org.apache.commons.pool2

接口 PooledObjectFactory<T>

类型参数:

T - Type of element managed in this factory.

所有已知实现类:

BasePooledObjectFactory, FtpClientFactory, JedisFactory

public interface PooledObjectFactory<T>

An interface defining life-cycle methods for instances to be served by an ObjectPool.

By contract, when an ObjectPool delegates to a PooledObjectFactory,

1. makeObject() is called whenever a new instance is needed.
2. activateObject(org.apache.commons.pool2.PooledObject<T>) is invoked on every instance that has been passivated before it is borrowed from the pool.
3. validateObject(org.apache.commons.pool2.PooledObject<T>) may be invoked on activated instances to make sure they can be borrowed from the pool. validateObject(org.apache.commons.pool2.PooledObject<T>) may also be used to test an instance being returned to the pool before it is passivated. It will only be invoked on an activated instance.
4. passivateObject(org.apache.commons.pool2.PooledObject<T>) is invoked on every instance when it is returned to the pool.
5. destroyObject(org.apache.commons.pool2.PooledObject<T>) is invoked on every instance when it is being "dropped" from the pool (whether due to the response from validateObject(org.apache.commons.pool2.PooledObject<T>), or for reasons specific to the pool implementation.) There is no guarantee that the instance being destroyed will be considered active, passive or in a generally consistent state.

PooledObjectFactory must be thread-safe. The only promise an ObjectPool makes is that the same instance of an object will not be passed to more than one method of a PoolableObjectFactory at a time.

While clients of a KeyedObjectPool borrow and return instances of the underlying value type V, the factory methods act on instances of PooledObject<V>. These are the object wrappers that pools use to track and maintain state information about the objects that they manage.

从以下版本开始:

2.0

另请参阅:

ObjectPool

方法概要

限定符和类型	方法和说明
void	activateObject(PooledObject<T> p) Reinitializes an instance to be returned by the pool.
void	destroyObject(PooledObject<T> p) Destroys an instance no longer needed by the pool, using the default (NORMAL) DestroyMode.
default void	destroyObject(PooledObject<T> p, DestroyMode mode) Destroys an instance no longer needed by the pool, using the provided DestroyMode.
PooledObject<T>	makeObject() Creates an instance that can be served by the pool and wrap it in a PooledObject to be managed by the pool.
void	passivateObject(PooledObject<T> p) Uninitializes an instance to be returned to the idle object pool.
boolean	validateObject(PooledObject<T> p) Ensures that the instance is safe to be returned by the pool.

方法详细资料

activateObject

void activateObject(PooledObject<T> p)
             throws java.lang.Exception

Reinitializes an instance to be returned by the pool.

参数:

p - a PooledObject wrapping the instance to be activated

抛出:

java.lang.Exception - if there is a problem activating obj, this exception may be swallowed by the pool.

另请参阅:

destroyObject(org.apache.commons.pool2.PooledObject<T>)

destroyObject

void destroyObject(PooledObject<T> p)
            throws java.lang.Exception

Destroys an instance no longer needed by the pool, using the default (NORMAL) DestroyMode.

It is important for implementations of this method to be aware that there is no guarantee about what state obj will be in and the implementation should be prepared to handle unexpected errors.

Also, an implementation must take in to consideration that instances lost to the garbage collector may never be destroyed.

参数:

p - a PooledObject wrapping the instance to be destroyed

抛出:

java.lang.Exception - should be avoided as it may be swallowed by the pool implementation.

另请参阅:

validateObject(org.apache.commons.pool2.PooledObject<T>), ObjectPool.invalidateObject(T)

destroyObject

default void destroyObject(PooledObject<T> p,
                           DestroyMode mode)
                    throws java.lang.Exception

Destroys an instance no longer needed by the pool, using the provided DestroyMode.

参数:

p - a PooledObject wrapping the instance to be destroyed

mode - DestroyMode providing context to the factory

抛出:

java.lang.Exception - should be avoided as it may be swallowed by the pool implementation.

从以下版本开始:

2.9.0

另请参阅:

validateObject(org.apache.commons.pool2.PooledObject<T>), ObjectPool.invalidateObject(T), destroyObject(PooledObject), DestroyMode

makeObject

PooledObject<T> makeObject()
                    throws java.lang.Exception

Creates an instance that can be served by the pool and wrap it in a PooledObject to be managed by the pool.

返回:

a PooledObject wrapping an instance that can be served by the pool

抛出:

java.lang.Exception - if there is a problem creating a new instance, this will be propagated to the code requesting an object.

passivateObject

void passivateObject(PooledObject<T> p)
              throws java.lang.Exception

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

参数:

p - a PooledObject wrapping the instance to be passivated

抛出:

java.lang.Exception - if there is a problem passivating obj, this exception may be swallowed by the pool.

另请参阅:

destroyObject(org.apache.commons.pool2.PooledObject<T>)

validateObject

boolean validateObject(PooledObject<T> p)

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

参数:

p - a PooledObject wrapping the instance to be validated

返回:

false if obj is not valid and should be dropped from the pool, true otherwise.