com.kheops.util

Class KObjectPool<T>

java.lang.Object

com.kheops.util.KObjectPool<T>

All Implemented Interfaces:

KSchedulerClient

Direct Known Subclasses:

DatabaseConnectionPool, JMapNetworkConnectionPool, JMapServerConnectionPool, JMapServerRemoteConnectionPool, JMapServerThreadPool, KSocketConnectionPool, SdeConnectionPool

public abstract class KObjectPool<T>
extends java.lang.Object
implements KSchedulerClient

This abstract class encapsulates a pool of objects. Subclasses will override the method to manage these objects.

The Object pool consists of
-minimumSize : the initial number of objects

-maximumSize : the maximum number of objects

-cleanupPeriod : the amount of time between cleanups. During a clean up all the
objects created after the initial creation (objects over the minimum)
that are inactive for a period longer than the shrink period will be closed.

-shrinkTime : the amount of time extra objects can remain inactive before it is
eligible for clean up

-recyclePeriod : the amount of time an initial object can remain inactive before it is recycled
(objects are closed and reopen)

Field Summary

Fields

Modifier and Type	Field and Description
protected long	cleanupPeriod
protected long	recyclePeriod
protected long	shrinkTime
static long	TIMEOUT_UNDEFINED
static long	TIMEOUT_UNLIMITED

Constructor Summary

Constructors

Constructor and Description
KObjectPool() Creates a new instance

Method Summary

Modifier and Type	Method and Description
protected void	apply(java.util.function.Consumer<T> consumer) Apply a non-blocking operation on each pool workers.
void	checkIn(T o) This method sets the object available
T	checkOut() This method makes a request for an unlocked object from the pool.
T	checkOut(long timeout, java.util.concurrent.TimeUnit unit) This method makes a request for an unlocked object from the pool.
void	close() This method closes one by one all the objects currently opened for this the pool
abstract T	create() Creates the object encapsulating the appropriate object
void	createUnlockedInstance() Creates an unlocked instance of the appropriate object and adds it to the pool.
abstract void	expire(T o) This method closes the object
long	getDefaultTimeout() Gets the default timeout to use on checkout action if no timeout is specified.
protected int	getId()
PoolMonitoringInfo	getMonitoringInfo() This method gets the PoolMonitorInfo associated with the KObject pool instance.
int	getPoolMaximumSize() Gets the maximum number of concurrent objects allowed
int	getPoolSize() Gets the number of objects currently used
int	getPoolUsageCount() Gets the number of currently used objects
int	getPoolUsagePeak() Gets the peak number of objects used simultaneously this method is used for statistic reasons.
protected long	getSystemDefaultTimeout()
void	initialize(int minimumSize) Initializes a KObjectPool instance with the specified minimum size
void	initialize(int minimumSize, long recyclePeriod) Initializes a KObjectPool instance with the specified minimum size and recycle period
void	initialize(int minimumSize, long shrinkTime, long cleanupPeriod, long recyclePeriod) Initializes a KObjectPool instance with the specified minimum size, recycle period, clean up period and shrink period
protected void	internalErrorOccurred(java.lang.Exception e)
void	reset() This will close and reinitialize the pool.
protected void	resourceAdded(T o) No-op hook that allows implementation instructions after resource creation.
void	schCallback(int jobId) This method is automatically called by the KScheduler to either perform the clean up or object recycle jobs
void	setDefaultTimeout(long defaultTimeout) Sets the default timeout to use on checkout action if no timeout is specified.
void	setPoolMaximumSize(int size) Sets the maximum number of objects allowed
void	setPoolMinimumSize(int size) Sets the pool minimum size
abstract boolean	validate(T o) This method checks if the object is valid

Methods inherited from class java.lang.Object

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

Field Detail

TIMEOUT_UNDEFINED

public static final long TIMEOUT_UNDEFINED

See Also:

Constant Field Values

TIMEOUT_UNLIMITED

public static final long TIMEOUT_UNLIMITED

See Also:

Constant Field Values

shrinkTime

protected long shrinkTime

cleanupPeriod

protected long cleanupPeriod

recyclePeriod

protected long recyclePeriod

Constructor Detail

KObjectPool

public KObjectPool()

Creates a new instance

Method Detail

initialize

public void initialize(int minimumSize)
                throws java.lang.Exception

Initializes a KObjectPool instance with the specified minimum size

Parameters:

minimumSize - the minimum number of objects in this pool

Throws:

java.lang.Exception - if an error occurred while initializing the object pool

initialize

public void initialize(int minimumSize,
                       long recyclePeriod)
                throws java.lang.Exception

Initializes a KObjectPool instance with the specified minimum size and recycle period

Parameters:

minimumSize - the minimum number of objects in this pool

recyclePeriod - the amount of time an initial object can remain inactive before it is recycled (closed than reopen).

