how do I resolve this problem use optaplanner - optaplanner

Question

Here is a simple problem, some products, every product has a quantity, these products must be produced by some factories, and every factory has a max quantity ability, the product and the factory is a many to many relationship
Factory.class is
#Data
#AllArgsConstructor
public class Factory {
private String name;
private String code;
private Integer qty;
}
Product.class is
#Data
#AllArgsConstructor
public class Product {
private String name;
private String spuCode;
private Integer qty;
}
ProblemAndSolution.class is
#PlanningSolution
#Data
public class ProblemAndSolution {
#ProblemFactCollectionProperty
#ValueRangeProvider(id = "productList")
private List<Product> productList;
#ProblemFactCollectionProperty
#ValueRangeProvider(id = "factoryList")
private List<Factory> factoryList;
private List<ProductFactoryAssignment> solutionList;
#PlanningScore
private HardSoftScore score;
#PlanningEntityCollectionProperty
public List<ProductFactoryAssignment> getSolutionList() {
return solutionList;
}
}
ProductFactoryAssignment.class is
#Data
#PlanningEntity
#AllArgsConstructor
public class ProductFactoryAssignment {
#PlanningVariable(valueRangeProviderRefs = "productList")
private Product product;
#PlanningVariable(valueRangeProviderRefs = "factoryList")
private Factory factory;
private Integer qty;
public Product getProduct() {
return product;
}
public Factory getFactory() {
return factory;
}
public Integer getQty() {
return qty;
}
#Override
public String toString() {
return "product is：" + product.getName() + "，factory is："+factory.getName()+"，qty is："+qty;
}
}
ProductFactoryConstraintProvider.class is
public class ProductFactoryConstraintProvider implements ConstraintProvider {
#Override
public Constraint[] defineConstraints(ConstraintFactory constraintFactory) {
return new Constraint[] {
// Hard constraints
productQtyConflict(constraintFactory),
factoryQtyConflict(constraintFactory)
};
}
Constraint productQtyConflict(ConstraintFactory constraintFactory) {
return constraintFactory
.forEach(ProductFactoryAssignment.class)
.groupBy(ProductFactoryAssignment::getProduct, ConstraintCollectors.sum(ProductFactoryAssignment::getQty))
.filter((product, poQty) -> poQty >= product.getQty())
.penalize(HardSoftScore.ONE_HARD)
.asConstraint("error");
}
Constraint factoryQtyConflict(ConstraintFactory constraintFactory) {
return constraintFactory
.forEach(ProductFactoryAssignment.class)
.groupBy(ProductFactoryAssignment::getFactory, ConstraintCollectors.sum(ProductFactoryAssignment::getQty))
.filter((factory, poQty) -> poQty <= factory.getQty())
.penalize(HardSoftScore.ONE_HARD)
.asConstraint("error");
}
}
main is
public static void main(String[] args) {
SolverFactory<ProblemAndSolution> solverFactory = SolverFactory.create(new SolverConfig()
.withSolutionClass(ProblemAndSolution.class)
.withEntityClasses(ProductFactoryAssignment.class)
.withConstraintProviderClass(ProductFactoryConstraintProvider.class)
// The solver runs only for 5 seconds on this small dataset.
// It's recommended to run for at least 5 minutes ("5m") otherwise.
.withTerminationSpentLimit(Duration.ofSeconds(5)));
// Load the problem
ProblemAndSolution problem = new ProblemAndSolution();
List<Product> productList = Lists.newArrayList(
new Product("product1", "001", 10000),
new Product("product2", "002", 5000)
);
List<Factory> factoryList = Lists.newArrayList(
new Factory("factory1", "001", 3000),
new Factory("factory2", "002", 6000),
new Factory("factory3", "003", 7000),
new Factory("factory4", "004", 4000),
new Factory("factory5", "005", 3000)
);
problem.setProductList(productList);
problem.setFactoryList(factoryList);
problem.setSolutionList(Lists.newArrayList());
// Solve the problem
Solver<ProblemAndSolution> solver = solverFactory.buildSolver();
ProblemAndSolution solution = solver.solve(problem);
System.out.println(solution);
}
solution's solutionList is empty, how to get a result like
product1, factory1, 3000
product1, factory3, 7000
product2, factory2, 5000

Answer 1

You have not filled the solution list with any planning entities, therefore OptaPlanner does not have anything to solve. Introduce some planning entity instances, and OptaPlanner will assign their planning variables with the values from the factory and product lists.
(Note: I'm not saying the domain model is correct or that it will do what you want it to do. I'm just saying that, without planning entities, it will not do anything at all.)