Sorry, I made a mistake in copying the code. The second datalink is in the
element Second like this:
<site>
<arrival destid="Start"/>
<element id="Start" url="/start" implementation="com.test.Start">
<exit name="started" />
<flowlink srcexit="started" destid="Second">
<datalink srcoutput="counter" destinput="counter"/>
</flowlink>
</element>
<element id="Second" url="/second" implementation="com.test.Second">
<input name="counter" />
<datalink srcoutput="counter" destinput="counter" destid="Second" />
<submission name="increase">
<param name="increment" />
</submission>
</element>
Jean-Marie Galliot wrote:
>
> Hi,
>
> I have this simple site :
>
> <site>
> <arrival destid="Start"/>
>
> <element id="Start" url="/start" implementation="com.test.Start">
>
> <exit name="started" />
> <flowlink srcexit="started" destid="Second">
> <datalink srcoutput="counter" destinput="counter"/>
> </flowlink>
> <datalink srcoutput="counter" destinput="counter" destid="Second"
> />
> </element>
>
> <element id="Second" url="/second" implementation="com.test.Second">
> <input name="counter" />
> <submission name="increase">
> <param name="increment" />
> </submission>
> </element>
>
> </site>
>
> And this is the implementation of the element Start:
>
> public class Start extends Element {
>
> public void initialize() {
> System.out.println("Start.initialize");
> }
>
> public int getCounter() {
> System.out.println("Start.getCounter() = 3");
> return 3;
> }
>
> public void processElement() {
> System.out.println("Start.processElement()");
> exit("started");
> }
> }
>
> The output trace is:
> Start.initialize
> Start.processElement()
> Start.getCounter() = 3
> Start.getCounter() = 3
> Start.getCounter() = 3
> Guess.setCounter(3)
> Guess.processElement()
>
> Could you explain why getCounter() is called three times?
>
> Also, what I am trying to do is having this element Start initializing and
> transmitting a value to element Second.
> For the time being it'a a simple integer but it will be eventually a bean.
>
> Then, the subsequent requests will be processed by element Second. At each
> request, the value originally initialized by the element Start will
> evolve, so It will use a datalink from element Second to itself to keep
> the state like you suggested in the example : statefull components.
>
> But the problem is :
>
> Apparently, each time the element Second is processed (and not only the
> first time) the method getCounter of element Start is called and the value
> is set into element Second.
>
> I can understand why but how can we accomplish this simple behavior :
>
> Element second is initialized with a value from Element Start. But after
> that, the value is modified iteratively in element Second by the very
> process of subsequent requests, without the value being reinitialized each
> time by the element Start?
>
> I can imagine two datalinks with two distincts variables. Then element
> Second has to decide that the second variable (the one coming from
> himself) has precedence over the one coming from element Start. But it
> looks unnatural.
>
> Can you help?
>
> Tks
>
--
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