naming conventions of other examples: *Difficulty/Strength

src/main/java/org/optaplanner/examples/projectscheduling/domain/Allocation.java

@@ -6,11 +6,11 @@
 import org.optaplanner.core.api.domain.value.ValueRange;
 import org.optaplanner.core.api.domain.value.ValueRangeType;
 import org.optaplanner.core.api.domain.variable.PlanningVariable;
-import org.optaplanner.examples.projectscheduling.domain.solver.AllocationComparator;
+import org.optaplanner.examples.projectscheduling.domain.solver.AllocationDifficultyComparator;
 import org.optaplanner.examples.projectscheduling.domain.solver.JobModeComparator;
-import org.optaplanner.examples.projectscheduling.domain.solver.StartDateComparator;
+import org.optaplanner.examples.projectscheduling.domain.solver.StartDateStrengthComparator;
 
-@PlanningEntity(difficultyComparatorClass = AllocationComparator.class)
+@PlanningEntity(difficultyComparatorClass = AllocationDifficultyComparator.class)
 public class Allocation {
 
     private final Job job;
@@ -49,7 +49,7 @@ public Collection<JobMode> getJobModes() {
         return this.job.getJobModes();
     }
 
-    @PlanningVariable(strengthComparatorClass = StartDateComparator.class)
+    @PlanningVariable(strengthComparatorClass = StartDateStrengthComparator.class)
     @ValueRange(planningEntityProperty = "startDates", type = ValueRangeType.FROM_PLANNING_ENTITY_PROPERTY)
     public Integer getStartDate() {
         return this.startDate;

src/main/java/org/optaplanner/examples/projectscheduling/domain/solver/AllocationDifficultyComparator.java

@@ -0,0 +1,22 @@
+package org.optaplanner.examples.projectscheduling.domain.solver;
+
+import java.util.Comparator;
+
+import org.optaplanner.examples.projectscheduling.domain.Allocation;
+
+public class AllocationDifficultyComparator implements Comparator<Allocation> {
+
+    @Override
+    public int compare(final Allocation a, final Allocation b) {
+        final int aSize = a.getJob().getRecursiveSuccessors().size();
+        final int bSize = b.getJob().getRecursiveSuccessors().size();
+        if (aSize < bSize) {
+            return -1;
+        } else if (aSize == bSize) {
+            return 0;
+        } else {
+            return 1;
+        }
+    }
+
+}

src/main/java/org/optaplanner/examples/projectscheduling/domain/solver/StartDateStrengthComparator.java

@@ -0,0 +1,12 @@
+package org.optaplanner.examples.projectscheduling.domain.solver;
+
+import java.util.Comparator;
+
+public class StartDateStrengthComparator implements Comparator<Integer> {
+
+    @Override
+    public int compare(Integer a, Integer b) {
+        return a.compareTo(b);
+    }
+
+}