Class PoolUtils.ErodingKeyedObjectPool<K,V>

java.lang.Object
org.apache.commons.pool.PoolUtils.ErodingKeyedObjectPool<K,V>
All Implemented Interfaces:
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
invalid reference
erosion factor
, objects returning to the pool may be invalidated instead of being added to idle capacity.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    Erosion factor
    private final KeyedObjectPool<K,V>
    Underlying pool
  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
     
    ErodingKeyedObjectPool(KeyedObjectPool<K,V> keyedPool, float factor)
    Create an ErodingObjectPool wrapping the given pool using the specified erosion factor.
    protected
    Create an ErodingObjectPool wrapping the given pool using the specified erosion factor.
  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addObject(K key)
    Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool.
    Obtains an instance from this pool for the specified key.
    void
    Clears the pool, removing all pooled instances (optional operation).
    void
    clear(K key)
    Clears the specified pool, removing all pooled instances corresponding to the given key (optional operation).
    void
    Close this pool, and free any resources associated with it.
    Returns the eroding factor for the given key
    protected KeyedObjectPool<K,V>
    Returns the underlying pool
    int
    Returns the total number of instances current borrowed from this pool but not yet returned (optional operation).
    int
    Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key (optional operation).
    int
    Returns the total number of instances currently idle in this pool (optional operation).
    int
    Returns the number of instances corresponding to the given key currently idle in this pool (optional operation).
    void
    invalidateObject(K key, V obj)
    Invalidates an object from the pool.
    protected int
    numIdle(K key)
    Returns the total number of instances currently idle in this pool (optional operation).
    void
    returnObject(K key, V obj)
    Returns obj to the pool, unless erosion is triggered, in which case obj is invalidated.
    void
    Deprecated.
    to be removed in pool 2.0

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
  • Field Details

  • Constructor Details

    • ErodingKeyedObjectPool

      public ErodingKeyedObjectPool(KeyedObjectPool<K,V> keyedPool, float factor)
      Create 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)
      Create 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:
      • invalid reference
        #factor
  • 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 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). Older versions of this method would return null to indicate exhaustion, newer versions are encouraged to throw a NoSuchElementException.

      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
      See Also:
    • numIdle

      protected int numIdle(K key)
      Returns the total number of instances currently idle in this pool (optional operation). Returns a negative value if this information is not available.
      Parameters:
      key - ignored
      Returns:
      the total number of instances currently idle in this pool or a negative value if unsupported
      Throws:
      UnsupportedOperationException - deprecated: when this implementation doesn't support the operation
    • 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 KeyedPoolableObjectFactory.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() throws UnsupportedOperationException
      Returns the total number of instances currently idle in this pool (optional operation). 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 or a negative value if unsupported
      Throws:
      UnsupportedOperationException - deprecated: when this implementation doesn't support the operation
    • getNumIdle

      public int getNumIdle(K key) throws UnsupportedOperationException
      Returns the number of instances corresponding to the given key currently idle in this pool (optional operation). 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 or a negative value if unsupported
      Throws:
      UnsupportedOperationException - deprecated: when this implementation doesn't support the operation
    • getNumActive

      public int getNumActive() throws UnsupportedOperationException
      Returns the total number of instances current borrowed from this pool but not yet returned (optional operation). 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 or a negative value if unsupported
      Throws:
      UnsupportedOperationException - deprecated: when this implementation doesn't support the operation
    • getNumActive

      public int getNumActive(K key) throws UnsupportedOperationException
      Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key (optional operation). 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 corresponding to the given key currently borrowed in this pool or a negative value if unsupported
      Throws:
      UnsupportedOperationException - deprecated: when this implementation doesn't support the operation
    • clear

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

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

      Specified by:
      close in interface KeyedObjectPool<K,V>
    • setFactory

      Deprecated.
      to be removed in pool 2.0
      Sets the factory the pool uses to create new instances (optional operation). Trying to change the factory after a pool has been used will frequently throw an UnsupportedOperationException. It is up to the pool implementation to determine when it is acceptable to call this method.
      Specified by:
      setFactory in interface KeyedObjectPool<K,V>
      Parameters:
      factory - the KeyedPoolableObjectFactory used to create new instances.
      Throws:
      IllegalStateException - when the factory cannot be set at this time
      UnsupportedOperationException - when this implementation doesn't support the operation
    • 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