Simulation.Aivika.Resource.Base

Tested with: GHC 8.0.1

This module defines an optimised version of the resource which can be acquired and then released by the discontinuous process Process. The resource can be either limited by the upper bound (run-time check), or it can have no upper bound. The latter is useful for modeling the infinite queue, for example.

The module is optimised in the sense that this kind of the resource has neither additional signals, nor counters that would may slow down the simulation.

Resource Types

type FCFSResource = Resource FCFS

The ordinary FCFS (First Come - First Serviced) resource.

type LCFSResource = Resource LCFS

The ordinary LCFS (Last Come - First Serviced) resource.

type SIROResource = Resource SIRO

The SIRO (Serviced in Random Order) resource.

type PriorityResource = Resource StaticPriorities

The resource with static priorities.

data Resource s

Represents the resource with strategy s applied for queuing the requests.

Instances

Eq (Resource s)

Methods

(==) :: Resource s -> Resource s -> Bool

(/=) :: Resource s -> Resource s -> Bool

Creating Resource

newFCFSResource

Arguments

:: Int

the initial count (and maximal count too) of the resource

-> Simulation FCFSResource

Create a new FCFS resource with the specified initial count which value becomes the upper bound as well.

newFCFSResourceWithMaxCount

Arguments

:: Int

the initial count of the resource

-> Maybe Int

the maximum count of the resource, which can be indefinite

-> Simulation FCFSResource

Create a new FCFS resource with the specified initial and maximum counts, where Nothing means that the resource has no upper bound.

newLCFSResource

Arguments

:: Int

the initial count (and maximal count too) of the resource

-> Simulation LCFSResource

Create a new LCFS resource with the specified initial count which value becomes the upper bound as well.

newLCFSResourceWithMaxCount

Arguments

:: Int

the initial count of the resource

-> Maybe Int

the maximum count of the resource, which can be indefinite

-> Simulation LCFSResource

Create a new LCFS resource with the specified initial and maximum counts, where Nothing means that the resource has no upper bound.

newSIROResource

Arguments

:: Int

the initial count (and maximal count too) of the resource

-> Simulation SIROResource

Create a new SIRO resource with the specified initial count which value becomes the upper bound as well.

newSIROResourceWithMaxCount

Arguments

:: Int

the initial count of the resource

-> Maybe Int

the maximum count of the resource, which can be indefinite

-> Simulation SIROResource

Create a new SIRO resource with the specified initial and maximum counts, where Nothing means that the resource has no upper bound.

newPriorityResource

Arguments

:: Int

the initial count (and maximal count too) of the resource

-> Simulation PriorityResource

Create a new priority resource with the specified initial count which value becomes the upper bound as well.

newPriorityResourceWithMaxCount

Arguments

:: Int

the initial count of the resource

-> Maybe Int

the maximum count of the resource, which can be indefinite

-> Simulation PriorityResource

Create a new priority resource with the specified initial and maximum counts, where Nothing means that the resource has no upper bound.

newResource

Arguments

:: QueueStrategy s

=> s

the strategy for managing the queuing requests

-> Int

the initial count (and maximal count too) of the resource

-> Simulation (Resource s)

Create a new resource with the specified queue strategy and initial count. The last value becomes the upper bound as well.

newResourceWithMaxCount

Arguments

:: QueueStrategy s

=> s

the strategy for managing the queuing requests

-> Int

the initial count of the resource

-> Maybe Int

the maximum count of the resource, which can be indefinite

-> Simulation (Resource s)

Create a new resource with the specified queue strategy, initial and maximum counts, where Nothing means that the resource has no upper bound.

Resource Properties

resourceStrategy :: Resource s -> s

Return the strategy applied for queuing the requests.

resourceMaxCount :: Resource s -> Maybe Int

Return the maximum count of the resource, where Nothing means that the resource has no upper bound.

resourceCount :: Resource s -> Event Int

Return the current count of the resource.

Requesting for and Releasing Resource

requestResource

Arguments

:: EnqueueStrategy s

=> Resource s

the requested resource

-> Process ()

Request for the resource decreasing its count in case of success, otherwise suspending the discontinuous process until some other process releases the resource.

requestResourceWithPriority

Arguments

:: PriorityQueueStrategy s p

=> Resource s

the requested resource

-> p

the priority

-> Process ()

Request with the priority for the resource decreasing its count in case of success, otherwise suspending the discontinuous process until some other process releases the resource.

tryRequestResourceWithinEvent

Arguments

:: Resource s

the resource which we try to request for

-> Event Bool

Try to request for the resource decreasing its count in case of success and returning True in the Event monad; otherwise, returning False.

releaseResource

Arguments

:: DequeueStrategy s

=> Resource s

the resource to release

-> Process ()

Release the resource increasing its count and resuming one of the previously suspended processes as possible.

releaseResourceWithinEvent

Arguments

:: DequeueStrategy s

=> Resource s

the resource to release

-> Event ()

Release the resource increasing its count and resuming one of the previously suspended processes as possible.

usingResource

Arguments

:: EnqueueStrategy s

=> Resource s

the resource we are going to request for and then release in the end

-> Process a

the action we are going to apply having the resource

-> Process a

the result of the action

Acquire the resource, perform some action and safely release the resource in the end, even if the IOException was raised within the action.

usingResourceWithPriority

Arguments

:: PriorityQueueStrategy s p

=> Resource s

the resource we are going to request for and then release in the end

-> p

the priority

-> Process a

the action we are going to apply having the resource

-> Process a

the result of the action

Acquire the resource with the specified priority, perform some action and safely release the resource in the end, even if the IOException was raised within the action.

Altering Resource

incResourceCount

Arguments

:: DequeueStrategy s

=> Resource s

the resource

-> Int

the increment for the resource count

-> Event ()

Increase the count of available resource by the specified number, invoking the awaiting processes as needed.

decResourceCount

Arguments

:: EnqueueStrategy s

=> Resource s

the resource

-> Int

the decrement for the resource count

-> Process ()

Decrease the count of available resource by the specified number, waiting for the processes capturing the resource as needed.