BaseKeyedPooledObjectFactory (Apache Tomcat 8.5.57 API Documentation)

org.apache.tomcat.dbcp.pool2

## Class BaseKeyedPooledObjectFactory<K,V>

- java.lang.Object
- - org.apache.tomcat.dbcp.pool2.BaseObject
  - - org.apache.tomcat.dbcp.pool2.BaseKeyedPooledObjectFactory<K,V>

- Type Parameters:
    `K` - The type of keys managed by this factory.
    `V` - Type of element managed by this factory.
  All Implemented Interfaces:
    KeyedPooledObjectFactory<K,V>

      public abstract class BaseKeyedPooledObjectFactory<K,V>
      extends BaseObject
      implements KeyedPooledObjectFactory<K,V>

  A base implementation of `KeyedPooledObjectFactory`.

  All operations defined here are essentially no-op's.

  This class is immutable, and therefore thread-safe.

  Since:
    2.0
  See Also:
    `KeyedPooledObjectFactory`

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `BaseKeyedPooledObjectFactory()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `activateObject(K key, PooledObject<V> p)` Reinitialize an instance to be returned by the pool.
    `abstract V` | `create(K key)` Create an instance that can be served by the pool.
    `void` | `destroyObject(K key, PooledObject<V> p)` Destroy an instance no longer needed by the pool.
    `PooledObject<V>` | `makeObject(K key)` Create an instance that can be served by the pool and wrap it in a `PooledObject` to be managed by the pool.
    `void` | `passivateObject(K key, PooledObject<V> p)` Uninitialize an instance to be returned to the idle object pool.
    `boolean` | `validateObject(K key, PooledObject<V> p)` Ensures that the instance is safe to be returned by the pool.
    `abstract PooledObject<V>` | `wrap(V value)` Wrap the provided instance with an implementation of `PooledObject`.

    - ### Methods inherited from class org.apache.tomcat.dbcp.pool2.BaseObject

      `toString, toStringAppendFields`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### BaseKeyedPooledObjectFactory

          public BaseKeyedPooledObjectFactory()

  - ### Method Detail

    - #### create

          public abstract V create(K key)
                            throws Exception

      Create an instance that can be served by the pool.
      Parameters:
        `key` - the key used when constructing the object
      Returns:
        an instance that can be served by the pool
      Throws:
        `Exception` - if there is a problem creating a new instance, this will be propagated to the code requesting an object.

    - #### wrap

          public abstract PooledObject<V> wrap(V value)

      Wrap the provided instance with an implementation of `PooledObject`.
      Parameters:
        `value` - the instance to wrap
      Returns:
        The provided instance, wrapped by a `PooledObject`

    - #### makeObject

          public PooledObject<V> makeObject(K key)
                                     throws Exception

      Description copied from interface: `KeyedPooledObjectFactory`
      Create an instance that can be served by the pool and wrap it in a `PooledObject` to be managed by the pool.
      Specified by:
        `makeObject` in interface `KeyedPooledObjectFactory<K,V>`
      Parameters:
        `key` - the key used when constructing the object
      Returns:
        a `PooledObject` wrapping an instance that can be served by the pool.
      Throws:
        `Exception` - if there is a problem creating a new instance, this will be propagated to the code requesting an object.

    - #### destroyObject

          public void destroyObject(K key,
                           PooledObject<V> p)
                             throws Exception

      Destroy an instance no longer needed by the pool.

      The default implementation is a no-op.

      Specified by:
        `destroyObject` in interface `KeyedPooledObjectFactory<K,V>`
      Parameters:
        `key` - the key used when selecting the instance
        `p` - a `PooledObject` wrapping the instance to be destroyed
      Throws:
        `Exception` - should be avoided as it may be swallowed by the pool implementation.
      See Also:
        `KeyedPooledObjectFactory.validateObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)`, `KeyedObjectPool.invalidateObject(K, V)`

    - #### validateObject

          public boolean validateObject(K key,
                               PooledObject<V> p)

      Ensures that the instance is safe to be returned by the pool.

      The default implementation always returns `true`.

      Specified by:
        `validateObject` in interface `KeyedPooledObjectFactory<K,V>`
      Parameters:
        `key` - the key used when selecting the object
        `p` - a `PooledObject` wrapping the instance to be validated
      Returns:
        always `true` in the default implementation

    - #### activateObject

          public void activateObject(K key,
                            PooledObject<V> p)
                              throws Exception

      Reinitialize an instance to be returned by the pool.

      The default implementation is a no-op.

      Specified by:
        `activateObject` in interface `KeyedPooledObjectFactory<K,V>`
      Parameters:
        `key` - the key used when selecting the object
        `p` - a `PooledObject` wrapping the instance to be activated
      Throws:
        `Exception` - if there is a problem activating `obj`, this exception may be swallowed by the pool.
      See Also:
        `KeyedPooledObjectFactory.destroyObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)`

    - #### passivateObject

          public void passivateObject(K key,
                             PooledObject<V> p)
                               throws Exception

      Uninitialize an instance to be returned to the idle object pool.

      The default implementation is a no-op.

      Specified by:
        `passivateObject` in interface `KeyedPooledObjectFactory<K,V>`
      Parameters:
        `key` - the key used when selecting the object
        `p` - a `PooledObject` wrapping the instance to be passivated
      Throws:
        `Exception` - if there is a problem passivating `obj`, this exception may be swallowed by the pool.
      See Also:
        `KeyedPooledObjectFactory.destroyObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)`

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