StateMachine¶
The MARTe StateMachine components allows to associate the sending of Messages to events.
Each state contains one, or more, StateMachineEvent elements. The StateMachine can be in one (and only one) state at a given time.
The StateMachine is a key component which is used in many MARTe applications to synchronise the application state against the external environment.
Upon receiving of a Message, the StateMachine will verify if the Message function (see GetFunction) is equal to the name of any of the declared StateMachineEvent elements for the current StateMachine state. If it is, the StateMachine will change to the declared state and trigger any messages associated to this transition.
Note
If a state change requests arrives while the state is being changed, this request will be queued and served once the previous state transition is completed.
Configuration¶
Each state is declared as a ReferenceContainer of StateMachineEvent elements.
+StateMachine = {
Class = StateMachine
+STATE1 = {
Class = ReferenceContainer
+GOTOSTATE2 = {
Class = StateMachineEvent
...
}
+ERROR = {
Class = StateMachineEvent
...
}
...
}
+STATE2 = {
Class = ReferenceContainer
+GOTOSTATE1 = {
Class = StateMachineEvent
...
}
+ERROR = {
Class = StateMachineEvent
...
}
...
}
Each StateMachineEvent contains the NextState (where to go), the NextStateError (where to go in case of any error while sending the messages) and one or more messages to be sent when the event is triggered.
+StateMachine = {
Class = StateMachine
+STATE1 = {
Class = ReferenceContainer
+GOTOSTATE2 = {
Class = StateMachineEvent
NextState = "STATE2"
NextStateError = "ERROR"
Timeout = 0
+DoSomething = {
Class = Message
Destination = Receiver1
Mode = ExpectsReply
Function = Function1
+Parameters = {
Class = ConfigurationDatabase
param1 = 2
param2 = 3.14
}
}
+DoSomethingElse = {
Class = Message
Destination = Receiver1
Mode = ExpectsReply
Function = Function0
}
}
+GOTOSTATE3 = {
Class = StateMachineEvent
NextState = "STATE3"
NextStateError = "ERROR"
Timeout = 0
+DoSomething = {
Class = Message
Destination = Receiver1
Mode = ExpectsReply
Function = Function1
+Parameters = {
Class = ConfigurationDatabase
param1 = 4
param2 = 5.312
}
}
}
...
Note
The StateMachine is not compatible with the usage of the GAMBareScheduler for more than two states. The first state being the state started in and then the second being the next state. This is because the StartNextExecution function of the GAMBareScheduler is a non-returning infinite while loop and stalls the StateMachine at the state transition point while executing the second state.
The Timeout parameter sets the maximum amount of time allowed for the state transition (including waiting for all the requested replies to arrive). An infinite timeout is defined with a value of 0.
Note
The message replies can be used to guarantee that the state transitions only complete when given events occur/complete.
If an event named ENTER of type ReferenceContainer exists, all of its contained messages will be triggered when entering the state.
+StateMachine = {
Class = StateMachine
+STATE1 = {
Class = ReferenceContainer
+ENTER = {
Class = ReferenceContainer
+DoSomethingWhenEntering = {
Class = Message
Destination = Receiver1
Mode = ExpectsReply
Function = Function1
+Parameters = {
Class = ConfigurationDatabase
param1 = 4
param2 = 5.312
}
}
+DoSomethingElseWhenEntering = {
Class = Message
Destination = Receiver2
Mode = ExpectsReply
Function = Function1
+Parameters = {
Class = ConfigurationDatabase
param1 = 8
param2 = -5.312
}
}
}
+GOTOSTATE2 = {
Class = StateMachineEvent
...
Examples¶
The following is an example which shows how a state machine can be used to trigger remote function calls:
Example of a StateMachine receiving and triggering messages.¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 | /**
* @file StateMachineExample1.cpp
* @brief Source file for class StateMachineExample1
* @date 25/04/2018
* @author Andre Neto
*
* @copyright Copyright 2015 F4E | European Joint Undertaking for ITER and
* the Development of Fusion Energy ('Fusion for Energy').
* Licensed under the EUPL, Version 1.1 or - as soon they will be approved
* by the European Commission - subsequent versions of the EUPL (the "Licence")
* You may not use this work except in compliance with the Licence.
* You may obtain a copy of the Licence at: http://ec.europa.eu/idabc/eupl
*
* @warning Unless required by applicable law or agreed to in writing,
* software distributed under the Licence is distributed on an "AS IS"
* basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the Licence permissions and limitations under the Licence.
* @details This source file contains the definition of all the methods for
* the class StateMachineExample1 (public, protected, and private). Be aware that some
* methods, such as those inline could be defined on the header file, instead.
