Class PoolUtils.ErodingObjectPool<T>
- java.lang.Object
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- org.apache.commons.pool.PoolUtils.ErodingObjectPool<T>
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- All Implemented Interfaces:
ObjectPool<T>
- Enclosing class:
- PoolUtils
private static class PoolUtils.ErodingObjectPool<T> extends java.lang.Object implements ObjectPool<T>
Decorates an object pool, adding "eroding" behavior. Based on the configurederosion factor
, objects returning to the pool may be invalidated instead of being added to idle capacity.
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Field Summary
Fields Modifier and Type Field Description private PoolUtils.ErodingFactor
factor
Erosion factorprivate ObjectPool<T>
pool
Underlying object pool
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Constructor Summary
Constructors Constructor Description ErodingObjectPool(ObjectPool<T> pool, float factor)
Create an ErodingObjectPool wrapping the given pool using the specified erosion factor.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
addObject()
Create an object using thefactory
or other implementation dependent mechanism, passivate it, and then place it in the idle object pool.T
borrowObject()
Obtains an instance from this pool.void
clear()
Clears any objects sitting idle in the pool, releasing any associated resources (optional operation).void
close()
Close this pool, and free any resources associated with it.int
getNumActive()
Return the number of instances currently borrowed from this pool (optional operation).int
getNumIdle()
Return the number of instances currently idle in this pool (optional operation).void
invalidateObject(T obj)
Invalidates an object from the pool.void
returnObject(T obj)
Returns obj to the pool, unless erosion is triggered, in which case obj is invalidated.void
setFactory(PoolableObjectFactory<T> factory)
Deprecated.to be removed in pool 2.0java.lang.String
toString()
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Field Detail
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pool
private final ObjectPool<T> pool
Underlying object pool
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factor
private final PoolUtils.ErodingFactor factor
Erosion factor
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Constructor Detail
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ErodingObjectPool
public ErodingObjectPool(ObjectPool<T> pool, float factor)
Create an ErodingObjectPool wrapping the given pool using the specified erosion factor.- Parameters:
pool
- underlying poolfactor
- erosion factor - determines the frequency of erosion events- See Also:
factor
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Method Detail
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borrowObject
public T borrowObject() throws java.lang.Exception, java.util.NoSuchElementException, java.lang.IllegalStateException
Obtains an instance from this pool.Instances returned from this method will have been either newly created with
makeObject
or will be a previously idle object and have been activated withactivateObject
and then validated withvalidateObject
.By contract, clients must return the borrowed instance using
returnObject
,invalidateObject
, or a related method as defined in an implementation or sub-interface.The behaviour of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations). Older versions of this method would return
null
to indicate exhaustion, newer versions are encouraged to throw aNoSuchElementException
.- Specified by:
borrowObject
in interfaceObjectPool<T>
- Returns:
- an instance from this pool.
- Throws:
java.lang.IllegalStateException
- afterclose
has been called on this pool.java.lang.Exception
- whenmakeObject
throws an exception.java.util.NoSuchElementException
- when the pool is exhausted and cannot or will not return another instance.
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returnObject
public void returnObject(T obj)
Returns obj to the pool, unless erosion is triggered, in which case obj is invalidated. Erosion is triggered when there are idle instances in the pool and more than theerosion factor
-determined time has elapsed since the last returnObject activation.- Specified by:
returnObject
in interfaceObjectPool<T>
- Parameters:
obj
- object to return or invalidate- See Also:
factor
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invalidateObject
public void invalidateObject(T obj)
Invalidates an object from the pool.
By contract,
obj
must have been obtained usingborrowObject
or a related method as defined in an implementation or sub-interface.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 interfaceObjectPool<T>
- Parameters:
obj
- aborrowed
instance to be disposed.
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addObject
public void addObject() throws java.lang.Exception, java.lang.IllegalStateException, java.lang.UnsupportedOperationException
Create an object using thefactory
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 interfaceObjectPool<T>
- Throws:
java.lang.Exception
- whenPoolableObjectFactory.makeObject()
fails.java.lang.IllegalStateException
- afterObjectPool.close()
has been called on this pool.java.lang.UnsupportedOperationException
- when this pool cannot add new idle objects.
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getNumIdle
public int getNumIdle() throws java.lang.UnsupportedOperationException
Return the number of instances currently idle in this pool (optional operation). This may be considered an approximation of the number of objects that can beborrowed
without creating any new instances. Returns a negative value if this information is not available.- Specified by:
getNumIdle
in interfaceObjectPool<T>
- Returns:
- the number of instances currently idle in this pool or a negative value if unsupported
- Throws:
java.lang.UnsupportedOperationException
- deprecated: if this implementation does not support the operation
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getNumActive
public int getNumActive() throws java.lang.UnsupportedOperationException
Return the number of instances currently borrowed from this pool (optional operation). Returns a negative value if this information is not available.- Specified by:
getNumActive
in interfaceObjectPool<T>
- Returns:
- the number of instances currently borrowed from this pool or a negative value if unsupported
- Throws:
java.lang.UnsupportedOperationException
- deprecated: if this implementation does not support the operation
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clear
public void clear() throws java.lang.Exception, java.lang.UnsupportedOperationException
Clears any objects sitting idle in the pool, releasing any associated resources (optional operation). Idle objects cleared must bedestroyed
.- Specified by:
clear
in interfaceObjectPool<T>
- Throws:
java.lang.UnsupportedOperationException
- if this implementation does not support the operationjava.lang.Exception
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close
public void close()
Close this pool, and free any resources associated with it.Calling
ObjectPool.addObject()
orObjectPool.borrowObject()
after invoking this method on a pool will cause them to throw anIllegalStateException
.- Specified by:
close
in interfaceObjectPool<T>
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setFactory
@Deprecated public void setFactory(PoolableObjectFactory<T> factory) throws java.lang.IllegalStateException, java.lang.UnsupportedOperationException
Deprecated.to be removed in pool 2.0Sets thefactory
this pool uses to create new instances (optional operation). Trying to change thefactory
after a pool has been used will frequently throw anUnsupportedOperationException
. It is up to the pool implementation to determine when it is acceptable to call this method.- Specified by:
setFactory
in interfaceObjectPool<T>
- Parameters:
factory
- thePoolableObjectFactory
used to create new instances.- Throws:
java.lang.IllegalStateException
- when the factory cannot be set at this timejava.lang.UnsupportedOperationException
- if this implementation does not support the operation
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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