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Difference between revisions of "VIATRA/DSE/UserGuide/Strategy"
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| − | This method is called every time a new state is traversed. Returning anything but null makes the engine to mark the state as a goal state. Default implementation ( | + | This method is called every time a new state is traversed. Returning anything but null makes the engine to mark the state as a goal state. Default implementation (''CheckAllGoals'') checks all the given goal patterns and returns an empty map if all of them is satisfied. |
Descend this interface if the "AND" logic between the goals is not suitable, a goal cannot be defined using IncQuery, or measurements between goal states is necessary. In the last case return a map filled with the measurements and also override the implementation of the [[VIATRA/DSE/UserGuide/SolutionStore|SolutionStore]] to compare the goal states and store only the best ones. | Descend this interface if the "AND" logic between the goals is not suitable, a goal cannot be defined using IncQuery, or measurements between goal states is necessary. In the last case return a map filled with the measurements and also override the implementation of the [[VIATRA/DSE/UserGuide/SolutionStore|SolutionStore]] to compare the goal states and store only the best ones. | ||
Revision as of 07:30, 1 October 2014
Contents
Using the Strategy class
In this section the components of the Strategy class are explained including the following four interfaces and its built in implementataions:
- ICheckConstraints
- ICheckGoalState
- ISolutionFound
- INextTransition
Its only responsibility is the call delegation to the four interfaces. Implementation of these interfaces can be set via simple set methods. The only exception is the INextTransition interface which is a required parameter in the constructor.
ICheckConstraints
This interface has only one method and it is responsible for deciding whether the current state satisfies the global constraints returning true if the answer is yes:
boolean checkConstraints(ThreadContext context);
This method called every time a new state is traversed and if it returns false the current state will be marked as "shouldn't explore further" for the traversal strategy. Default implementation of this interface is the CheckAllConstraints class, which simply checks all the given constraints and return false if at least one constraint is failed to be satisfied.
Override this implementation if the "AND" logic between the constraints is not suitable or a global constraint cannot be defined using IncQuery.
ICheckGoalState
Implementation of this interface is responsible for determining if the current state is a potential goal state. It declares the next method:
Map<String, Double> isGoalState(ThreadContext context);
This method is called every time a new state is traversed. Returning anything but null makes the engine to mark the state as a goal state. Default implementation (CheckAllGoals) checks all the given goal patterns and returns an empty map if all of them is satisfied.
Descend this interface if the "AND" logic between the goals is not suitable, a goal cannot be defined using IncQuery, or measurements between goal states is necessary. In the last case return a map filled with the measurements and also override the implementation of the SolutionStore to compare the goal states and store only the best ones.