lang/Object.html#equals(java.lang.Object))([Object](../../../../reference/java/lang/Object.html) obj) Compares this instance with the specified object and indicates if they are equal. |\n| void | [finalize](../../../../reference/java/lang/Object.html#finalize())() Invoked when the garbage collector has detected that this instance is no longer reachable. |\n| final [Class](../../../../reference/java/lang/Class.html)\\\u003c?\\\u003e | [getClass](../../../../reference/java/lang/Object.html#getClass())() Returns the unique instance of [Class](../../../../reference/java/lang/Class.html) that represents this object's class. |\n| int | [hashCode](../../../../reference/java/lang/Object.html#hashCode())() Returns an integer hash code for this object. |\n| final void | [notify](../../../../reference/java/lang/Object.html#notify())() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |\n| final void | [notifyAll](../../../../reference/java/lang/Object.html#notifyAll())() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |\n| [String](../../../../reference/java/lang/String.html) | [toString](../../../../reference/java/lang/Object.html#toString())() Returns a string containing a concise, human-readable description of this object. |\n| final void | [wait](../../../../reference/java/lang/Object.html#wait(long,%20int))(long timeout, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |\n| final void | [wait](../../../../reference/java/lang/Object.html#wait(long))(long timeout) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |\n| final void | [wait](../../../../reference/java/lang/Object.html#wait())() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object. |\n\nFrom interface [java.util.concurrent.RejectedExecutionHandler](../../../../reference/java/util/concurrent/RejectedExecutionHandler.html) \n\n|---------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| abstract void | [rejectedExecution](../../../../reference/java/util/concurrent/RejectedExecutionHandler.html#rejectedExecution(java.lang.Runnable,%20java.util.concurrent.ThreadPoolExecutor))([Runnable](../../../../reference/java/lang/Runnable.html) r, [ThreadPoolExecutor](../../../../reference/java/util/concurrent/ThreadPoolExecutor.html) executor) Method that may be invoked by a [ThreadPoolExecutor](../../../../reference/java/util/concurrent/ThreadPoolExecutor.html) when [execute](../../../../reference/java/util/concurrent/ThreadPoolExecutor.html#execute(java.lang.Runnable)) cannot accept a task. |\n\nPublic Constructors \n\npublic\n**DiscardOldestPolicy**\n() \nCreates a `DiscardOldestPolicy` for the given executor.\n\nPublic Methods \n\npublic void\n**rejectedExecution**\n([Runnable](../../../../reference/java/lang/Runnable.html) r, [ThreadPoolExecutor](../../../../reference/java/util/concurrent/ThreadPoolExecutor.html) e) \nObtains and ignores the next task that the executor\nwould otherwise execute, if one is immediately available,\nand then retries execution of task r, unless the executor\nis shut down, in which case task r is instead discarded. \n\nParameters\n\n| r | the runnable task requested to be executed |\n| e | the executor attempting to execute this task |\n|---|----------------------------------------------|"]]