模块 wjybxx.commons.disruptor
程序包 cn.wjybxx.disruptor

类 SingleProducerSequencer

java.lang.Object
cn.wjybxx.disruptor.RingBufferSequencer
cn.wjybxx.disruptor.SingleProducerSequencer
所有已实现的接口:
ProducerBarrier, SequenceBarrier, Sequencer
public final class SingleProducerSequencer extends RingBufferSequencer
单生产者序号分配器 （由用户保证不会并发的申请序号）
作者:
wjybxx date - 2024/1/17

  • 构造器详细资料

    • SingleProducerSequencer

      public SingleProducerSequencer(int bufferSize, long sleepNanos, WaitStrategy waitStrategy, @Nullable SequenceBlocker blocker)

  • 方法详细资料

    • claim

      public void claim(long sequence)
      从接口复制的说明: SequenceBarrier
      设置当前屏障的序号。 1. 仅在初始化屏障时使用。 2. 这是个很危险的方法，避免在运行中使用，否则可能导致错误。 3. 屏障的默认初始值为SequenceBarrier.INITIAL_SEQUENCE。
      指定者:
      claim 在接口中 SequenceBarrier
      覆盖:
      claim 在类中 RingBufferSequencer
      参数:
      sequence - 要初始化的值

    • remainingCapacity

      public long remainingCapacity()
      从类复制的说明: RingBufferSequencer
      当前剩余容量。 并不一定具有价值，因为多线程模型下查询容器的当前大小，它反映的总是一个旧值。

      Get the remaining capacity for this sequencer.

      指定者:
      remainingCapacity 在类中 RingBufferSequencer
      返回:
      The number of slots remaining.

    • hasAvailableCapacity

      public boolean hasAvailableCapacity(int requiredCapacity)
      从接口复制的说明: ProducerBarrier
      是否有足够的空间 Has the buffer got capacity to allocate another sequence. This is a concurrent method so the response should only be taken as an indication of available capacity.
      参数:
      requiredCapacity - in the buffer
      返回:
      true if the buffer has the capacity to allocate the next sequence otherwise false.

    • next

      public long next()
      从接口复制的说明: ProducerBarrier
      获取下一个事件的序号，空间不足时会阻塞(等待)。 申请完空间之后,必须使用 ProducerBarrier.publish(long) 发布，否则会导致整个数据结构不可用。

      Claim the next event in sequence for publishing.

      返回:
      the claimed sequence value

    • next

      public long next(int n)
      从接口复制的说明: ProducerBarrier
      获取接下来的n个事件的序号，空间不足时会阻塞(等待)。 申请完空间之后，必须使用 ProducerBarrier.publish(long, long) 发布，否则会导致整个数据结构不可用

      Claim the next n events in sequence for publishing. This is for batch event producing. Using batch producing requires a little care and some math. 

       int n = 10;
 long hi = sequencer.next(n);
 long lo = hi - (n - 1);
 for (long sequence = lo; sequence <= hi; sequence++) {
     // Do work.
 }
 sequencer.publish(lo, hi);
      参数:
      n - the number of sequences to claim
      返回:
      the highest claimed sequence value

    • nextInterruptibly

      public long nextInterruptibly() throws InterruptedException
      从接口复制的说明: ProducerBarrier
      在ProducerBarrier.next()基础上会响应中断请求
      抛出:
      InterruptedException - 如果申请期间线程被中断

    • nextInterruptibly

      public long nextInterruptibly(int n) throws InterruptedException
      从接口复制的说明: ProducerBarrier
      在ProducerBarrier.next(int)基础上会响应中断请求
      抛出:
      InterruptedException - 如果申请期间线程被中断

    • tryNext

      public long tryNext()
      从接口复制的说明: ProducerBarrier
      尝试获取下一个事件的序列 -- 不会阻塞。 申请完空间之后,必须使用 ProducerBarrier.publish(long) 发布，否则会导致整个数据结构不可用。

      Attempt to claim the next event in sequence for publishing. Will return the number of the slot if there is at least requiredCapacity slots available.

      返回:
      申请成功则返回对应的序号，否则返回 -1

    • tryNext

      public long tryNext(int n)
      从接口复制的说明: ProducerBarrier
      尝试获取接下来n个数据的最后一个数据索引位置 -- 不会阻塞。 申请完空间之后，必须使用 ProducerBarrier.publish(long, long) 发布，否则会导致整个数据结构不可用 使用该方法可以避免死锁

      Attempt to claim the next n events in sequence for publishing. Will return the highest numbered slot if there is at least requiredCapacity slots available. Have a look at ProducerBarrier.next() for a description on how to use this method.

      参数:
      n - 需要申请的序号数量
      返回:
      申请成功则返回对应的序号，否则返回 -1

    • publish

      public void publish(long sequence)
      从接口复制的说明: ProducerBarrier
      发布指定序号的数据，表示sequence对应的数据可用 Publishes a sequence. Call when the event has been filled.
      参数:
      sequence - the sequence to be published.

    • publish

      public void publish(long lo, long hi)
      从接口复制的说明: ProducerBarrier
      批量发布数据，表示 [lowest,highest]区间段整段数据可用。 一般情况下，hi是ProducerBarrier.next()等方法申请到的最大序号，但也可能不是，生产者可能分段发布数据，以避免阻塞消费者。

      Batch publish sequences. Called when all of the events have been filled.

      参数:
      lo - first sequence number to publish
      hi - last sequence number to publish

    • isPublished

      public boolean isPublished(long sequence)
      从接口复制的说明: ProducerBarrier
      指定序号的数据是否已发布。 注意： 1. 该测试只测试序号自身，不测试其前置序号。 2. 通常情况下你不应该使用它，唯一合理的情况是：清理RingBuffer的时候。

      Confirms if a sequence is published and the event is available for use; non-blocking.

      参数:
      sequence - of the buffer to check
      返回:
      true if the sequence is available for use, false if not

    • getHighestPublishedSequence

      public long getHighestPublishedSequence(long nextSequence, long availableSequence)
      从接口复制的说明: ProducerBarrier
      查询 [nextSequence , availableSequence] 区间段之间连续发布的最大序号。 该接口用于消费者屏障查询真实可用的序号。

      由于多线程的生产者是先申请序号，再发布数据；因此SequenceBarrier.sequence()指向的是即将发布数据的槽，而不一定已经具备数据。 而消费者只能顺序消费，因此【只要消费者的依赖可能包含生产者】，在观察到依赖的最大可用序号后，都应该查询真实可用的序号。

      Get the highest sequence number that can be safely read from the ring buffer. Depending on the implementation of the Sequencer this call may need to scan a number of values in the Sequencer. The scan will range from nextSequence to availableSequence. If there are no available values >= nextSequence the return value will be nextSequence - 1. To work correctly a consumer should pass a value that is 1 higher than the last sequence that was successfully processed.

      参数:
      nextSequence - The sequence to start scanning from.
      availableSequence - The sequence to scan to.
      返回:
      The highest value that can be safely read, will be at least nextSequence - 1.