Package org.apache.commons.pool

Interface ObjectPool<T>

  • Type Parameters:
    T - the type of objects held in this pool
    All Known Implementing Classes:
    BaseObjectPool, GenericObjectPool, SoftReferenceObjectPool, StackObjectPool
    public interface ObjectPool<T>
    A pooling interface.

    ObjectPool defines a trivially simple pooling interface. The only required methods are borrowObject, returnObject and invalidateObject.

    Example of use: 

     Object obj = null;

 try {
     obj = pool.borrowObject();
     try {
         //...use the object...
     } catch(Exception e) {
         // invalidate the object
         pool.invalidateObject(obj);
         // do not return the object to the pool twice
         obj = null;
     } finally {
         // make sure the object is returned to the pool
         if(null != obj) {
             pool.returnObject(obj);
        }
     }
 } catch(Exception e) {
       // failed to borrow an object
 }

    See BaseObjectPool for a simple base implementation.

    Since:
    Pool 1.0
    Version:
    $Revision: 1222396 $ $Date: 2011-12-22 14:02:25 -0500 (Thu, 22 Dec 2011) $
    Author:
    Rodney Waldhoff, Sandy McArthur
    See Also:
    PoolableObjectFactory, ObjectPoolFactory, KeyedObjectPool, BaseObjectPool

    • Method Summary

      All Methods Instance Methods Abstract Methods Deprecated Methods 
      Modifier and Type Method Description
      void addObject()
      Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool.
      T borrowObject()
      Obtains an instance from this pool.
      void clear()
      Clears any objects sitting idle in the pool, releasing any associated resources (optional operation).
      void close()
      Close this pool, and free any resources associated with it.
      int getNumActive()
      Return the number of instances currently borrowed from this pool (optional operation).
      int getNumIdle()
      Return the number of instances currently idle in this pool (optional operation).
      void invalidateObject​(T obj)
      Invalidates an object from the pool.
      void returnObject​(T obj)
      Return an instance to the pool.
      void setFactory​(PoolableObjectFactory<T> factory)
      Deprecated.
      to be removed in pool 2.0