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:
Closeable,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 Summary
Constructors Constructor Description BaseObjectPool()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description voidaddObject()Not supported in this base implementation.protected voidassertOpen()Throws anIllegalStateExceptionwhen this pool has been closed.abstract TborrowObject()Borrows 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(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.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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Method Detail
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addObject
public void addObject() throws ExceptionNot supported in this base implementation. Subclasses should override this behavior.- Specified by:
addObjectin interfaceObjectPool<T>- Throws:
UnsupportedOperationException- if the pool does not implement this methodException- whenPooledObjectFactory.makeObject()fails.IllegalStateException- afterObjectPool.close()has been called on this pool.
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assertOpen
protected final void assertOpen() throws IllegalStateExceptionThrows anIllegalStateExceptionwhen this pool has been closed.- Throws:
IllegalStateException- when this pool has been closed.- See Also:
isClosed()
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borrowObject
public abstract T borrowObject() throws Exception
Description copied from interface:ObjectPoolBorrows 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 interfaceObjectPool<T>- Returns:
- an instance from this pool.
- Throws:
IllegalStateException- afterclosehas been called on this pool.Exception- whenPooledObjectFactory.makeObject()throws an exception.NoSuchElementException- when the pool is exhausted and cannot or will not return another instance.
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clear
public void clear() throws ExceptionNot supported in this base implementation.- Specified by:
clearin interfaceObjectPool<T>- Throws:
UnsupportedOperationException- if the pool does not implement this methodException- if the pool cannot be cleared
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close
public 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 interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Specified by:
closein interfaceObjectPool<T>
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getNumActive
public int getNumActive()
Not supported in this base implementation.- Specified by:
getNumActivein interfaceObjectPool<T>- Returns:
- a negative value.
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getNumIdle
public int getNumIdle()
Not supported in this base implementation.- Specified by:
getNumIdlein interfaceObjectPool<T>- Returns:
- a negative value.
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invalidateObject
public abstract void invalidateObject(T obj) throws 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>- Parameters:
obj- aborrowedinstance to be disposed.- Throws:
Exception- if the instance cannot be invalidated
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isClosed
public final boolean isClosed()
Has this pool instance been closed.- Returns:
truewhen this pool has been closed.
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returnObject
public abstract void returnObject(T obj) throws 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 interfaceObjectPool<T>- Parameters:
obj- aborrowedinstance to be returned.- Throws:
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.Exception- if an instance cannot be returned to the pool
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toStringAppendFields
protected void toStringAppendFields(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 classBaseObject- Parameters:
builder- Field names and values are appended to this object
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