Throws:

java.lang.Exception - if an error occurred while initializing the object pool

initialize

public void initialize(int minimumSize,
                       long shrinkTime,
                       long cleanupPeriod,
                       long recyclePeriod)
                throws java.lang.Exception

Initializes a KObjectPool instance with the specified minimum size, recycle period, clean up period and shrink period

Parameters:

minimumSize - the minimum number of objects in this pool

shrinkTime - the amount of time extra objects can remain inactive before it eligible for cleanup

cleanupPeriod - the amount of time between cleanups

recyclePeriod - the amount of time an initial object can remain inactive before it is recycled (closed than reopen).

Throws:

java.lang.Exception - if an error occurred while initializing the object pool

create

public abstract T create()
                  throws java.lang.Exception

Creates the object encapsulating the appropriate object

Returns:

the corresponding object

Throws:

java.lang.Exception - if an error occurred while creating the object

validate

public abstract boolean validate(T o)

This method checks if the object is valid

Parameters:

o - object to validate

Returns:

true if the object is valid false otherwise

expire

public abstract void expire(T o)

This method closes the object

Parameters:

o - the object to be expired

getPoolSize

public int getPoolSize()

Gets the number of objects currently used

Returns:

the number of objects currently used

getPoolMaximumSize

public int getPoolMaximumSize()

Gets the maximum number of concurrent objects allowed

Returns:

maximumSize the maximum number of allowed objects

getId

protected int getId()

internalErrorOccurred

protected void internalErrorOccurred(java.lang.Exception e)

setPoolMaximumSize

public void setPoolMaximumSize(int size)

Sets the maximum number of objects allowed

Parameters:

size - the corresponding integer number

setPoolMinimumSize

public void setPoolMinimumSize(int size)

Sets the pool minimum size

Parameters:

size - the corresponding integer value

getPoolUsageCount

public int getPoolUsageCount()

Gets the number of currently used objects

Returns:

the corresponding integer value

getPoolUsagePeak

public int getPoolUsagePeak()

Gets the peak number of objects used simultaneously this method is used for statistic reasons.

Returns:

the corresponding integer value

getDefaultTimeout

public long getDefaultTimeout()

Gets the default timeout to use on checkout action if no timeout is specified. This value either comes from the server configuration or can be configured directly for this instance.

Returns:

timeout value in milliseconds

Since:

7.0

setDefaultTimeout

public void setDefaultTimeout(long defaultTimeout)

Sets the default timeout to use on checkout action if no timeout is specified.

Parameters:

defaultTimeout - value in milliseconds

Since:

7.0

getSystemDefaultTimeout

protected long getSystemDefaultTimeout()

createUnlockedInstance

public void createUnlockedInstance()
                            throws java.lang.Exception

Creates an unlocked instance of the appropriate object and adds it to the pool.

Throws:

java.lang.Exception - if an error occurred while creating the object

java.util.concurrent.TimeoutException - if the operation is not executed within the default timeout delay.

checkOut

public T checkOut()
           throws java.lang.Exception

This method makes a request for an unlocked object from the pool. Afterward the returned object becomes locked and cannot be used by another source unless it is checkIn.

Returns:

an unlocked free object

Throws:

java.lang.Exception - if an error occurred while checking out an object

java.util.concurrent.TimeoutException - if the operation is not executed within the default timeout delay.

checkOut

public T checkOut(long timeout,
                  java.util.concurrent.TimeUnit unit)
           throws java.lang.Exception

This method makes a request for an unlocked object from the pool. Afterward the returned object becomes locked and cannot be used by another source unless it is checkIn. Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available. Timeout value must be greater than 0 to be supported.

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

an unlocked free object

Throws:

java.lang.Exception - if an error occurred while checking out an object

java.util.concurrent.TimeoutException - if the operation is not executed within the specified timeout delay.

Since:

7.0

checkIn

public void checkIn(T o)

This method sets the object available

Parameters:

o - the corresponding object

close

public void close()

This method closes one by one all the objects currently opened for this the pool

reset

public void reset()
           throws java.lang.Exception

This will close and reinitialize the pool.

Throws:

java.lang.Exception

schCallback

public void schCallback(int jobId)

This method is automatically called by the KScheduler to either perform the clean up or object recycle jobs

Specified by:

schCallback in interface KSchedulerClient

Parameters:

jobId - the job Id to determine which job will be done

getMonitoringInfo

public PoolMonitoringInfo getMonitoringInfo()

This method gets the PoolMonitorInfo associated with the KObject pool instance. The PoolMonitorInfo maintains the pool statistics

Returns:

the corresponding PoolMonitorInfo instance

See Also:

PoolMonitoringInfo

resourceAdded

protected void resourceAdded(T o)

No-op hook that allows implementation instructions after resource creation.

Parameters:

o - the corresponding object

apply

protected void apply(java.util.function.Consumer<T> consumer)

Apply a non-blocking operation on each pool workers.