diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/IWorkerDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/IWorkerDAO.java
index b2e31818d..7b1e0f08f 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/IWorkerDAO.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/IWorkerDAO.java
@@ -20,11 +20,12 @@
 
 package org.navalplanner.business.resources.daos;
 
+import java.util.Collection;
 import java.util.List;
 
 import org.navalplanner.business.common.daos.IGenericDAO;
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
-import org.navalplanner.business.resources.entities.Criterion;
+import org.navalplanner.business.resources.entities.ICriterion;
 import org.navalplanner.business.resources.entities.Worker;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -49,7 +50,7 @@ public interface IWorkerDAO extends IGenericDAO<Worker, Long> {
      * @return
      */
     @SuppressWarnings("unchecked")
-    List<Worker> findByNameAndCriterions(String name, List<Criterion> criterions);
+    List<Worker> findByNameAndCriterions(String name, Collection<? extends ICriterion> criterions);
 
     /**
      * Returns workers which name/NIF partially matches with name
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/WorkerDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/WorkerDAO.java
index 0c7896ff1..0d25e63f7 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/WorkerDAO.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/resources/daos/WorkerDAO.java
@@ -21,14 +21,14 @@
 package org.navalplanner.business.resources.daos;
 
 import java.util.ArrayList;
-import java.util.HashSet;
+import java.util.Collection;
 import java.util.List;
 
 import org.hibernate.Criteria;
 import org.hibernate.criterion.Restrictions;
 import org.navalplanner.business.common.daos.GenericDAOHibernate;
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
-import org.navalplanner.business.resources.entities.Criterion;
+import org.navalplanner.business.resources.entities.ICriterion;
 import org.navalplanner.business.resources.entities.Worker;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.context.annotation.Scope;
@@ -69,7 +69,7 @@ public class WorkerDAO extends GenericDAOHibernate<Worker, Long>
     @SuppressWarnings("unchecked")
     @Override
     public List<Worker> findByNameAndCriterions(String name,
-            List<Criterion> criterions) {
+            Collection<? extends ICriterion> criterions) {
 
         // Find workers by name
         List<Worker> workers;
@@ -87,7 +87,7 @@ public class WorkerDAO extends GenericDAOHibernate<Worker, Long>
         // Filter by criterion
         final List<Worker> result = new ArrayList<Worker>();
         for (Worker worker : workers) {
-            if (worker.satisfiesCriterions(new HashSet(criterions))) {
+            if (worker.satisfiesCriterions(criterions)) {
                 result.add(worker);
             }
         }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionCompounder.java b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionCompounder.java
index 5410b2f76..d07d745bb 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionCompounder.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/CriterionCompounder.java
@@ -36,7 +36,8 @@ public class CriterionCompounder {
         return new CriterionCompounder();
     }
 
-    public static CriterionCompounder buildAnd(List<ICriterion> criterions) {
+    public static CriterionCompounder buildAnd(
+            Collection<? extends ICriterion> criterions) {
         CriterionCompounder compounder = new CriterionCompounder();
         for (ICriterion criterion : criterions) {
             compounder = compounder.and(criterion);
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/Worker.java b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/Worker.java
index 7fd86bb4b..e26703799 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/Worker.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/resources/entities/Worker.java
@@ -21,7 +21,7 @@
 package org.navalplanner.business.resources.entities;
 
 import java.util.ArrayList;
-import java.util.Set;
+import java.util.Collection;
 
 import org.hibernate.validator.NotEmpty;
 import org.hibernate.validator.NotNull;
@@ -101,7 +101,8 @@ public class Worker extends Resource {
         this.nif = nif;
     }
 
-    public boolean satisfiesCriterions(Set<Criterion> criterions) {
+    public boolean satisfiesCriterions(
+            Collection<? extends ICriterion> criterions) {
         ICriterion compositedCriterion = CriterionCompounder.buildAnd(
                 new ArrayList<ICriterion>(criterions)).getResult();
         return compositedCriterion.isSatisfiedBy(this);