*/
#define DLL_API
/*---------------------------------------------------------------------------*/
/* Standard header includes */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
/* Project header includes */
/*---------------------------------------------------------------------------*/
#include "AdvancedErrorManagement.h"
#include "CLASSMETHODREGISTER.h"
#include "ConfigurationDatabase.h"
#include "ErrorLoggerExample.h"
#include "ObjectRegistryDatabase.h"
#include "RegisteredMethodsMessageFilter.h"
#include "StandardParser.h"
#include "StateMachine.h"
/*---------------------------------------------------------------------------*/
/* Static definitions */
/*---------------------------------------------------------------------------*/
namespace MARTe2Tutorial {
/**
* @brief A MARTe::Object class that registers a set of RPC functions that can be called
* with messages.
*/
class MessageReceiverEx1: public MARTe::Object, public MARTe::MessageI {
public:
CLASS_REGISTER_DECLARATION()
/**
* @brief Install the RegisteredMethodsMessageFilter filter.
*/
MessageReceiverEx1 () : MARTe::Object(), MARTe::MessageI() {
using namespace MARTe;
filter = ReferenceT<RegisteredMethodsMessageFilter>(GlobalObjectsDatabase::Instance()->GetStandardHeap());
filter->SetDestination(this);
MessageI::InstallMessageFilter(filter);
fun0Called = false;
fun1Called = false;
fun2Called = false;
fun3Called = false;
}
virtual ~MessageReceiverEx1 () {
if (GetName() != NULL) {
REPORT_ERROR_STATIC(MARTe::ErrorManagement::Information, "No more references pointing at %s [%s]. "
"The Object will be safely deleted.", GetName(), GetClassProperties()->GetName());
}
}
virtual void Purge(MARTe::ReferenceContainer &purgeList) {
RemoveMessageFilter(filter);
}
MARTe::ErrorManagement::ErrorType Function0 () {
REPORT_ERROR_STATIC(MARTe::ErrorManagement::Information, "Function0 called.");
fun0Called = true;
return MARTe::ErrorManagement::NoError;
}
MARTe::ErrorManagement::ErrorType Function1 (MARTe::uint32 a, MARTe::float32 b) {
REPORT_ERROR_STATIC(MARTe::ErrorManagement::Information, "Received %u %f.", a, b);
fun1Called = true;
return MARTe::ErrorManagement::NoError;
}
MARTe::ErrorManagement::ErrorType Function2 (MARTe::int32 a, MARTe::float32 b, MARTe::uint32 c) {
REPORT_ERROR_STATIC(MARTe::ErrorManagement::Information, "Received %u %f %u.", a, b,c);
fun2Called = true;
return MARTe::ErrorManagement::NoError;
}
MARTe::ErrorManagement::ErrorType Function3 (MARTe::StreamString a) {
REPORT_ERROR_STATIC(MARTe::ErrorManagement::Information, "Received %s.", a.Buffer());
fun3Called = true;
return MARTe::ErrorManagement::NoError;
}
bool fun0Called;
bool fun1Called;
bool fun2Called;
bool fun3Called;
private:
MARTe::ReferenceT<MARTe::RegisteredMethodsMessageFilter> filter;
};
CLASS_REGISTER(MessageReceiverEx1, "")
CLASS_METHOD_REGISTER(MessageReceiverEx1, Function0)
CLASS_METHOD_REGISTER(MessageReceiverEx1, Function1)
CLASS_METHOD_REGISTER(MessageReceiverEx1, Function2)
CLASS_METHOD_REGISTER(MessageReceiverEx1, Function3)
}
/*---------------------------------------------------------------------------*/
/* Method definitions */
/*---------------------------------------------------------------------------*/
int main(int argc, char **argv) {
using namespace MARTe;
using namespace MARTe2Tutorial;
SetErrorProcessFunction(&ErrorProcessExampleFunction);
StreamString configurationCfg = ""
"+Receiver1 = {\n"
" Class = MessageReceiverEx1\n"
"}\n"
"+Receiver2 = {\n"
" Class = MessageReceiverEx1\n"
"}\n"
"+StateMachineExample1 = {\n"
" Class = StateMachine\n"
" +STATE1 = {\n"
" Class = ReferenceContainer\n"
" +GOTOSTATE2 = {\n"
" Class = StateMachineEvent\n"
" NextState = \"STATE2\"\n"
" NextStateError = \"STATE1\"\n"
" Timeout = 0\n"
" +DoSomethingOnRec1 = {\n"
" Class = Message\n"
" Destination = Receiver1\n"
" Mode = ExpectsReply\n"
