Class PoolUtils.ErodingKeyedObjectPool<K,V>

java.lang.Object
org.datanucleus.store.rdbms.datasource.dbcp2.pool2.PoolUtils.ErodingKeyedObjectPool<K,V>
Type Parameters:
K - object pool key type
V - object pool value type
All Implemented Interfaces:
Closeable, AutoCloseable, KeyedObjectPool<K,V>
Direct Known Subclasses:
PoolUtils.ErodingPerKeyKeyedObjectPool
Enclosing class:
PoolUtils
private static class PoolUtils.ErodingKeyedObjectPool<K,V> extends Object implements KeyedObjectPool<K,V>
Decorates a keyed object pool, adding "eroding" behavior. Based on the configured erosion factor, objects returning to the pool may be invalidated instead of being added to idle capacity.
Since:
2.0

  • Field Details

  • Constructor Details

    • ErodingKeyedObjectPool

      public ErodingKeyedObjectPool(KeyedObjectPool<K,V> keyedPool, float factor)
      Creates an ErodingObjectPool wrapping the given pool using the specified erosion factor.
      Parameters:
      keyedPool - underlying pool
      factor - erosion factor - determines the frequency of erosion events
      See Also:

    • ErodingKeyedObjectPool

      protected ErodingKeyedObjectPool(KeyedObjectPool<K,V> keyedPool, PoolUtils.ErodingFactor erodingFactor)
      Creates an ErodingObjectPool wrapping the given pool using the specified erosion factor.
      Parameters:
      keyedPool - underlying pool - must not be null
      erodingFactor - erosion factor - determines the frequency of erosion events
      See Also:

  • Method Details

    • borrowObject

      public V borrowObject(K key) throws Exception, NoSuchElementException, IllegalStateException
      Obtains an instance from this pool for the specified key.

      Instances returned from this method will have been either newly created with makeObject or will be a previously idle object and have been activated with activateObject and then (optionally) validated with validateObject.

      By contract, clients must return the borrowed object using returnObject, invalidateObject, or a related method as defined in an implementation or sub-interface, using a key that is equivalent to the one used to borrow the instance in the first place.

      The behaviour of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations).

      Specified by:
      borrowObject in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key used to obtain the object
      Returns:
      an instance from this pool.
      Throws:
      Exception - when makeObject throws an exception
      NoSuchElementException - when the pool is exhausted and cannot or will not return another instance
      IllegalStateException - after close has been called on this pool

    • returnObject

      public void returnObject(K key, V obj) throws Exception
      Returns obj to the pool, unless erosion is triggered, in which case obj is invalidated. Erosion is triggered when there are idle instances in the pool associated with the given key and more than the configured erosion factor time has elapsed since the last returnObject activation.
      Specified by:
      returnObject in interface KeyedObjectPool<K,V>
      Parameters:
      key - key
      obj - object to return or invalidate
      Throws:
      Exception - if an instance cannot be returned to the pool
      See Also:

    • getErodingFactor

      protected PoolUtils.ErodingFactor getErodingFactor(K key)
      Returns the eroding factor for the given key
      Parameters:
      key - key
      Returns:
      eroding factor for the given keyed pool

    • invalidateObject

      public void invalidateObject(K key, V obj)
      Invalidates an object from the pool.

      By contract, obj must have been obtained using borrowObject or a related method as defined in an implementation or sub-interface using a key that is equivalent to the one used to borrow the Object in the first place.

      This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.

      Specified by:
      invalidateObject in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key used to obtain the object
      obj - a borrowed instance to be returned.

    • addObject

      public void addObject(K key) throws Exception, IllegalStateException, UnsupportedOperationException
      Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool. addObject is useful for "pre-loading" a pool with idle objects (Optional operation).
      Specified by:
      addObject in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key a new instance should be added to
      Throws:
      Exception - when KeyedPooledObjectFactory.makeObject(K) fails.
      IllegalStateException - after KeyedObjectPool.close() has been called on this pool.
      UnsupportedOperationException - when this pool cannot add new idle objects.

    • getNumIdle

      public int getNumIdle()
      Returns the total number of instances currently idle in this pool. Returns a negative value if this information is not available.
      Specified by:
      getNumIdle in interface KeyedObjectPool<K,V>
      Returns:
      the total number of instances currently idle in this pool.

    • getNumIdle

      public int getNumIdle(K key)
      Returns the number of instances corresponding to the given key currently idle in this pool. Returns a negative value if this information is not available.
      Specified by:
      getNumIdle in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key to query
      Returns:
      the number of instances corresponding to the given key currently idle in this pool.

    • getNumActive

      public int getNumActive()
      Returns the total number of instances currently borrowed from this pool but not yet returned. Returns a negative value if this information is not available.
      Specified by:
      getNumActive in interface KeyedObjectPool<K,V>
      Returns:
      the total number of instances currently borrowed from this pool but not yet returned.

    • getNumActive

      public int getNumActive(K key)
      Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key. Returns a negative value if this information is not available.
      Specified by:
      getNumActive in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key to query
      Returns:
      the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key.

    • clear

      public void clear() throws Exception, UnsupportedOperationException
      Clears the pool, removing all pooled instances (optional operation).
      Specified by:
      clear in interface KeyedObjectPool<K,V>
      Throws:
      Exception - if the pool cannot be cleared
      UnsupportedOperationException - when this implementation doesn't support the operation

    • clear

      public void clear(K key) throws Exception, UnsupportedOperationException
      Clears the specified pool, removing all pooled instances corresponding to the given key (optional operation).
      Specified by:
      clear in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key to clear
      Throws:
      Exception - if the key cannot be cleared
      UnsupportedOperationException - when this implementation doesn't support the operation

    • close

      public void close()
      Close this pool, and free any resources associated with it.

      Calling addObject or borrowObject after invoking this method on a pool will cause them to throw an IllegalStateException.

      Implementations should silently fail if not all resources can be freed.

      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface KeyedObjectPool<K,V>

    • getKeyedPool

      protected KeyedObjectPool<K,V> getKeyedPool()
      Returns the underlying pool
      Returns:
      the keyed pool that this ErodingKeyedObjectPool wraps

    • toString

      public String toString()
      Overrides:
      toString in class Object