Class BaseObjectPool<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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- Type Parameters:
- T- Type of element pooled in this pool.
 - All Implemented Interfaces:
- java.io.Closeable,- java.lang.AutoCloseable,- ObjectPool<T>
 - Direct Known Subclasses:
- SoftReferenceObjectPool
 
 public abstract class BaseObjectPool<T> extends BaseObject implements ObjectPool<T> A simple base implementation ofObjectPool. Optional operations are implemented to either do nothing, return a value indicating it is unsupported or throwUnsupportedOperationException.This class is intended to be thread-safe. - Since:
- 2.0
 
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Constructor SummaryConstructors Constructor Description BaseObjectPool()
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Method SummaryAll Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidaddObject()Not supported in this base implementation.voidaddObjects(int count)CallsObjectPool.addObject()countnumber of times.protected voidassertOpen()Throws anIllegalStateExceptionwhen this pool has been closed.abstract TborrowObject()Obtains an instance from this pool.voidclear()Not supported in this base implementation.voidclose()Closes this pool, and free any resources associated with it.intgetNumActive()Not supported in this base implementation.intgetNumIdle()Not supported in this base implementation.abstract voidinvalidateObject(T obj)Invalidates an object from the pool.booleanisClosed()Has this pool instance been closed.abstract voidreturnObject(T obj)Returns an instance to the pool.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.BaseObjecttoString
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Methods inherited from class java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.apache.tomcat.dbcp.pool2.ObjectPoolinvalidateObject
 
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Method Detail- 
borrowObjectpublic abstract T borrowObject() throws java.lang.Exception Description copied from interface:ObjectPoolObtains an instance from this pool.Instances returned from this method will have been either newly created with PooledObjectFactory.makeObject()or will be a previously idle object and have been activated withPooledObjectFactory.activateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)and then validated withPooledObjectFactory.validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>).By contract, clients must return the borrowed instance using ObjectPool.returnObject(T),ObjectPool.invalidateObject(T), or a related method as defined in an implementation or sub-interface.The behavior of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations). - Specified by:
- borrowObjectin interface- ObjectPool<T>
- Returns:
- an instance from this pool.
- Throws:
- java.lang.IllegalStateException- after- closehas been called on this pool.
- java.lang.Exception- when- PooledObjectFactory.makeObject()throws an exception.
- java.util.NoSuchElementException- when the pool is exhausted and cannot or will not return another instance.
 
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returnObjectpublic abstract void returnObject(T obj) throws java.lang.Exception Description copied from interface:ObjectPoolReturns an instance to the pool. By contract,objmust have been obtained usingObjectPool.borrowObject()or a related method as defined in an implementation or sub-interface.- Specified by:
- returnObjectin interface- ObjectPool<T>
- Parameters:
- obj- a- borrowedinstance to be returned.
- Throws:
- java.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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invalidateObjectpublic abstract 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 interface- ObjectPool<T>
- Parameters:
- obj- a- borrowedinstance to be disposed.
- Throws:
- java.lang.Exception- if the instance cannot be invalidated
 
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getNumIdlepublic int getNumIdle() Not supported in this base implementation.- Specified by:
- getNumIdlein interface- ObjectPool<T>
- Returns:
- a negative value.
 
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getNumActivepublic int getNumActive() Not supported in this base implementation.- Specified by:
- getNumActivein interface- ObjectPool<T>
- Returns:
- a negative value.
 
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clearpublic void clear() throws java.lang.Exception, java.lang.UnsupportedOperationExceptionNot supported in this base implementation.- Specified by:
- clearin interface- ObjectPool<T>
- Throws:
- java.lang.UnsupportedOperationException- if the pool does not implement this method
- java.lang.Exception- if the pool cannot be cleared
 
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addObjectpublic void addObject() throws java.lang.Exception, java.lang.UnsupportedOperationExceptionNot supported in this base implementation. Subclasses should override this behavior.- Specified by:
- addObjectin interface- ObjectPool<T>
- Throws:
- java.lang.UnsupportedOperationException- if the pool does not implement this method
- java.lang.Exception- when- PooledObjectFactory.makeObject()fails.
- java.lang.IllegalStateException- after- ObjectPool.close()has been called on this pool.
 
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addObjectspublic void addObjects(int count) throws java.lang.ExceptionCallsObjectPool.addObject()countnumber of times.- Specified by:
- addObjectsin interface- ObjectPool<T>
- Parameters:
- count- the number of idle objects to add.
- Throws:
- java.lang.Exception- when- ObjectPool.addObject()fails.
- Since:
- 2.8.0
 
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closepublic void close() Closes 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.Implementations should silently fail if not all resources can be freed. This affects the behavior of isClosedandassertOpen.- Specified by:
- closein interface- java.lang.AutoCloseable
- Specified by:
- closein interface- java.io.Closeable
- Specified by:
- closein interface- ObjectPool<T>
 
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isClosedpublic final boolean isClosed() Has this pool instance been closed.- Returns:
- truewhen this pool has been closed.
 
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assertOpenprotected final void assertOpen() throws java.lang.IllegalStateExceptionThrows anIllegalStateExceptionwhen this pool has been closed.- Throws:
- java.lang.IllegalStateException- when this pool has been closed.
- See Also:
- isClosed()
 
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toStringAppendFieldsprotected 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 class- BaseObject
- Parameters:
- builder- Field names and values are appended to this object
 
 
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