" Function = Function1\n"
" +Parameters = {\n"
" Class = ConfigurationDatabase\n"
" param1 = 2\n"
" param2 = 3.14\n"
" }\n"
" }\n"
" +DoSomethingElseOnRec1 = {\n"
" Class = Message\n"
" Destination = Receiver1\n"
" Mode = ExpectsReply\n"
" Function = Function0\n"
" }\n"
" }\n"
" +GOTOSTATE3 = {\n"
" Class = StateMachineEvent\n"
" NextState = \"STATE3\"\n"
" NextStateError = \"STATE1\"\n"
" Timeout = 0\n"
" +DoSomethingOnRec2 = {\n"
" Class = Message\n"
" Destination = \"Receiver1\"\n"
" Mode = ExpectsReply\n"
" Function = Function1\n"
" +Parameters = {\n"
" Class = ConfigurationDatabase\n"
" param1 = 2\n"
" param2 = 3.14\n"
" }\n"
" }\n"
" +DoSomethingElseOnRec2 = {\n"
" Class = Message\n"
" Destination = \"Receiver2\"\n"
" Mode = ExpectsReply\n"
" Function = Function0\n"
" }\n"
" }\n"
" }\n"
" +STATE2 = {\n"
" Class = ReferenceContainer\n"
" +GOTOSTATE1 = {\n"
" Class = StateMachineEvent\n"
" NextState = \"STATE1\"\n"
" NextStateError = \"STATE1\"\n"
" Timeout = 0\n"
" +DoSomethingOnRec1 = {\n"
" Class = Message\n"
" Destination = Receiver1\n"
" Mode = ExpectsReply\n"
" Function = Function3\n"
" +Parameters = {\n"
" Class = ConfigurationDatabase\n"
" param1 = \"BACKTOSTATE1!\"\n"
" }\n"
" }\n"
" }\n"
" }\n"
" +STATE3 = {\n"
" Class = ReferenceContainer\n"
" +ENTER = {\n"
" Class = ReferenceContainer\n"
" +DoSomethingOnRec1 = {\n"
" Class = Message\n"
" Destination = Receiver1\n"
" Mode = ExpectsReply\n"
" Function = Function2\n"
" +Parameters = {\n"
" Class = ConfigurationDatabase\n"
" param1 = 1"
" param2 = 2"
" param3 = 3"
" }\n"
" }\n"
" }"
" +GOTOSTATE2 = {\n"
" Class = StateMachineEvent\n"
" NextState = \"STATE2\"\n"
" NextStateError = \"STATE2\"\n"
" Timeout = 0\n"
" +DoSomethingOnRec2 = {\n"
" Class = Message\n"
" Destination = Receiver2\n"
" Mode = ExpectsReply\n"
" Function = Function3\n"
" +Parameters = {\n"
" Class = ConfigurationDatabase\n"
" param1 = \"BACKTOSTATE2!\"\n"
" }\n"
" }\n"
" }\n"
" }\n"
"}\n";
REPORT_ERROR_STATIC(ErrorManagement::Information, "Loading CFG:\n%s", configurationCfg.Buffer());
ConfigurationDatabase cdb;
StreamString err;
//Force the string to be seeked to the beginning.
configurationCfg.Seek(0LLU);
StandardParser parser(configurationCfg, cdb, &err);
bool ok = parser.Parse();
ObjectRegistryDatabase *ord = ObjectRegistryDatabase::Instance();
if (ok) {
//After parsing the tree is pointing at the last leaf
cdb.MoveToRoot();
ok = ord->Initialise(cdb);
}
else {
StreamString errPrint;
errPrint.Printf("Failed to parse %s", err.Buffer());
REPORT_ERROR_STATIC(ErrorManagement::ParametersError, errPrint.Buffer());
}
ReferenceT<MessageReceiverEx1> rec1 = ord->Find("Receiver1");
ReferenceT<MessageReceiverEx1> rec2 = ord->Find("Receiver2");
//Send a message to the state machine
ReferenceT<Message> msg1(GlobalObjectsDatabase::Instance()->GetStandardHeap());
ConfigurationDatabase msg1Cdb;
msg1Cdb.Write("Destination", "StateMachineExample1");
msg1Cdb.Write("Function", "GOTOSTATE3");
msg1->Initialise(msg1Cdb);
MessageI::SendMessage(msg1, NULL);
while (!rec2->fun0Called) {
Sleep::Sec(0.1);
}
ReferenceT<Message> msg2(GlobalObjectsDatabase::Instance()->GetStandardHeap());
ConfigurationDatabase msg2Cdb;
msg2Cdb.Write("Destination", "StateMachineExample1");
msg2Cdb.Write("Function", "GOTOSTATE2");
msg2->Initialise(msg2Cdb);
MessageI::SendMessage(msg2, NULL);
while (!rec2->fun3Called) {
Sleep::Sec(0.1);
}
ReferenceT<Message> msg3(GlobalObjectsDatabase::Instance()->GetStandardHeap());
ConfigurationDatabase msg3Cdb;
msg3Cdb.Write("Destination", "StateMachineExample1");
msg3Cdb.Write("Function", "GOTOSTATE1");
msg3->Initialise(msg3Cdb);
MessageI::SendMessage(msg3, NULL);
while (!rec1->fun3Called) {
Sleep::Sec(0.1);
}
//Purge all the Objects!
ObjectRegistryDatabase::Instance()->Purge();
return 0;
}
|
Instructions on how to compile and execute the examples can be found here.