com.sun.ejb.containers.util.pool
Class AbstractPool

java.lang.Object
  com.sun.ejb.containers.util.pool.AbstractPool

All Implemented Interfaces:

Pool, EJBPoolStatsProvider, StatsProvider

Direct Known Subclasses:

BoundedPool, NonBlockingPool

public abstract class AbstractPool
extends Object
implements Pool, EJBPoolStatsProvider

Abstract pool provides the basic implementation of an object pool. The implementation uses a linked list to maintain a list of (available) objects. If the pool is empty it simply creates one using the ObjectFactory instance. Subclasses can change this behaviour by overriding getObject(...) and returnObject(....) methods. This class provides basic support for synchronization, event notification, pool shutdown and pool object recycling. It also does some very basic bookkeeping like the number of objects created, number of threads waiting for object.

Subclasses can make use of these book-keeping data to provide complex pooling mechanism like LRU / MRU / Random. Also, note that AbstractPool does not have a notion of pool limit. It is upto to the derived classes to implement these features.

Field Summary

protected static Logger	_logger
protected String	appName
protected long	beanId
protected String	configData
protected ClassLoader	containerClassLoader
protected int	createdCount
protected int	destroyedCount
protected String	ejbName
protected ObjectFactory	factory
protected int	idleTimeoutInSeconds
protected ArrayList	list
protected int	maxPoolSize
protected long	maxWaitTimeInMillis
protected String	modName
protected String	poolName
protected EjbPoolProbeProvider	poolProbeNotifier
protected int	poolReturned
protected int	poolSuccess
protected int	resizeQuantity
protected int	steadyPoolSize
protected int	waitCount

Constructor Summary

protected	AbstractPool()
protected	AbstractPool(ObjectFactory factory, long beanId, int steadyPoolSize, int resizeQuantity, int maxPoolsize, long maxWaitTimeInMillis, int idleTimeoutInSeconds, ClassLoader loader)

Method Summary

void	appendStats(StringBuffer sbuf)
void	close() Close the pool
void	destroyObject(Object object) Destroys an Object.
String	getAllAttrValues()
String	getAllMonitoredAttrbuteValues()
int	getCreatedCount()
int	getDestroyedCount()
int	getIdleTimeoutInSeconds()
int	getJmsMaxMessagesLoad()
int	getMaxPoolSize()
long	getMaxWaitTimeInMillis()
int	getNumBeansInPool()
int	getNumThreadsWaiting()
Object	getObject(boolean canWait, Object param) Get an object.
Object	getObject(long maxWaitTime, Object param)
Object	getObject(Object param) Get an object from the pool within the specified time.
int	getPoolSuccess()
int	getResizeQuantity()
int	getSize()
int	getSteadyPoolSize()
int	getTotalBeansCreated()
int	getTotalBeansDestroyed()
int	getWaitCount()
protected void	initializePool(ObjectFactory factory, long beanId, int steadyPoolSize, int resizeQuantity, int maxPoolsize, long maxWaitTimeInMillis, int idleTimeoutInSeconds, ClassLoader loader)
protected void	preload(int count) Preload the pool with objects.
protected void	remove(int count)
protected abstract void	removeIdleObjects()
void	returnObject(Object object) Return an object back to the pool.
void	setConfigData(String configData)
void	setContainerClassLoader(ClassLoader loader)
void	setInfo(String appName, String modName, String ejbName)
protected void	unregisterProbeProvider()

Methods inherited from class java.lang.Object

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

Field Detail

_logger

protected static final Logger _logger

list

protected ArrayList list

factory

protected ObjectFactory factory

waitCount

protected int waitCount

createdCount

protected int createdCount

steadyPoolSize

protected int steadyPoolSize

resizeQuantity

protected int resizeQuantity

maxPoolSize

protected int maxPoolSize

maxWaitTimeInMillis

protected long maxWaitTimeInMillis

idleTimeoutInSeconds

protected int idleTimeoutInSeconds

containerClassLoader

protected ClassLoader containerClassLoader

destroyedCount

protected int destroyedCount

poolSuccess

protected int poolSuccess

poolName

protected String poolName

poolReturned

protected int poolReturned

configData

protected String configData

poolProbeNotifier

protected EjbPoolProbeProvider poolProbeNotifier

appName

protected String appName

modName

protected String modName

ejbName

protected String ejbName

beanId

protected long beanId

Constructor Detail

AbstractPool

protected AbstractPool()

