Package org.apache.hadoop.fs.impl.prefetch

Class ResourcePool<T>

java.lang.Object
org.apache.hadoop.fs.impl.prefetch.ResourcePool<T>
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
BoundedResourcePool
public abstract class ResourcePool<T> extends Object implements Closeable
Manages a fixed pool of resources. Avoids creating a new resource if a previously created instance is already available.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ResourcePool()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract T
    acquire()
    Acquires a resource blocking if necessary until one becomes available.
    void
    close()
     
    protected void
    close(T item)
    Derived classes may implement a way to cleanup each item.
    protected abstract T
    createNew()
    Derived classes must implement a way to create an instance of a resource.
    abstract void
    release(T item)
    Releases a previously acquired resource.
    abstract T
    tryAcquire()
    Acquires a resource blocking if one is immediately available.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • ResourcePool

      public ResourcePool()

  • Method Details

    • acquire

      public abstract T acquire()
      Acquires a resource blocking if necessary until one becomes available.
      Returns:
      the acquired resource instance.

    • tryAcquire

      public abstract T tryAcquire()
      Acquires a resource blocking if one is immediately available. Otherwise returns null.
      Returns:
      the acquired resource instance (if immediately available) or null.

    • release

      public abstract void release(T item)
      Releases a previously acquired resource.
      Parameters:
      item - the resource to release.

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable

    • close

      protected void close(T item)
      Derived classes may implement a way to cleanup each item.
      Parameters:
      item - the resource to close.

    • createNew

      protected abstract T createNew()
      Derived classes must implement a way to create an instance of a resource.
      Returns:
      the created instance.