com.att.inno.env.util

Class Pool<T>

java.lang.Object

com.att.inno.env.util.Pool<T>

Type Parameters:

T -

public class Pool<T>
extends Object

This Class pools on an As-Needed-Basis any particular kind of class, which is quite suitable for expensive operations. The user calls "get" on a Pool, and if a waiting resource (T) is available, it will be returned. Otherwise, one will be created with the "Creator" class (must be defined for (T)). You can Prime the instances to avoid huge startup costs The returned "Pooled" object simply has to call "done()" and the object is returned to the pool. If the developer does not return the object, a memory leak does not occur. There are no references to the object once "get" is called. However, the developer who does not return the object when done obviates the point of the pool, as new Objects are created in place of the Object not returned when another call to "get" is made. There is a cushion of extra objects, currently defaulted to MAX_RANGE. If the items returned become higher than the MAX_RANGE, the object is allowed to go out of scope, and be cleaned up. the default can be changed on a per-pool basis.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Pool.Creator<T> The Creator Interface give the Pool the ability to Create, Destroy and Validate the Objects it is maintaining.
static class	Pool.Pooled<T> The "Pooled" class is the transient class that wraps the actual Object T for API use/ It gives the ability to return ("done()", or "toss()") the Object to the Pool when processing is finished.

Constructor Summary

Constructors

Constructor and Description
Pool(Pool.Creator<T> creator) Create a new Pool, given the implementation of Creator, which must be able to create/destroy T objects at will.

Method Summary

Modifier and Type	Method and Description
void	drain() Destroy and remove all remaining objects.
Pool.Pooled<T>	get() This is the essential function for Pool.
Pool.Pooled<T>	get(LogTarget lt) This is the essential function for Pool.
int	getMaxRange() Get the maximum number of spare objects allowed at any moment
void	prime(LogTarget lt, int prime) Preallocate a certain number of T Objects.
void	setMaxRange(int max_range) Set a Max Range for numbers of spare objects waiting to be used.
boolean	validate() This function will validate whether the Objects are still in a usable state.

Methods inherited from class java.lang.Object

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

Constructor Detail

Pool

public Pool(Pool.Creator<T> creator)

Create a new Pool, given the implementation of Creator, which must be able to create/destroy T objects at will.

Parameters:

creator -

Method Detail

prime

public void prime(LogTarget lt,
                  int prime)
           throws APIException

Preallocate a certain number of T Objects. Useful for services so that the first transactions don't get hit with all the Object creation costs

Parameters:

lt -

prime -

Throws:

APIException

drain

public void drain()

Destroy and remove all remaining objects. This is valuable for closing down all Allocated objects cleanly for exiting. It is also a good method for removing objects when, for instance, all Objects are invalid because of broken connections, etc.

get

public Pool.Pooled<T> get()
                   throws APIException

This is the essential function for Pool. Get an Object "T" inside a "Pooled" object. If there is a spare Object, then use it. If not, then create and pass back. This one uses a Null LogTarget IMPORTANT: When the use of this object is done (and the object is still in a valid state), then "done()" should be called immediately to allow the object to be reused. That is the point of the Pool... If the Object is in an invalid state, then "toss()" should be used so the Pool doesn't pass on invalid objects to others.

Parameters:

lt -

Returns:

Throws:

APIException

get

public Pool.Pooled<T> get(LogTarget lt)
                   throws APIException

This is the essential function for Pool. Get an Object "T" inside a "Pooled" object. If there is a spare Object, then use it. If not, then create and pass back. If you don't have access to a LogTarget from Env, use LogTarget.NULL IMPORTANT: When the use of this object is done (and the object is still in a valid state), then "done()" should be called immediately to allow the object to be reused. That is the point of the Pool... If the Object is in an invalid state, then "toss()" should be used so the Pool doesn't pass on invalid objects to others.

Parameters:

lt -

Returns:

Throws:

APIException

validate

public boolean validate()

This function will validate whether the Objects are still in a usable state. If not, they are tossed from the Pool. This is valuable to have when Remote Connections go down, and there is a question on whether the Pooled Objects are still functional.

Returns:

getMaxRange

public int getMaxRange()

Get the maximum number of spare objects allowed at any moment

Returns:

setMaxRange

public void setMaxRange(int max_range)

Set a Max Range for numbers of spare objects waiting to be used. No negative numbers are allowed