Class PoolUtils.SynchronizedKeyedObjectPool<K,V>

java.lang.Object
org.datanucleus.store.rdbms.datasource.dbcp2.pool2.PoolUtils.SynchronizedKeyedObjectPool<K,V>
Type Parameters:
K - object pool key type
V - object pool value type
All Implemented Interfaces:
Closeable, AutoCloseable, KeyedObjectPool<K,V>
Enclosing class:
PoolUtils
private static final class PoolUtils.SynchronizedKeyedObjectPool<K,V> extends Object implements KeyedObjectPool<K,V>
A synchronized (thread-safe) KeyedObjectPool backed by the specified KeyedObjectPool.

Note: This should not be used on pool implementations that already provide proper synchronization such as the pools provided in the Commons Pool library. Wrapping a pool that waits for poolable objects to be returned before allowing another one to be borrowed with another layer of synchronization will cause liveliness issues or a deadlock.

Since:
2.0

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final KeyedObjectPool<K,V>
    keyedPool
    Underlying object pool
    private final ReentrantReadWriteLock
    readWriteLock
    Object whose monitor is used to synchronize methods on the wrapped pool.

  • Constructor Summary

    Constructors
    Constructor
    Description
    SynchronizedKeyedObjectPool(KeyedObjectPool<K,V> keyedPool)
    Creates a new SynchronizedKeyedObjectPool wrapping the given pool

  • 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.
    V
    borrowObject(K key)
    Obtains an instance from this pool for the specified key.
    void
    clear()
    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()
    Close this pool, and free any resources associated with it.
    int
    getNumActive()
    Returns the total number of instances currently borrowed from this pool but not yet returned.
    int
    getNumActive(K key)
    Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key.
    int
    getNumIdle()
    Returns the total number of instances currently idle in this pool.
    int
    getNumIdle(K key)
    Returns the number of instances corresponding to the given key currently idle in this pool.
    void
    invalidateObject(K key, V obj)
    Invalidates an object from the pool.
    void
    returnObject(K key, V obj)
    Return an instance to the pool.
    String
    toString()

    Methods inherited from class Object

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

    Methods inherited from interface KeyedObjectPool

    addObjects, addObjects

  • Field Details

    • readWriteLock

      private final ReentrantReadWriteLock readWriteLock
      Object whose monitor is used to synchronize methods on the wrapped pool.

    • keyedPool

      private final KeyedObjectPool<K,V> keyedPool
      Underlying object pool

  • Constructor Details

  • 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)
      Return an instance to 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 instance in the first place.
      Specified by:
      returnObject in interface KeyedObjectPool<K,V>
      Parameters:
      key - the key used to obtain the object
      obj - a borrowed instance to be returned.

    • 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(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(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.

    • 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.

    • 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.

    • 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>

    • toString

      public String toString()
      Overrides:
      toString in class Object