Java Community | Help. Code. Learn.•9h ago

Asyncronous task queue

I have one thread that delegates tasks over to another thread, which runs those tasks in a queue. These tasks are blocking tasks (database), that I want to be run in the correct order, first in first out. Currently using BlockingQueue, but when testing it using junit, it can freeze the whole test. That's because after each test, this thread is waited on until it finishes. I have not found a good way to enable/disable the queue How would one do this properly?

32 Replies

JavaBot•9h ago

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dan1st•9h ago

Can you show the relevant code? Just the code that's necessary to reproduce the issue

Thorinwasher•9h ago

Sure, don't laugh at it though 🤣

dan1st•9h ago

And if possible, please also show where exactly the code blocks the tests - Is it somewhere during the test or after running the tests?

Thorinwasher•9h ago

Oh, too large...

dan1st•9h ago

I am fairly sure your code is better than the code of many other people - after all you are writing tests you can also try to upload the files

Thorinwasher•9h ago

Good point, I'm not educated enough in concurency though Ah

dan1st•9h ago

or ideally only include the relevant code

Thorinwasher•9h ago

let me do that then

dan1st•9h ago

concurrency is hard

Thorinwasher•9h ago

StargateQueuedAsyncT...

dan1st•9h ago

The most complicated chapter of the JVM specification (which specifies how JVMs have to work) is pretty much about what should happen in multithreaded environments

Thorinwasher•9h ago

I think you need more info than that though

dan1st•8h ago

Can you show the test and where it blocks?

Thorinwasher•8h ago

Sure, this is one test that blocks everything, but that relates to the test that ran before it It's quite layered though

    @Test
    void portalInvalidBlockPlaceTest() {
        Location bottomLeft = new Location(world, 0, 7, 0);
        Location insidePortal = new Location(world, 0, 9, 0);
        Block signBlock = PortalBlockGenerator.generatePortal(bottomLeft);
        Block irisBlock = new Location(world, 1, 9, 0).getBlock();


        ((Directional) signBlock.getBlockData()).setFacing(BlockFace.SOUTH);
        blockEventListener
                .onSignChange(new SignChangeEvent(signBlock, player, new String[]{"test", "", CUSTOM_NETNAME, ""}));

        BlockPlaceEvent event = new BlockPlaceEvent(irisBlock, irisBlock.getState(), irisBlock,
                new ItemStack(Material.ANDESITE), player, false);
        blockEventListener.onBlockPlace(event);
        blockEventListener.onBlockBreak(new BlockBreakEvent(insidePortal.getBlock(), player));
        Assertions.assertTrue(event.isCancelled());
    }

    @Test
    void portalInvalidBlockPlaceTest() {
        Location bottomLeft = new Location(world, 0, 7, 0);
        Location insidePortal = new Location(world, 0, 9, 0);
        Block signBlock = PortalBlockGenerator.generatePortal(bottomLeft);
        Block irisBlock = new Location(world, 1, 9, 0).getBlock();


        ((Directional) signBlock.getBlockData()).setFacing(BlockFace.SOUTH);
        blockEventListener
                .onSignChange(new SignChangeEvent(signBlock, player, new String[]{"test", "", CUSTOM_NETNAME, ""}));

        BlockPlaceEvent event = new BlockPlaceEvent(irisBlock, irisBlock.getState(), irisBlock,
                new ItemStack(Material.ANDESITE), player, false);
        blockEventListener.onBlockPlace(event);
        blockEventListener.onBlockBreak(new BlockBreakEvent(insidePortal.getBlock(), player));
        Assertions.assertTrue(event.isCancelled());
    }

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Asyncronous task queue