Package io.micronaut.http.netty

Class EventLoopFlow

java.lang.Object

io.micronaut.http.netty.EventLoopFlow

@Internal
public final class EventLoopFlow
extends Object

This class forwards reactive operations onto an EventLoop if they are called from outside that loop. It avoids unnecessary Executor.execute(java.lang.Runnable) calls when the reactive methods are called inside the loop. All the while it ensures the operations remain serialized (in the same order).

Should be used like this:

     public void onNext(Object item) {
         if (serializer.executeNow(() -> onNext0(item))) {
             onNext0(item);
         }
     }

     private void onNext0(Object item) {
         ...
     }
 

This class is not thread-safe: The invariants for calls to executeNow(java.lang.Runnable) are very strict. In particular:

• There must be no concurrent calls to executeNow(java.lang.Runnable).
• When executeNow(java.lang.Runnable) returns true, the subsequent execution of the child method (onNext0 in the above example) must fully complete before the next executeNow(java.lang.Runnable) call. This ensures that there are no concurrent calls to the child method.

Both of these invariants are guaranteed by the reactive spec, but may not apply to other use cases.

Since:

4.4.0

Author:

Jonas Konrad

Constructor Summary

Constructors

Constructor	Description
EventLoopFlow(io.netty.util.concurrent.OrderedEventExecutor loop)

Method Summary

Modifier and Type	Method	Description
boolean	executeNow(Runnable delayTask)	Determine whether the next step can be executed immediately.

Methods inherited from class java.lang.Object

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

Constructor Details

EventLoopFlow

public EventLoopFlow(io.netty.util.concurrent.OrderedEventExecutor loop)

Method Details

executeNow

public boolean executeNow(Runnable delayTask)

Determine whether the next step can be executed immediately. Iff this method returns true, delayTask will be ignored and the caller should call the target method manually. Iff this method returns false, the caller should take no further action as delayTask will be run in the future.

Parameters:

delayTask - The task to run if it can't be run immediately

Returns:

true if the caller should instead run the task immediately