desmoj.core.simulator

Class ResourceDB

java.lang.Object

desmoj.core.simulator.ResourceDB

public class ResourceDB
extends java.lang.Object

In the resource database every Simprocess and the resources it requests or holds at the moment are stored. This information is needed i.e. for detecting deadlocks. An instance will be created, when an experiment is created.

Version:

DESMO-J, Ver. 2.5.1c copyright (c) 2015

Author:

Soenke Claassen Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Method Summary

Modifier and Type	Method and Description
boolean	checkForDeadlock(SimProcess unsatProc) This method is called when a SimProcess can not get the resources desired to check if a possible deadlock situation has occured.
boolean	debugIsOn() Shows if this resourceDB currently produces debug output.
void	debugOff() Switches off debug output for this resourceDB.
void	debugOn() Switches on debug output for this resourceDB.
void	deleteResAllocation(Res resPool, SimProcess doneProc, int quantity) Deletes an entry in the resource data base (should be called when a Sim-process is done with it's requested number of resources from a resource pool (Res )).
void	deleteResRequest(SimProcess gainProc, Res resPool, int quantity) Deletes an entry in the resource data base (should be called when a Sim-process receives it's requested number of resources from a resource pool (Res )).
void	noteResourceAllocation(Res resourcePool, SimProcess allocatingProcess, int quantity) Makes an entry in the resource data base when a SimProcess is allocating a number of resources from a resource pool (Res).
void	noteResourceRequest(SimProcess requestingProcess, Res resourcePool, int quantity) Makes an entry in the resource data base when a SimProcess is requesting a number of resources from a resource pool (Res).
java.lang.String	toHtmlString() Returns a string representation of the resource database with some HTML formatting tags.

Methods inherited from class java.lang.Object

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

Method Detail

checkForDeadlock

public boolean checkForDeadlock(SimProcess unsatProc)

This method is called when a SimProcess can not get the resources desired to check if a possible deadlock situation has occured.

Parameters:

unsatProc - desmoj.SimProcess : The SimProcess which can not get the resources desired. The unsatisfied process.

Returns:

boolean : is true if a deadlock is found, false otherwise.

debugIsOn

public boolean debugIsOn()

Shows if this resourceDB currently produces debug output.

Returns:

boolean : true, if resourceDB shows in debug, false if not

debugOff

public void debugOff()

Switches off debug output for this resourceDB.

debugOn

public void debugOn()

Switches on debug output for this resourceDB.

deleteResAllocation

public void deleteResAllocation(Res resPool,
                                SimProcess doneProc,
                                int quantity)

Deletes an entry in the resource data base (should be called when a Sim-process is done with it's requested number of resources from a resource pool (Res )). The SimProcess and the number of requested resources will be deleted in the corresponding Vector (of the Res pool) in the assignment hashtable. The Res pool is the key to this hashtable, specifying the Vector which holds all the (SimProcess/number of requested resources)-pairs.

Parameters:

resPool - desmoj.Res : The resource pool which has provided the resources. (The key to the hashtable)

doneProc - desmoj.SimProcess : The Simprocess giving back his allocated resources. He should be done with the resources now.

quantity - int : The number of resources the SimProcess has used.

deleteResRequest

public void deleteResRequest(SimProcess gainProc,
                             Res resPool,
                             int quantity)

Deletes an entry in the resource data base (should be called when a Sim-process receives it's requested number of resources from a resource pool (Res )). The resource pool and the number of requested resources will be deleted in the request hashtable. The Sim-process is the key to this hashtable, specifying the RequestedResources object which holds the (resource pool/number of requested resources)-pair.

Parameters:

gainProc - desmoj.SimProcess : The Simprocess giving up his request for the resources. Hopefully he gets satisfied.

resPool - desmoj.Res : The resource pool which provides the resources.

quantity - int : The number of resources the SimProcess gets.

noteResourceAllocation

public void noteResourceAllocation(Res resourcePool,
                                   SimProcess allocatingProcess,
                                   int quantity)

Makes an entry in the resource data base when a SimProcess is allocating a number of resources from a resource pool (Res). The Sim-process and the number of allocated resources will be saved in the assignment hashtable. The resource pool is the key to this hashtable.

Parameters:

resourcePool - desmoj.Res : The resource pool which is providing the resources.

allocatingProcess - desmoj.SimProcess : The Simprocess which is allocating the resources.

quantity - int : The number of resources the SimProcess is allocating.

noteResourceRequest

public void noteResourceRequest(SimProcess requestingProcess,
                                Res resourcePool,
                                int quantity)

Makes an entry in the resource data base when a SimProcess is requesting a number of resources from a resource pool (Res). The resource pool and the number of requested resources will be saved in the request hashtable. The SimProcess is the key to this hashtable.

Parameters:

requestingProcess - desmoj.SimProcess : The Simprocess which is requesting the resources.

resourcePool - desmoj.Res : The resource pool which should provide the resources.

quantity - int : The number of resources the SimProcess wants to get.

toHtmlString

public java.lang.String toHtmlString()

Returns a string representation of the resource database with some HTML formatting tags. Lists first for every SimProcess all the resources he is requesting and second for every resource pool (Res) all the SimProcesses that are using resources from that resource pool. This information is useful for debugging purposes.

Returns:

java.lang.String : The string representation of this resource database.