Package org.jppf.nio

Interface SelectorSynchronizer

All Known Implementing Classes:

SelectorSynchronizerImpl, SelectorSynchronizerLock

public interface SelectorSynchronizer

Synchronization aid for a Selector, to prevent SelectionKey.interestOps(int) invocations from blocking for too long.

Usage pattern:

- in the selection loop:

 SelectorSynchronizer sync = ...;
 
 try {
   int n = 0;
   while (true) {
     sync.waitForZeroAndSetToMinusOne();
     try {
       n = selector.select(selectTimeout);
     } finally {
       sync.setToZeroIfNegative();
     }
     if (n > 0) {
       // process selected keys
     }
   }
 } catch (Exception e) {
   // process exception
 }
 

- in separate threads:

 public void setInterestOps(SelectionKey key, int newOps) throws Exception {
   sync.wakeUpAndSetOrIncrement();
   try {
     key.interestOps(newOps);
   } finally {
     sync.decrement();
   }
 }
 

Author:

Laurent Cohen

Method Summary

Modifier and Type	Method	Description
void	decrement()	Decrement the value.
void	setToZeroIfNegative()	Set the value to zero if it is less than 0.
void	waitForZeroAndSetToMinusOne()	Wait for the value to go down to zero, then set it to -1.
void	wakeUpAndSetOrIncrement()	Compare the value with the expected value, and run an action and increment the value if the comparison succeeds, or set the value to the update value if it does not succeed.

Method Details

waitForZeroAndSetToMinusOne

void waitForZeroAndSetToMinusOne()

Wait for the value to go down to zero, then set it to -1.

setToZeroIfNegative

void setToZeroIfNegative()

Set the value to zero if it is less than 0.

decrement

void decrement()

Decrement the value.

wakeUpAndSetOrIncrement

void wakeUpAndSetOrIncrement()

Compare the value with the expected value, and run an action and increment the value if the comparison succeeds, or set the value to the update value if it does not succeed.