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--- developer:sequencer:exception_handling [2015/02/10 17:22] – external edit 127.0.0.1
+++ developer:sequencer:exception_handling [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
-======Error Handler Usage======
-The error handler is also a sequence. But it will be used in case of an exception, so the user knows that it is a recovery pass.
-To create a new error handler, you have to derive from the class //ErrorHandler// built in the framework.
-<code c>
-class MyErrorHandlerA : public eeros::sequencer::ErrorHandler
-</code>
-Then you can implement the //run()// methode including all the functionality to solve the problem causing the exception or to restart the system.
-<code c>
-void MyErrorHandlerA::run(){
-	Reset();
-	Referencing();
-	RestartSequence();
-}
-</code>
-This //run()// methode will be called in the base class //Sequence// of the framework if an exception was thrown. The exception is a //SequenceException// of the framework, it can be thrown at any time.
-e.g.:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-		static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException),
-		static_cast<eeros::sequencer::Sequence::method>(&MySequence::Initialised),
-		errorHandlerA, false, true, "TestException");
-</code>
-The constructor has following parameters:
-<code c>
-SequenceException(Sequence* seqCause, Sequence::method cause, Sequence::method next,
-		ErrorHandler* error, bool toBegin, bool goToNext, std::string reason);
-</code>
-__Parameter //seqCause// und //cause//:__ The exception occured in the method //cause// of the sequence //seqCause//.
-__Parameter //next//:__ If //toBegin// is false and //goToNext// true, then this is the next method on which the sequence continues, after error handling has finished!
-__Parameter //toBegin//:__ Is //toBegin// true and //goToNext// false, so the sequence is restarted. (please refer also to the parameter //next//).
-Please note: //toBegin// and //goToNext// can not be true in the same exception!
-__Parameter //error//:__ //error// is the //ErrorHandler//, which defines the behaviour on an exception.
-__Parameter //goToNext//:__ Is //toBegin// false and //goToNext// true, then the sequence continues at the //next// methode after the error handling.
-__Parameter reason:__ error message
-=====Case 1=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase1.png?600 | //Exception Flow Case 1//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, true, false, "TestException");
-</code>
-=====Case 2=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase2.png?600 | //Exception Flow Case 2.1//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, false, false, "TestException");
-</code>
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase2b.png?600 | //Exception Flow Case 2.2//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException),
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::Homed),
-	errorHandlerA, false, true, "TestException");
-</code>
-=====Case 3=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase3.png?600 | //Exception Flow Case 3//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>&MySequence::MoveException), 0,
-	errorHandlerA, true, false, "TestException");
-</code>
-The //ErrorHandlerA// calls the second error handler //ErrorHandlerB//.
-<code c>
-MyErrorHandlerB* errorHandlerB =
-	dynamic_cast<MyErrorHandlerB*>(eeros::sequencer::ErrorHandler::getErrorHandler("MyErrorHandlerB"));
-if(!errorHandlerB){
-	errorHandlerB = new MyErrorHandlerB("MyErrorHandlerB");
-}
-errorHandlerB->run();
-</code>
-=====Case 4=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase4.png?600 | //Exception Flow Case 4.1//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, false, false, "TestException");
-</code>
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase4b.png?600 | //Exception Flow Case 4.2//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException),
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::Homed),
-	errorHandlerA, false, true, "TestException");
-</code>
-=====Case 5=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase5.png?600 | //Exception Flow Case 5//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, true, false, "TestException");
-</code>
-In the case, which the sequencer will be restarted on an exception, the sub-sequencer could be kept on running state or it could also be restarted. This can be choosen by the user.
-The code below shows how you can solve it.
-<code c>
-MySequencer* subSequencer = dynamic_cast<MySequencer*>
-	(eeros::sequencer::Sequencer::getMainSequencer()->findSequencer("SubSequencer"));
-bool seqIsNew = false;
-if(!subSequencer){
-	//use pointer to leave the object in memory!!
-	//without pointer the objetct will be destroyed.
-	subSequencer = new MySequencer("SubSequencer");
-	seqIsNew = true;
-	//callerThread for NonBlocking Sub Sequence is a new Sequencer
-	//please take attention, if this Object looses scope, so it will be deleted!!
-	//that's why you should use a pointer to allocate memory!!
-	//else the pointer in the Executor runnables list of the Sequencer will point to nowhere!!
-}
-NonBlockingSubSequence* subSequence = dynamic_cast<NonBlockingSubSequence*>
-	(eeros::sequencer::Sequence::getSequence("NonBlockingSubSequence"));
-if(!subSequence){
-	//MyNonBlockingSubSequence is a Runnable!!
-	subSequence = new NonBlockingSubSequence("NonBlockingSubSequence", *subSequencer);
-	if(seqIsNew){
-		//now we start the Thread of the subSequencer
-		subSequencer->start();
-	}
-}
-try{
-	if(!seqIsNew && restartSequencer && subSequencer &&
-			subSequencer->getStatus() != eeros::kStopped){
-		eeros::ExecutorService::waitForSequenceEnd(subSequencer);
-		subSequencer->start();
-	}
-}catch(char *str){
-}
-</code>
-If restartSequencer is true, so the sub-sequencer will be restarted  and you have to wait for the termination of the running sub-sequencer.
-If restartSequencer is false, so the sub-sequencer runs until he finished, without restarting.
-=====Case 6=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase6.png?600 | //Exception Flow Case 6.1//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, false, false, "TestException");
-</code>
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase6b.png?600 | //Exception Flow Case 6.2//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException),
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::Homed),
-	errorHandlerA, false, true, "TestException");
-</code>
-=====Case 7=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase7.png?600 | //Exception Flow Case 7//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, true, false, "TestException");
-</code>
-=====Case 8=====
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase8.png?600 | //Exception Flow Case 8.1//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException), 0,
-	errorHandlerA, false, false, "TestException");
-</code>
-[{{ :eeros:developer_documentation:sequencer:errorhandlercase8b.png?600 | //Exception Flow Case 8.2//}}]
-exception:
-<code c>
-throw new eeros::sequencer::SequenceException(this,
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::MoveException),
-	static_cast<eeros::sequencer::Sequence::method>(&MySequence::Homed),
-	errorHandlerA, false, true, "TestException");
-</code>