Execute testcase: package org.optaplanner.core.impl.domain.solution.cloner; import junit.framework.TestCase; import org.optaplanner.core.api.domain.entity.PlanningEntity; import org.optaplanner.core.api.domain.solution.PlanningEntityCollectionProperty; import org.optaplanner.core.api.domain.solution.Solution; import org.optaplanner.core.api.domain.valuerange.ValueRangeProvider; import org.optaplanner.core.api.domain.variable.PlanningVariable; import org.optaplanner.core.api.domain.variable.PlanningVariableGraphType; import org.optaplanner.core.api.score.buildin.simple.SimpleScore; import org.optaplanner.core.impl.domain.solution.descriptor.SolutionDescriptor; import java.util.ArrayList; import java.util.Collection; import java.util.List; /** * Description: <br> * <p> * Date: 07.04.15<br> * </p> */ public class FieldAccessingSolutionClonerTest extends TestCase { FieldAccessingSolutionCloner cloner; public static abstract class AbstractTestSolution implements Solution<SimpleScore> { List<TestVehicle> vehicles; private SimpleScore score; List<TestWorkload> workloads; @Override public SimpleScore getScore() { return score; } @Override public void setScore(SimpleScore score) { this .score = score; } @Override public Collection<?> getProblemFacts() { return vehicles; } @PlanningEntityCollectionProperty @ValueRangeProvider(id = "workloadsRange" ) public List<TestWorkload> getWorkloads() { return workloads; } @ValueRangeProvider(id = "vehiclesRange" ) public List<TestVehicle> getVehicles() { return vehicles; } } public static class TestSolution extends AbstractTestSolution { } public static abstract class AbstractTestWorkload implements TestStandstill { String id; private TestStandstill previousStandstill; @PlanningVariable(graphType = PlanningVariableGraphType.CHAINED, valueRangeProviderRefs = { "vehiclesRange" , "workloadsRange" }) public TestStandstill getPreviousStandstill() { return previousStandstill; } public void setPreviousStandstill( TestStandstill previousStandstill) { this .previousStandstill = previousStandstill; } public String toString() { return getClass().getSimpleName() + "{id=" + id + "}" ; } } @PlanningEntity public static class TestWorkload extends AbstractTestWorkload { } public static class TestVehicle implements TestStandstill { String id; public String toString() { return getClass().getSimpleName() + "{id=" + id + "}" ; } } public interface TestStandstill { } public void testCloneSolutionWithInheritedVariables() { SolutionDescriptor descriptor = new SolutionDescriptor(TestSolution.class); cloner = new FieldAccessingSolutionCloner(descriptor); TestSolution solution = createTestSolution(); TestSolution clone = (TestSolution) cloner.cloneSolution(solution); assertTrue(clone != null ); assertTrue(clone != solution); // a clone has been created that is not the same instance as the original assertTrue(clone.workloads != solution.workloads); // the collection of workloads must be a clone... assertTrue(clone.workloads.size() == solution.workloads.size()); // ... of same size assertTrue(clone.workloads.get(0) != solution.workloads.get(0)); // ... containing clones (deep cloned) assertTrue( clone.workloads.get(0).getPreviousStandstill() == clone.workloads.get(1)); // ... and correct cross-refs assertTrue(clone.workloads.get(1).getPreviousStandstill() == clone.vehicles.get(0)); } private TestSolution createTestSolution() { TestSolution s = new TestSolution(); s.vehicles = new ArrayList<>(); s.vehicles.add( new TestVehicle()); s.workloads = new ArrayList<>(); s.workloads.add( new TestWorkload()); s.workloads.add( new TestWorkload()); s.workloads.get(0).setPreviousStandstill(s.workloads.get(1)); s.workloads.get(1).setPreviousStandstill(s.vehicles.get(0)); s.workloads.get(0).id = "W1" ; s.workloads.get(1).id = "W2" ; s.vehicles.get(0).id = "V1" ; return s; } }