AbstractPool

protected AbstractPool(ObjectFactory factory,
                       long beanId,
                       int steadyPoolSize,
                       int resizeQuantity,
                       int maxPoolsize,
                       long maxWaitTimeInMillis,
                       int idleTimeoutInSeconds,
                       ClassLoader loader)

Method Detail

initializePool

protected void initializePool(ObjectFactory factory,
                              long beanId,
                              int steadyPoolSize,
                              int resizeQuantity,
                              int maxPoolsize,
                              long maxWaitTimeInMillis,
                              int idleTimeoutInSeconds,
                              ClassLoader loader)

setContainerClassLoader

public void setContainerClassLoader(ClassLoader loader)

setInfo

public void setInfo(String appName,
                    String modName,
                    String ejbName)

getObject

public Object getObject(boolean canWait,
                        Object param)
                 throws PoolException

Get an object. Application can use pool.getObject() to get an object instead of using new XXX().

Specified by:

getObject in interface Pool

Parameters:

canWait - Must be true if the calling thread is willing to wait for infinite time to get an object, false if the calling thread does not want to wait at all.

Throws:

PoolException

getObject

public Object getObject(long maxWaitTime,
                        Object param)
                 throws PoolException

Specified by:

getObject in interface Pool

Throws:

PoolException

getObject

public Object getObject(Object param)
                 throws PoolException

Description copied from interface: Pool

Get an object from the pool within the specified time.

Specified by:

getObject in interface Pool

Returns:

an Object or null if an object could not be returned in 'waitForMillis' millisecond.

Throws:

PoolException

returnObject

public void returnObject(Object object)

Return an object back to the pool. An object that is obtained through getObject() must always be returned back to the pool using either returnObject(obj) or through destroyObject(obj).

Specified by:

returnObject in interface Pool

destroyObject

public void destroyObject(Object object)

Destroys an Object. Note that applications should not ignore the reference to the object that they got from getObject(). An object that is obtained through getObject() must always be returned back to the pool using either returnObject(obj) or through destroyObject(obj). This method tells that the object should be destroyed and cannot be reused.

Specified by:

destroyObject in interface Pool

preload

protected void preload(int count)

Preload the pool with objects.

Parameters:

count - the number of objects to be added.

close

public void close()

Close the pool

remove

protected void remove(int count)

removeIdleObjects

protected abstract void removeIdleObjects()

getCreatedCount

public int getCreatedCount()

getDestroyedCount

public int getDestroyedCount()

getPoolSuccess

public int getPoolSuccess()

getSize

public int getSize()

getWaitCount

public int getWaitCount()

getSteadyPoolSize

public int getSteadyPoolSize()

Specified by:

getSteadyPoolSize in interface EJBPoolStatsProvider

getResizeQuantity

public int getResizeQuantity()

getMaxPoolSize

public int getMaxPoolSize()

Specified by:

getMaxPoolSize in interface EJBPoolStatsProvider

getMaxWaitTimeInMillis

public long getMaxWaitTimeInMillis()

getIdleTimeoutInSeconds

public int getIdleTimeoutInSeconds()

setConfigData

public void setConfigData(String configData)

appendStats

public void appendStats(StringBuffer sbuf)

Specified by:

appendStats in interface StatsProvider

getJmsMaxMessagesLoad

public int getJmsMaxMessagesLoad()

Specified by:

getJmsMaxMessagesLoad in interface EJBPoolStatsProvider

getNumBeansInPool

public int getNumBeansInPool()

Specified by:

getNumBeansInPool in interface EJBPoolStatsProvider

getNumThreadsWaiting

public int getNumThreadsWaiting()

Specified by:

getNumThreadsWaiting in interface EJBPoolStatsProvider

getTotalBeansCreated

public int getTotalBeansCreated()

Specified by:

getTotalBeansCreated in interface EJBPoolStatsProvider

getTotalBeansDestroyed

public int getTotalBeansDestroyed()

Specified by:

getTotalBeansDestroyed in interface EJBPoolStatsProvider

getAllMonitoredAttrbuteValues

public String getAllMonitoredAttrbuteValues()

getAllAttrValues

public String getAllAttrValues()

unregisterProbeProvider

protected void unregisterProbeProvider()