Package org.apache.tomcat.util.threads
Class ThreadPoolExecutor.DiscardOldestPolicy
java.lang.Object
org.apache.tomcat.util.threads.ThreadPoolExecutor.DiscardOldestPolicy
- All Implemented Interfaces:
- ThreadPoolExecutor.RejectedExecutionHandler
- Enclosing class:
- ThreadPoolExecutor
public static class ThreadPoolExecutor.DiscardOldestPolicy
extends Object
implements ThreadPoolExecutor.RejectedExecutionHandler
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. This policy is
 rarely useful in cases where other threads may be waiting for
 tasks to terminate, or failures must be recorded. Instead consider
 using a handler of the form:
  
 new RejectedExecutionHandler() {
   public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
     Runnable dropped = e.getQueue().poll();
     if (dropped instanceof Future<?>) {
       ((Future<?>)dropped).cancel(false);
       // also consider logging the failure
     }
     e.execute(r);  // retry
 }}- 
Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptionvoidObtains 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.
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Constructor Details- 
DiscardOldestPolicypublic DiscardOldestPolicy()Creates aDiscardOldestPolicyfor the given executor.
 
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Method Details- 
rejectedExecutionObtains 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.- Specified by:
- rejectedExecutionin interface- ThreadPoolExecutor.RejectedExecutionHandler
- Parameters:
- r- the runnable task requested to be executed
- e- the executor attempting to execute this task
 
 
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