Module lettuce.core
Package io.lettuce.core.support

Class BoundedAsyncPool<T>

java.lang.Object
io.lettuce.core.support.BasePool
io.lettuce.core.support.BoundedAsyncPool<T>
All Implemented Interfaces:
AsyncCloseable, AsyncPool<T>, Closeable, AutoCloseable
public class BoundedAsyncPool<T>
extends BasePool
implements AsyncPool<T>
Bounded asynchronous object pool. This object pool allows pre-warming with idle objects upon construction. The pool is stateful and requires cleanup once it's no longer in use.

Object pool bounds are maintained on a best-effort basis as bounds are maintained upon object request whereas the actual object creation might finish at a later time. You might see temporarily slight differences in object usage vs. pool count due to asynchronous processing vs. protecting the pool from exceed its bounds.

Since:
5.1
Author:
Mark Paluch
See Also:
BoundedPoolConfig, AsyncObjectFactory

  • Field Details

  • Constructor Details

  • Method Details

    • create

      public static <T> CompletionStage<BoundedAsyncPool<T>> create​(AsyncObjectFactory<T> factory, BoundedPoolConfig poolConfig)
      Create and initialize BoundedAsyncPool asynchronously.
      Type Parameters:
      T - object type that is managed by the pool.
      Parameters:
      factory - must not be null.
      poolConfig - must not be null.
      Returns:
      a CompletionStage that completes with the BoundedAsyncPool when created and pre-initialized successfully. Completes exceptionally if the pool initialization failed.
      Since:
      5.3.3

    • acquire

      public CompletableFuture<T> acquire()
      Description copied from interface: AsyncPool
      Acquire an object from this AsyncPool. The returned CompletableFuture is notified once the acquire is successful and failed otherwise. Behavior upon acquiring objects from an exhausted pool depends on the actual pool implementation whether requests are rejected immediately (exceptional completion with NoSuchElementException) or delayed after exceeding a particular timeout ( TimeoutException). It's required that an acquired object is always released to the pool again once the object is no longer in use..
      Specified by:
      acquire in interface AsyncPool<T>

    • release

      public CompletableFuture<Void> release​(T object)
      Description copied from interface: AsyncPool
      Release an object back to this AsyncPool. The returned CompletableFuture is notified once the release is successful and failed otherwise. When failed the object will automatically disposed.
      Specified by:
      release in interface AsyncPool<T>
      Parameters:
      object - the object to be released. The object must have been acquired from this pool.

    • clear

      public void clear()
      Description copied from interface: AsyncPool
      Clear the pool.
      Specified by:
      clear in interface AsyncPool<T>

    • clearAsync

      public CompletableFuture<Void> clearAsync()
      Description copied from interface: AsyncPool
      Clear the pool.
      Specified by:
      clearAsync in interface AsyncPool<T>

    • close

      public void close()
      Specified by:
      close in interface AsyncPool<T>
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable

    • closeAsync

      public CompletableFuture<Void> closeAsync()
      Description copied from interface: AsyncCloseable
      Requests to close this object and releases any system resources associated with it. If the object is already closed then invoking this method has no effect.

      Calls to this method return a CompletableFuture that is notified with the outcome of the close request.

      Specified by:
      closeAsync in interface AsyncCloseable
      Specified by:
      closeAsync in interface AsyncPool<T>

    • getMaxTotal

      public int getMaxTotal()
      Returns the maximum number of objects that can be allocated by the pool (checked out to clients, or idle awaiting checkout) at a given time. When negative, there is no limit to the number of objects that can be managed by the pool at one time.
      Returns:
      the cap on the total number of object instances managed by the pool.
      See Also:
      BoundedPoolConfig.getMaxTotal()

    • getMaxIdle

      public int getMaxIdle()
      Returns the cap on the number of "idle" instances in the pool. If maxIdle is set too low on heavily loaded systems it is possible you will see objects being destroyed and almost immediately new objects being created. This is a result of the active threads momentarily returning objects faster than they are requesting them them, causing the number of idle objects to rise above maxIdle. The best value for maxIdle for heavily loaded system will vary but the default is a good starting point.
      Returns:
      the maximum number of "idle" instances that can be held in the pool.
      See Also:
      BoundedPoolConfig.getMaxIdle()

    • getMinIdle

      public int getMinIdle()
      Returns the target for the minimum number of idle objects to maintain in the pool. If this is the case, an attempt is made to ensure that the pool has the required minimum number of instances during idle object eviction runs.

      If the configured value of minIdle is greater than the configured value for maxIdle then the value of maxIdle will be used instead.

      Returns:
      The minimum number of objects.
      See Also:
      BoundedPoolConfig.getMinIdle()

    • getIdle

      public int getIdle()

    • getObjectCount

      public int getObjectCount()

    • getCreationInProgress

      public int getCreationInProgress()