Package org.apache.tomcat.dbcp.pool2
Interface PooledObjectFactory<T>
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- Type Parameters:
T- Type of element managed in this factory.
- All Known Implementing Classes:
PoolableConnectionFactory,PoolableManagedConnectionFactory
public interface PooledObjectFactory<T>An interface defining life-cycle methods for instances to be served by anObjectPool.By contract, when an
ObjectPooldelegates to aPooledObjectFactory,-
makeObject()is called whenever a new instance is needed. -
activateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)is invoked on every instance that has beenpassivatedbefore it isborrowedfrom the pool. -
validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)may be invoked onactivatedinstances to make sure they can beborrowedfrom the pool.validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)may also be used to test an instance beingreturnedto the pool before it ispassivated. It will only be invoked on an activated instance. -
passivateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)is invoked on every instance when it is returned to the pool. -
destroyObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)is invoked on every instance when it is being "dropped" from the pool (whether due to the response fromvalidateObject(org.apache.tomcat.dbcp.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.
PooledObjectFactorymust be thread-safe. The only promise anObjectPoolmakes is that the same instance of an object will not be passed to more than one method of aPoolableObjectFactoryat a time.While clients of a
KeyedObjectPoolborrow and return instances of the underlying value typeV, the factory methods act on instances ofPooledObject<V>. These are the object wrappers that pools use to track and maintain state information about the objects that they manage.- Since:
- 2.0
- See Also:
ObjectPool
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Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description voidactivateObject(PooledObject<T> p)Reinitializes an instance to be returned by the pool.voiddestroyObject(PooledObject<T> p)Destroys an instance no longer needed by the pool, using the default (NORMAL) DestroyMode.default voiddestroyObject(PooledObject<T> p, DestroyMode destroyMode)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 aPooledObjectto be managed by the pool.voidpassivateObject(PooledObject<T> p)Uninitializes an instance to be returned to the idle object pool.booleanvalidateObject(PooledObject<T> 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(PooledObject<T> p) throws Exception
Reinitializes an instance to be returned by the pool.- Parameters:
p- 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(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
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destroyObject
void destroyObject(PooledObject<T> p) throws 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
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:
p- aPooledObjectwrapping the instance to be destroyed- Throws:
Exception- should be avoided as it may be swallowed by the pool implementation.- See Also:
validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>),ObjectPool.invalidateObject(T)
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destroyObject
default void destroyObject(PooledObject<T> p, DestroyMode destroyMode) throws Exception
Destroys an instance no longer needed by the pool, using the provided DestroyMode.- Parameters:
p- 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(org.apache.tomcat.dbcp.pool2.PooledObject<T>),ObjectPool.invalidateObject(T),destroyObject(PooledObject),DestroyMode
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makeObject
PooledObject<T> makeObject() throws Exception
Creates an instance that can be served by the pool and wrap it in aPooledObjectto be managed by the pool.- Returns:
- a
PooledObjectwrapping an instance that can be served by the pool, not null. - 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(PooledObject<T> p) throws Exception
Uninitializes an instance to be returned to the idle object pool.- Parameters:
p- 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(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
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validateObject
boolean validateObject(PooledObject<T> p)
Ensures that the instance is safe to be returned by the pool.- Parameters:
p- aPooledObjectwrapping the instance to be validated- Returns:
falseifobjis not valid and should be dropped from the pool,trueotherwise.
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