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June 27, 2024 14:10
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| /** | |
| * A custom ThreadPoolTaskExecutor based on this SO answer https://stackoverflow.com/a/24493856. | |
| * | |
| * The main distinction of this executor is that it will not wait for the queue to be full before scaling up the number | |
| * of threads in the pool. Instead, it will scale up the number of threads in the pool (up to the maximum) as soon as | |
| * a new task is submitted and no idle threads are available to run it. Then, once the number of threads reaches the | |
| * maximum, it will start to queue tasks. | |
| */ | |
| class ImmediatelyScalingThreadPoolTaskExecutor : ThreadPoolTaskExecutor() { | |
| override fun createQueue(queueCapacity: Int): BlockingQueue<Runnable> { | |
| return object : LinkedTransferQueue<Runnable>() { | |
| override fun offer(e: Runnable): Boolean { | |
| // tryTransfer will return false if no thread is available to run the task which will cause the thread | |
| // pool to either spawn a new thread or reject the task. If the task is rejected, the custom | |
| // RejectedExecutionHandler will put the task into the queue | |
| return tryTransfer(e) | |
| } | |
| } | |
| } | |
| override fun initializeExecutor(threadFactory: ThreadFactory, ignore: RejectedExecutionHandler): ExecutorService { | |
| val rejectedExecutionHandler = RejectedExecutionHandler { r, executor -> | |
| try { | |
| executor.queue.put(r) | |
| } catch (e: InterruptedException) { | |
| Thread.currentThread().interrupt() | |
| } | |
| } | |
| return super.initializeExecutor(threadFactory, rejectedExecutionHandler) | |
| } | |
| } |
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