Fix issue when moving a task with an assignment function.

Now assignment function is applied again in destination.

For StretchesFunction a new method was needed in order to update
stretches dates in destination.
Actually, dates shouldn't be stored in Stretch class. This should be
changed in the future.

FEA: ItEr75S23FixAllocationModel

navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/AssignmentFunction.java

@@ -23,6 +23,8 @@ package org.navalplanner.business.planner.entities;
 
 import static org.navalplanner.business.i18n.I18nHelper._;
 
+import java.util.List;
+
 import org.navalplanner.business.common.BaseEntity;
 
 /**
@@ -36,6 +38,24 @@ public class AssignmentFunction extends BaseEntity {
         return create(new AssignmentFunction());
     }
 
+    /**
+     * This method goes over the {@link ResourceAllocation} list and apply the
+     * assignment function if it is defined.
+     *
+     * @param resourceAllocations
+     *            List of {@link ResourceAllocation}
+     */
+    public static void applyAssignmentFunctionsIfAny(
+            List<ResourceAllocation<?>> resourceAllocations) {
+        for (ResourceAllocation<?> resourceAllocation : resourceAllocations) {
+            AssignmentFunction assignmentFunction = resourceAllocation
+                    .getAssignmentFunction();
+            if (assignmentFunction != null) {
+                assignmentFunction.applyTo(resourceAllocation);
+            }
+        }
+    }
+
     public AssignmentFunction() {
 
     }

navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/StretchesFunction.java

@@ -29,7 +29,6 @@ import java.math.RoundingMode;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 
@@ -375,6 +374,7 @@ public class StretchesFunction extends AssignmentFunction {
         if (resourceAllocation.getFirstNonConsolidatedDate() == null) {
             return;
         }
+        updateStretchesDates(resourceAllocation);
         taskEndDate = getTaskEndDate(resourceAllocation);
         getDesiredType().applyTo(resourceAllocation, this);
         type = getDesiredType();
@@ -453,4 +453,27 @@ public class StretchesFunction extends AssignmentFunction {
         this.taskEndDate = taskEndDate;
     }
 
+    /**
+     * {@link Stretch} is storing date in an attribute. When a task is moved
+     * these dates have to be updated.
+     *
+     * FIXME: Maybe in the future we could remove these dates as they could be
+     * calculated from task information.
+     */
+    private void updateStretchesDates(ResourceAllocation<?> resourceAllocation) {
+        Task task = resourceAllocation.getTask();
+
+        long startDate = task.getStartDate().getTime();
+        long endDate = task.getEndDate().getTime();
+
+        for (Stretch stretch : stretches) {
+            // startDate + (percentage * (endDate - startDate))
+            long stretchDate = startDate
+                    + stretch.getLengthPercentage()
+                            .multiply(new BigDecimal(endDate - startDate))
+                            .longValue();
+            stretch.setDate(new LocalDate(stretchDate));
+        }
+    }
+
 }

navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/Task.java

@@ -825,6 +825,8 @@ public class Task extends TaskElement implements ITaskPositionConstrained {
         default:
             throw new RuntimeException("cant handle: " + calculatedValue);
         }
+
+        AssignmentFunction.applyAssignmentFunctionsIfAny(toBeModified);
     }
 
     private void markAsUnsatisfied(