org.jini.rio.resources.resource
Class ResourcePool

java.lang.Object
  org.jini.rio.resources.resource.ResourcePool

Direct Known Subclasses:

ThreadPool

public abstract class ResourcePool
extends Object

A generic abstract class to handle a finite set of resources

Field Summary

protected LinkedList	alloced The alloced list
protected LinkedList	freed The free list
protected String	identifier Unique identifier for a resourcePool instance
protected int	max The maximum # of resources allowed
protected int	min The minimum # of resources to create at init time
protected int	numCreated The total number of resources currently created

Constructor Summary

ResourcePool()

Method Summary

protected void	allocResource(Object resource) allocates a Resource and performs any initilization required to manage the alloced resource
protected abstract Object	create() Abstract method for creating a specific resource in the sub-class
protected Object	createResource() creates a new Resource and performs any initilization required to manage the resource
protected void	createResources() Pre-creates the minimum number of resources
protected void	createResources(int number) Pre-creates the specified number of resources
protected abstract void	dispose(Object obj) Abstract method for disposing a specific resource in the sub-class
protected void	disposeResource(Object resource) disposes of a Resource and performs any clean-up required to manage the resource
protected void	freeResource(Object resource) frees a Resource and performs any clean-up required to manage the resource
Object	get() Get a Resource from the pool, blocking forever until a resource becomes available
Object	get(long timeout) Get a Resource from the pool, blocking for a specified time until a resource becomes available, a zero timeout blocks forever.
int	getAllocedSize() Gets the number of resources currently assigned
int	getFreedSize() Gets the number of resources currently available for assignment
String	getIdentifier() Gets the unique identifier for this instance
static ResourcePool	getInstance(String key) Gets a registered ResourcePool
int	getMax() Gets the maximum number of resources allowed
int	getMin() Gets the minimum number of resources
int	getSize() Gets the total number of resources created
protected void	register() Registers this resource into the common ResourcePool
protected void	register(String key) Registers this resource into the common ResourcePool
static void	register(String key, ResourcePool pool) Registers a resource into the common ResourcePool
void	release(Object obj) Release a resource back to the pool after its use is completed.
void	remove(Object obj) Remove a resource all together from the pool and dispose of it
void	setIdentifier(String identifier) Sets the unique identifier for this instance
void	setMax(int max) Sets the maximum number of resources
void	setMin(int min) Sets the minimum number of resources, this method has no effect on the number of created resources, if the new minimum is less than the old minimum.
String	toString() Returns a string representation of the ResourcePool
protected abstract boolean	validate(Object obj) Abstract method for validating a resource

Methods inherited from class java.lang.Object

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

Field Detail

freed

protected LinkedList freed

The free list

alloced

protected LinkedList alloced

The alloced list

min

protected int min

The minimum # of resources to create at init time

max

protected int max

The maximum # of resources allowed

numCreated

protected int numCreated

The total number of resources currently created

identifier

protected String identifier

Unique identifier for a resourcePool instance

Constructor Detail

ResourcePool

public ResourcePool()

Method Detail

create

protected abstract Object create()
                          throws ResourceUnavailableException

Abstract method for creating a specific resource in the sub-class

Returns:

the resource

Throws:

ResourceUnavailableException - if an error occured in creating the resource

dispose

protected abstract void dispose(Object obj)

Abstract method for disposing a specific resource in the sub-class

Parameters:

obj - the resource to dispose

validate

protected abstract boolean validate(Object obj)

Abstract method for validating a resource

Parameters:

obj - the resource to validate

Returns:

true if resource is still valid

release

public void release(Object obj)

Release a resource back to the pool after its use is completed.

Parameters:

obj - the resource object

remove

public void remove(Object obj)

Remove a resource all together from the pool and dispose of it

Parameters:

obj - the resource object

get

public Object get()
           throws ResourceUnavailableException

Get a Resource from the pool, blocking forever until a resource becomes available

Returns:

the resource object

Throws:

ResourceUnavailableException - if an error occured in creating the resource

get

public Object get(long timeout)
           throws ResourceUnavailableException

Get a Resource from the pool, blocking for a specified time until a resource becomes available, a zero timeout blocks forever.

Parameters:

timeout - the time in milliseconds to wait for a resource to become available

Returns:

the resource object

Throws:

ResourceUnavailableException - if an error occured in creating the resource

ResourceUnavailableException - if no resource becomes available before the timeout period expires

createResource

protected Object createResource()
                         throws ResourceUnavailableException

creates a new Resource and performs any initilization required to manage the resource

Returns:

the new resource

Throws:

ResourceUnavailableException

allocResource

protected void allocResource(Object resource)

allocates a Resource and performs any initilization required to manage the alloced resource

Parameters:

resource - the resource to allocate

freeResource

protected void freeResource(Object resource)

frees a Resource and performs any clean-up required to manage the resource

Parameters:

resource - the resource to free

disposeResource

protected void disposeResource(Object resource)

disposes of a Resource and performs any clean-up required to manage the resource

Parameters:

resource - the resource to dispose

getFreedSize

public int getFreedSize()

Gets the number of resources currently available for assignment

Returns:

the number of resources currently available for assignment

getAllocedSize

public int getAllocedSize()

Gets the number of resources currently assigned

Returns:

the number of resources currently assigned

getSize

public int getSize()

Gets the total number of resources created

Returns:

the total number of resources created

getMin

public int getMin()

Gets the minimum number of resources

Returns:

the minimum number of resources

getMax

public int getMax()

Gets the maximum number of resources allowed

Returns:

the maximum number of resources allowed

setMin

public void setMin(int min)

Sets the minimum number of resources, this method has no effect on the number of created resources, if the new minimum is less than the old minimum.

Parameters:

min - the minimum number of resources

Throws:

IllegalArgumentException - if minimum is less than zero or the minimum is is greater than the maximum

setIdentifier

public void setIdentifier(String identifier)

Sets the unique identifier for this instance

Parameters:

identifier - the unique identifier for this instance

getIdentifier

public String getIdentifier()

Gets the unique identifier for this instance

Returns:

the unique identifier for this instance

createResources

protected void createResources()
                        throws ResourceUnavailableException

Pre-creates the minimum number of resources

Throws:

ResourceUnavailableException

createResources

protected void createResources(int number)
                        throws ResourceUnavailableException

Pre-creates the specified number of resources

Parameters:

number - the number of resources to create

Throws:

ResourceUnavailableException

setMax

public void setMax(int max)

Sets the maximum number of resources

Parameters:

max - the maximum number of resources

Throws:

IllegalArgumentException - if maximum is less than the minimum

getInstance

public static ResourcePool getInstance(String key)

Gets a registered ResourcePool

Parameters:

key - the identifier for the type of resource pool

Returns:

the resource pool or null, if one is not registered for the key.

register

protected void register()

Registers this resource into the common ResourcePool

register

protected void register(String key)

Registers this resource into the common ResourcePool

Parameters:

key - the identifier for the type of resource pool

register

public static void register(String key,
                            ResourcePool pool)

Registers a resource into the common ResourcePool

Parameters:

key - the identifier for the type of resource pool

pool - the ResourcePool being registered

toString

public String toString()

Returns a string representation of the ResourcePool

Overrides:

toString in class Object

Returns:

a string representation of the ResourcePool