| Copyright | Copyright (c) 2009-2017 David Sorokin <david.sorokin@gmail.com> |
|---|---|
| License | BSD3 |
| Maintainer | David Sorokin <david.sorokin@gmail.com> |
| Stability | experimental |
| Safe Haskell | None |
| Language | Haskell2010 |
Simulation.Aivika.Resource.Preemption.Base
Contents
Description
Tested with: GHC 8.0.1
This module defines the preemptible resource.
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.
Synopsis
- data Resource
- newResource :: Int -> Simulation Resource
- newResourceWithMaxCount :: Int -> Maybe Int -> Simulation Resource
- resourceMaxCount :: Resource -> Maybe Int
- resourceCount :: Resource -> Event Int
- requestResourceWithPriority :: Resource -> Double -> Process ()
- releaseResource :: Resource -> Process ()
- usingResourceWithPriority :: Resource -> Double -> Process a -> Process a
- incResourceCount :: Resource -> Int -> Event ()
- decResourceCount :: Resource -> Int -> Event ()
- alterResourceCount :: Resource -> Int -> Event ()
Resource Type
Represents a preemptible resource.
Creating Resource
Arguments
| :: Int | the initial count (and maximal count too) of the resource |
| -> Simulation Resource |
Create a new resource with the specified initial count that becomes the upper bound as well.
newResourceWithMaxCount Source #
Arguments
| :: Int | the initial count of the resource |
| -> Maybe Int | the maximum count of the resource, which can be indefinite |
| -> Simulation Resource |
Create a new resource with the specified initial and maximum counts,
where Nothing means that the resource has no upper bound.
Resource Properties
resourceMaxCount :: Resource -> Maybe Int Source #
Return the maximum count of the resource, where Nothing
means that the resource has no upper bound.
Requesting for and Releasing Resource
requestResourceWithPriority Source #
Arguments
| :: Resource | the requested resource |
| -> Double | the priority (the less value has a higher 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.
It may preempt another process if the latter aquired the resource before but had a lower priority. Then the current process takes an ownership of the resource.
Release the resource increasing its count and resuming one of the previously suspended or preempted processes as possible.
usingResourceWithPriority Source #
Arguments
| :: Resource | the resource we are going to request for and then release in the end |
| -> Double | the priority (the less value has a higher 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
Increase the count of available resource by the specified number, invoking the awaiting and preempted processes according to their priorities as needed.
Decrease the count of available resource by the specified number, preempting the processes according to their priorities as needed.
Alter the resource count either increasing or decreasing it by calling
incResourceCount or decResourceCount respectively.