In this example, two cup radius selectors with different points of view are in conflict. This situation is shown in figure 7.6. The purpose of this example is to show the possibility of a strategy change during negotiation.
Figure 7.6: Value-value incompatibility
The cup radius selector with the style point of view is the current owner of the cup radius value entity, that is, the current value of the cup radius was set by the style selector. When the selector with the stability point of view is able to produce a value, it realizes that the current value is not compatible with the value it has produced, hence a conflict is detected. When asked for an alternative, the style selector would normally provide an alternative value, but in this case, it has run out of all alternatives. It switches its negotiation mode to a don't care mode which means that it does not care about the value of the cup radius, so the agent that initiated the conflict can choose any value. The style selector is designed to go into the don't care mode in such situations since the style point of view is not as important as the stability of the cup.
The excerpt follows:
Cup Radius Stability Selector: Conflict detected with Cup Radius Style Selector. Cup Radius Stability Selector: Ask Cup Radius Style Selector for an alternative value. Cup Radius Style Selector: No alternative values. Cup Radius Style Selector: Switching to dont care mode. Cup Radius Style Selector: Tell Cup Radius Stability Selector that I don't care about value of cup radius. Cup Radius Stability Selector: Ask Cup Radius Style Selector to retract the value of cup radius. Cup Radius Stability Selector: Conflict with Cup Radius Style Selector resolved. Cup Radius Style Selector: Value of cup radius retracted.