Package org.apache.tomcat.dbcp.pool2
Interface KeyedPooledObjectFactory<K,V>
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- Type Parameters:
K- The type of keys managed by this factory.V- Type of element managed by this factory.
- All Known Implementing Classes:
PoolingConnection
public interface KeyedPooledObjectFactory<K,V>An interface defining life-cycle methods for instances to be served by aKeyedObjectPool.By contract, when an
KeyedObjectPooldelegates to aKeyedPooledObjectFactory,-
makeObject(K)is called whenever a new instance is needed. -
activateObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)is invoked on every instance that has beenpassivatedbefore it isborrowedfrom the pool. -
validateObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)may be invoked onactivatedinstances to make sure they can beborrowedfrom the pool.validateObjectmay also be used to test an instance beingreturnedto the pool before it ispassivated. It will only be invoked on an activated instance. -
passivateObjectis invoked on every instance when it is returned to the pool. -
destroyObjectis invoked on every instance when it is being "dropped" from the pool (whether due to the response fromvalidateObject, 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.
KeyedPooledObjectFactorymust be thread-safe. The only promise anKeyedObjectPoolmakes is that the same instance of an object will not be passed to more than one method of aKeyedPoolableObjectFactoryat a time.While clients of a
KeyedObjectPoolborrow and return instances of the underlying value type V, the factory methods act on instances ofPooledObject<V>. These are the object wrappers that pools use to track and maintain state informations about the objects that they manage.- Since:
- 2.0
- See Also:
KeyedObjectPool
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Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description voidactivateObject(K key, PooledObject<V> p)Reinitializes an instance to be returned by the pool.voiddestroyObject(K key, PooledObject<V> p)Destroys an instance no longer needed by the pool.default voiddestroyObject(K key, PooledObject<V> p, DestroyMode destroyMode)Destroys an instance no longer needed by the pool, using the providedDestroyMode.PooledObject<V>makeObject(K key)Creates an instance that can be served by the pool and wrap it in aPooledObjectto be managed by the pool.voidpassivateObject(K key, PooledObject<V> p)Uninitializes an instance to be returned to the idle object pool.booleanvalidateObject(K key, PooledObject<V> p)Ensures that the instance is safe to be returned by the pool.
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Method Detail
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activateObject
void activateObject(K key, PooledObject<V> p) throws Exception
Reinitializes an instance to be returned by the pool.- Parameters:
key- the key used when selecting the objectp- aPooledObjectwrapping the instance to be activated- Throws:
Exception- if there is a problem activatingobj, this exception may be swallowed by the pool.- See Also:
destroyObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)
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destroyObject
void destroyObject(K key, PooledObject<V> p) throws Exception
Destroys an instance no longer needed by the pool.It is important for implementations of this method to be aware that there is no guarantee about what state
objwill 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.
- Parameters:
key- the key used when selecting the instancep- aPooledObjectwrapping the instance to be destroyed- Throws:
Exception- should be avoided as it may be swallowed by the pool implementation.- See Also:
validateObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>),KeyedObjectPool.invalidateObject(K, V)
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destroyObject
default void destroyObject(K key, PooledObject<V> p, DestroyMode destroyMode) throws Exception
Destroys an instance no longer needed by the pool, using the providedDestroyMode.- Parameters:
key- the key used when selecting the instancep- aPooledObjectwrapping the instance to be destroyeddestroyMode- DestroyMode providing context to the factory- Throws:
Exception- should be avoided as it may be swallowed by the pool implementation.- Since:
- 2.9.0
- See Also:
validateObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>),KeyedObjectPool.invalidateObject(K, V),destroyObject(Object, PooledObject),DestroyMode
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makeObject
PooledObject<V> makeObject(K key) throws Exception
Creates an instance that can be served by the pool and wrap it in aPooledObjectto be managed by the pool.- Parameters:
key- the key used when constructing the object- Returns:
- a
PooledObjectwrapping 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.
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passivateObject
void passivateObject(K key, PooledObject<V> p) throws Exception
Uninitializes an instance to be returned to the idle object pool.- Parameters:
key- the key used when selecting the objectp- aPooledObjectwrapping the instance to be passivated- Throws:
Exception- if there is a problem passivatingobj, this exception may be swallowed by the pool.- See Also:
destroyObject(K, org.apache.tomcat.dbcp.pool2.PooledObject<V>)
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validateObject
boolean validateObject(K key, PooledObject<V> p)
Ensures that the instance is safe to be returned by the pool.- Parameters:
key- the key used when selecting the objectp- aPooledObjectwrapping the instance to be validated- Returns:
falseifobjis not valid and should be dropped from the pool,trueotherwise.
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