jrunx.pool
Class ObjectPool

java.lang.Object
  |
  +--jrunx.pool.ObjectPool

All Implemented Interfaces:

Pool, java.io.Serializable

Direct Known Subclasses:

ConnectionPool

public abstract class ObjectPool

extends java.lang.Object

implements Pool

ObjectPool provides a mechanism for pooling objects and resources. It must be subclassed to create specific pools; GenericPool and JDBCPool are examples of such subclasses.

Author:

PS Neville

See Also:

Serialized Form

Field Summary

protected int	count
protected boolean	createdLogger
protected boolean	isDefault
protected java.lang.Thread	lifeguard
protected java.util.Hashtable	locked
Logger	logger
protected PoolMetaData	metadata
protected java.lang.Thread	skimmer
protected java.util.Hashtable	unlocked

Constructor Summary

ObjectPool(PoolMetaData metad)

Method Summary

protected void	checkIn(java.lang.Object o) Checks an object back into the pool.
protected java.lang.Object	checkOut() Checkout cycles through the available objects and returns the first valid object it finds.
protected void	checkTimeout() Determine whether locked objects have timed out and should be checked back in.
protected void	cleanUp() Remove timed-out objects from the pool, called by PoolSkimmerThread.
void	closeAllResources() Close all resources in the pool.
protected abstract java.lang.Object	create()
protected void	debugMetrics()
protected void	expire(java.lang.Object o) Default expiration invokes PooledObject.closeAllResources()
void	finalize()
Logger	getLogger()
java.lang.String	getPoolname()
protected boolean	holdingLock(java.lang.Object o) Override for custom pool lock behavior
void	init()
void	initLogger()
boolean	isDefault()
int	numCheckedInObjects()
int	numCheckedOutObjects()
int	numTotalObjects()
java.lang.Object	requestObject() Subclasses will usually want to override this method.
void	returnObject(java.lang.Object o) Subclasses will usually want to override this method, at least for type safety.
void	setIsDefault(boolean b)
void	updateLocked(PooledObject o)
protected abstract boolean	validate(java.lang.Object o)

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

metadata

protected PoolMetaData metadata

count

protected int count

locked

protected java.util.Hashtable locked

unlocked

protected java.util.Hashtable unlocked

skimmer

protected java.lang.Thread skimmer

lifeguard

protected java.lang.Thread lifeguard

createdLogger

protected boolean createdLogger

logger

public Logger logger

isDefault

protected boolean isDefault

Constructor Detail

ObjectPool

public ObjectPool(PoolMetaData metad)

Method Detail

init

public void init()
          throws java.lang.Exception

create

protected abstract java.lang.Object create()
                                    throws java.lang.Exception

validate

protected abstract boolean validate(java.lang.Object o)

holdingLock

protected boolean holdingLock(java.lang.Object o)

Override for custom pool lock behavior

expire

protected void expire(java.lang.Object o)

Default expiration invokes PooledObject.closeAllResources()

getPoolname

public java.lang.String getPoolname()

Specified by:

getPoolname in interface Pool

isDefault

public boolean isDefault()

setIsDefault

public void setIsDefault(boolean b)

requestObject

public java.lang.Object requestObject()

Subclasses will usually want to override this method.

Specified by:

requestObject in interface Pool

returnObject

public void returnObject(java.lang.Object o)

Subclasses will usually want to override this method, at least for type safety.

Specified by:

returnObject in interface Pool

numTotalObjects

public int numTotalObjects()

Returns:

int The total number of objects in the pool, both locked and unlocked.

numCheckedOutObjects

public int numCheckedOutObjects()

Returns:

int The number of objects currently available.

numCheckedInObjects

public int numCheckedInObjects()

Returns:

int The number of objects currently checked out.

checkOut

protected java.lang.Object checkOut()
                             throws java.lang.Exception

Checkout cycles through the available objects and returns the first valid object it finds. if there are no valid objects, checkOut will create one, unless the client specified amount of objects have already been created, and then it will block until it finds an appropriate object

checkIn

protected void checkIn(java.lang.Object o)

Checks an object back into the pool.

updateLocked

public void updateLocked(PooledObject o)

cleanUp

protected void cleanUp()

Remove timed-out objects from the pool, called by PoolSkimmerThread. Checks the unlocked objects for expired members, and shrinks the pool according to the shrinkBy value, ensuring that it keeps at least the minimumSize number of objects available.

checkTimeout

protected void checkTimeout()

Determine whether locked objects have timed out and should be checked back in. Called by LifeGuardThread.

closeAllResources

public void closeAllResources()

Close all resources in the pool.

finalize

public void finalize()

Overrides:

finalize in class java.lang.Object

debugMetrics

protected void debugMetrics()

initLogger

public void initLogger()

getLogger

public Logger getLogger()