Class SoftReferenceObjectPool<T>
- java.lang.Object
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- org.apache.tomcat.dbcp.pool2.BaseObject
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- org.apache.tomcat.dbcp.pool2.BaseObjectPool<T>
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- org.apache.tomcat.dbcp.pool2.impl.SoftReferenceObjectPool<T>
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- Type Parameters:
T- Type of element pooled in this pool.
- All Implemented Interfaces:
java.io.Closeable,java.lang.AutoCloseable,ObjectPool<T>
public class SoftReferenceObjectPool<T> extends BaseObjectPool<T>
- Since:
- 2.0
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Constructor Summary
Constructors Constructor Description SoftReferenceObjectPool(PooledObjectFactory<T> factory)Constructs aSoftReferenceObjectPoolwith the specified factory.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidaddObject()Creates an object, and places it into the pool. addObject() is useful for "pre-loading" a pool with idle objects.TborrowObject()Borrows an object from the pool.voidclear()Clears any objects sitting idle in the pool.voidclose()Closes this pool, and frees any resources associated with it.PooledObjectFactory<T>getFactory()Gets thePooledObjectFactoryused by this pool to create and manage object instances.intgetNumActive()Gets the number of instances currently borrowed from this pool.intgetNumIdle()Gets an approximation not less than the of the number of idle instances in the pool.voidinvalidateObject(T obj)Invalidates an object from the pool.voidreturnObject(T obj)Returns an instance to the pool after successful validation and passivation.protected voidtoStringAppendFields(java.lang.StringBuilder builder)Used by sub-classes to include the fields defined by the sub-class in theBaseObject.toString()output.-
Methods inherited from class org.apache.tomcat.dbcp.pool2.BaseObjectPool
assertOpen, isClosed
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Methods inherited from class org.apache.tomcat.dbcp.pool2.BaseObject
toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.tomcat.dbcp.pool2.ObjectPool
addObjects, invalidateObject
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Constructor Detail
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SoftReferenceObjectPool
public SoftReferenceObjectPool(PooledObjectFactory<T> factory)
Constructs aSoftReferenceObjectPoolwith the specified factory.- Parameters:
factory- object factory to use.
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Method Detail
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addObject
public void addObject() throws java.lang.ExceptionCreates an object, and places it into the pool. addObject() is useful for "pre-loading" a pool with idle objects.Before being added to the pool, the newly created instance is
validatedandpassivated. If validation fails, the new instance isdestroyed. Exceptions generated by the factorymakeObjectorpassivateare propagated to the caller. Exceptions destroying instances are silently swallowed.- Specified by:
addObjectin interfaceObjectPool<T>- Overrides:
addObjectin classBaseObjectPool<T>- Throws:
java.lang.IllegalStateException- if invoked on aclosedpooljava.lang.Exception- when thefactoryhas a problem creating or passivating an object.
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borrowObject
public T borrowObject() throws java.lang.Exception
Borrows an object from the pool. If there are no idle instances available in the pool, the configured factory'sPooledObjectFactory.makeObject()method is invoked to create a new instance.All instances are
activatedandvalidatedbefore being returned by this method. If validation fails or an exception occurs activating or validating an idle instance, the failing instance isdestroyedand another instance is retrieved from the pool, validated and activated. This process continues until either the pool is empty or an instance passes validation. If the pool is empty on activation or it does not contain any valid instances, the factory'smakeObjectmethod is used to create a new instance. If the created instance either raises an exception on activation or fails validation,NoSuchElementExceptionis thrown. Exceptions thrown byMakeObjectare propagated to the caller; but other thanThreadDeathorVirtualMachineError, exceptions generated by activation, validation or destroy methods are swallowed silently.- Specified by:
borrowObjectin interfaceObjectPool<T>- Specified by:
borrowObjectin classBaseObjectPool<T>- Returns:
- a valid, activated object instance
- Throws:
java.util.NoSuchElementException- if a valid object cannot be providedjava.lang.IllegalStateException- if invoked on aclosedpooljava.lang.Exception- if an exception occurs creating a new instance
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clear
public void clear()
Clears any objects sitting idle in the pool.- Specified by:
clearin interfaceObjectPool<T>- Overrides:
clearin classBaseObjectPool<T>
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close
public void close()
Closes this pool, and frees any resources associated with it. Invokesclear()to destroy and remove instances in the pool.Calling
addObject()orborrowObject()after invoking this method on a pool will cause them to throw anIllegalStateException.- Specified by:
closein interfacejava.lang.AutoCloseable- Specified by:
closein interfacejava.io.Closeable- Specified by:
closein interfaceObjectPool<T>- Overrides:
closein classBaseObjectPool<T>
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getFactory
public PooledObjectFactory<T> getFactory()
Gets thePooledObjectFactoryused by this pool to create and manage object instances.- Returns:
- the factory
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getNumActive
public int getNumActive()
Gets the number of instances currently borrowed from this pool.- Specified by:
getNumActivein interfaceObjectPool<T>- Overrides:
getNumActivein classBaseObjectPool<T>- Returns:
- the number of instances currently borrowed from this pool
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getNumIdle
public int getNumIdle()
Gets an approximation not less than the of the number of idle instances in the pool.- Specified by:
getNumIdlein interfaceObjectPool<T>- Overrides:
getNumIdlein classBaseObjectPool<T>- Returns:
- estimated number of idle instances in the pool
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invalidateObject
public void invalidateObject(T obj) throws java.lang.Exception
Description copied from interface:ObjectPoolInvalidates an object from the pool.By contract,
objmust have been obtained usingObjectPool.borrowObject()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:
invalidateObjectin interfaceObjectPool<T>- Specified by:
invalidateObjectin classBaseObjectPool<T>- Parameters:
obj- aborrowedinstance to be disposed.- Throws:
java.lang.Exception- if the instance cannot be invalidated
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returnObject
public void returnObject(T obj) throws java.lang.Exception
Returns an instance to the pool after successful validation and passivation. The returning instance is destroyed if any of the following are true:- the pool is closed
validationfailspassivationthrows an exception
- Specified by:
returnObjectin interfaceObjectPool<T>- Specified by:
returnObjectin classBaseObjectPool<T>- Parameters:
obj- instance to return to the pool- Throws:
java.lang.IllegalArgumentException- if obj is not currently part of this pooljava.lang.IllegalStateException- if an attempt is made to return an object to the pool that is in any state other than allocated (i.e. borrowed). Attempting to return an object more than once or attempting to return an object that was never borrowed from the pool will trigger this exception.java.lang.Exception- if an instance cannot be returned to the pool
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toStringAppendFields
protected void toStringAppendFields(java.lang.StringBuilder builder)
Description copied from class:BaseObjectUsed by sub-classes to include the fields defined by the sub-class in theBaseObject.toString()output.- Overrides:
toStringAppendFieldsin classBaseObjectPool<T>- Parameters:
builder- Field names and values are appended to this object
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