Simple State Machine written in Objective-C

Very simple state machine written in Objective-C.

Features:

• Entry actions
• Exit actions
• Actions on transitions
• Decisions
• Asynchronous mode
• Timing events in asynchronous mode
• Logging

Turnstile example

//Create structure  
SMStateMachine *sm = [[SMStateMachine alloc] init];  
sm.globalExecuteIn = self; //execute all selectors on self object  
SMState *opened = [sm createState:@"open"];  
SMState *closed = [sm createState:@"closed"];  
sm.initialState = closed;  
[opened setEntrySelector:@selector(greenLightOn)];  
[closed setEntrySelector:@selector(redLightOn)];  
[sm transitionFrom:closed to:opened forEvent:@"coin"];  
[sm transitionFrom:opened to:closed forEvent:@"pass"];  
[sm transitionFrom:opened to:closed forEvent:@"timeout"];  
[sm transitionFrom:opened to:opened forEvent:@"coin" withSel:@selector(returnCoin)];    


//Usage
[sm validate];  
[sm post:@"coin"];  
[sm post:@"pass"];

Decision example

//Create structure  
__weak id weakSelf = self;  
SMStateMachine *sm = [[SMStateMachine alloc] init];  
sm.globalExecuteIn = self; //execute all selectors on self object  
SMState *opened = [sm createState:@"open"];  
SMState *closed = [sm createState:@"closed"];  
SMDecision *isWorkTime = [sm createDecision:@"isWorkTime" withPredicateBoolBlock:^(){  
   return [weakSelf isWorkTime];  
}];  
sm.initialState = closed;  
[opened setEntrySelector:@selector(greenLightOn)];  
[closed setEntrySelector:@selector(redLightOn)];  
[sm transitionFrom:closed to:isWorkTime forEvent:@"coin"];  
[sm trueTransitionFrom:isWorkTime to:opened];  
[sm falseTransitionFrom:isWorkTime to:closed withSel:@selector(returnCoin)];  
[sm transitionFrom:opened to:closed forEvent:@"pass"];  
[sm transitionFrom:opened to:closed forEvent:@"timeout"];  
[sm transitionFrom:opened to:opened forEvent:@"coin" withSel:@selector(returnCoin)];  
[sm validate];  

//Usage
self.isWorkTime = NO;
self.returnCoinsCounter = 0;
[sm post:@"coin"];
STAssertEquals(1, self.returnCoinsCounter, nil);
self.isWorkTime = YES;
[sm post:@"coin"];
STAssertEquals(1, self.returnCoinsCounter, nil);
[sm post:@"coin"];
STAssertEquals(2, self.returnCoinsCounter, nil);`

Logging example

For enable logging you need to set the monitor property of fsm object to SMMonitorDelegate protocol implementation.
You can use the default SMMonitorNSLog implementation or write your own.

Attention! You need to have strong reference to you monitor object, because the fsm monitor property descrived as @property(nonatomic, weak) id <SMMonitorDelegate> monitor;

//strong ref to monitor object
SMMonitorNSLog *nsLogMonitor =[[SMMonitorNSLog alloc] initWithSmName:@"Turnstile"];
SMStateMachine *sm = [[SMStateMachine alloc] init]; 
//log to NSLog
sm.monitor = nsLogMonitor;
...

PS Feel free to contact me :)