Package org.apache.pekko.actor.typed.scaladsl

Interface StashBuffer<T>

public interface StashBuffer<T>
A non thread safe mutable message buffer that can be used to buffer messages inside actors and then unstash them.

The buffer can hold at most the given capacity number of messages.

Not for user extension.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    capacity()
    What is the capacity of this buffer.
    void
    clear()
    Removes all messages from the buffer.
    <U> boolean
    contains(U message)
    Tests whether this StashBuffer contains a given message.
    boolean
    exists(scala.Function1<T,Object> predicate)
    Tests whether a predicate holds for at least one element of this StashBuffer.
    void
    foreach(scala.Function1<T,scala.runtime.BoxedUnit> f)
    Iterate over all elements of the buffer and apply a function to each element, without removing them.
    T
    head()
    Return the first element of the message buffer without removing it.
    boolean
    isEmpty()
    Check if the message buffer is empty.
    boolean
    isFull()
     
    boolean
    nonEmpty()
    Check if the message buffer is not empty.
    int
    size()
    How many elements are in the message buffer.
    StashBuffer<T>
    stash(T message)
    Add one element to the end of the message buffer.
    Behavior<T>
    unstash(Behavior<T> behavior, int numberOfMessages, scala.Function1<T,T> wrap)
    Transition to the given behavior and process numberOfMessages of the stashed messages.
    Behavior<T>
    unstashAll(Behavior<T> behavior)
    Transition to the given behavior and process all stashed messages.

  • Method Details

    • isEmpty

      boolean isEmpty()
      Check if the message buffer is empty.

      Returns:
      if the buffer is empty

    • nonEmpty

      boolean nonEmpty()
      Check if the message buffer is not empty.

      Returns:
      if the buffer is not empty

    • size

      int size()
      How many elements are in the message buffer.

      Returns:
      the number of elements in the message buffer

    • capacity

      int capacity()
      What is the capacity of this buffer.

      Returns:
      the capacity of this buffer

    • isFull

      boolean isFull()
      Returns:
      true if no more messages can be added, i.e. size equals the capacity of the stash buffer

    • stash

      StashBuffer<T> stash(T message)
      Add one element to the end of the message buffer.

      Parameters:
      message - the message to buffer
      Returns:
      this message buffer

    • head

      T head()
      Return the first element of the message buffer without removing it.

      Returns:
      the first element or throws NoSuchElementException if the buffer is empty
      Throws:
      NoSuchElementException - if the buffer is empty

    • foreach

      void foreach(scala.Function1<T,scala.runtime.BoxedUnit> f)
      Iterate over all elements of the buffer and apply a function to each element, without removing them.

      Parameters:
      f - the function to apply to each element

    • contains

      <U> boolean contains(U message)
      Tests whether this StashBuffer contains a given message.

      Parameters:
      message - the message to test
      Returns:
      true if the buffer contains the message, false otherwise.

    • exists

      boolean exists(scala.Function1<T,Object> predicate)
      Tests whether a predicate holds for at least one element of this StashBuffer.

      Parameters:
      predicate - the predicate used to test
      Returns:
      true if the predicate holds for at least one message, false otherwise.

    • clear

      void clear()
      Removes all messages from the buffer.

    • unstashAll

      Behavior<T> unstashAll(Behavior<T> behavior)
      Transition to the given behavior and process all stashed messages. Messages will be processed in the same order they arrived. The StashBuffer will be empty after processing all messages, unless an exception is thrown or messages are stashed while unstashing.

      If an exception is thrown by processing a message a proceeding messages and the message causing the exception have been removed from the StashBuffer, but unprocessed messages remain.

      It's allowed to stash messages while unstashing. Those newly added messages will not be processed by this call and have to be unstashed in another call.

      The behavior passed to unstashAll must not be unhandled.

    • unstash

      Behavior<T> unstash(Behavior<T> behavior, int numberOfMessages, scala.Function1<T,T> wrap)
      Transition to the given behavior and process numberOfMessages of the stashed messages. The messages will be processed in the same order they arrived.

      The purpose of this method, compared to unstashAll is to unstash a limited number of messages and then send a message to self before continuing unstashing more. That means that other new messages may arrive in-between and those must be stashed to keep the original order of messages. To differentiate between unstashed and new incoming messages the unstashed messages can be wrapped in another message with the wrap.

      If an exception is thrown by processing a message a proceeding messages and the message causing the exception have been removed from the StashBuffer, but unprocessed messages remain.

      It's allowed to stash messages while unstashing. Those newly added messages will not be processed by this call and have to be unstashed in another call.

      The behavior passed to unstash must not be unhandled.