Right... hasToken() always returns true in PN. The semantics of the model of computation is explained here:
http://ptolemy.eecs.berkeley.edu/publications/papers/95/processNets/ Edward Peter Reutemann wrote: >> I am trying to implement an actor that has two input ports-input and window. >> In the implementation, I want that the actor should execute different set of >> lines depending on if the tokens are present or not present at the window >> port. I am trying to do something like: >> if(window.hasToken()){ >> ArrayToken tokenD = (ArrayToken) input.get(0); >> System.out.println("There is a token at the window port"); >> } >> else >> System.out.println("There is no token at the window port"); >> >> I observer that when I use a PN director, the value of window.hasToken() is >> true even if there is no token at the window port. I actually used an >> arraytosequence actor to output the array tokens to my actor.So even if the >> input to arraytosequence is { }, my actor returns true for window.hasToken() >> and enters the "if" block. However after executing the first line of the >> "if" block, it stops i.e it does not print the next line. Can someone tell >> me why the PN director sets the value false when there is no token at the >> window port? > > Stumbled across that myself... > >>From what I understand: the PN domain always assumes that there are > tokens available in the queues, at one point or another (the > ptolemy.domains.pn.kernel.PNQueueReceiver class always returns "true" > in the "hasToken()" method). Only when using the "get(int)"-method of > the port it is attempted to obtain a token. If none is present at the > moment, then the method won't exit until a token shows up or the > workflow terminates. > > Cheers, Peter -------------- next part -------------- A non-text attachment was scrubbed... Name: eal.vcf Type: text/x-vcard Size: 351 bytes Desc: not available URL: <http://mercury.nceas.ucsb.edu/kepler/pipermail/kepler-users/attachments/20091021/6dd3880c/attachment.vcf>
