From dcb97a7f59c949d8e85c40ec5aaf66458f0dcb02 Mon Sep 17 00:00:00 2001
From: Jan Vales <jan@jvales.net>
Date: Wed, 28 Mar 2018 20:36:34 +0200
Subject: [PATCH] [1.2.3a] oidaaaa... tag is vorbei :/

---
 .../ass1/jpa/dao/impl/MaterialServerDAO.java  | 22 +++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/ass1-jpa/src/main/java/dst/ass1/jpa/dao/impl/MaterialServerDAO.java b/ass1-jpa/src/main/java/dst/ass1/jpa/dao/impl/MaterialServerDAO.java
index d1ff753..036e520 100644
--- a/ass1-jpa/src/main/java/dst/ass1/jpa/dao/impl/MaterialServerDAO.java
+++ b/ass1-jpa/src/main/java/dst/ass1/jpa/dao/impl/MaterialServerDAO.java
@@ -3,10 +3,18 @@ package dst.ass1.jpa.dao.impl;
 import dst.ass1.jpa.dao.IMaterialServerDAO;
 import dst.ass1.jpa.model.ICourse;
 import dst.ass1.jpa.model.IMaterialServer;
+import dst.ass1.jpa.model.impl.Lesson;
+import dst.ass1.jpa.model.impl.Material;
 import dst.ass1.jpa.model.impl.MaterialServer;
+import dst.ass1.jpa.util.Constants;
 
 import javax.persistence.EntityManager;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Join;
+import javax.persistence.criteria.Root;
 import java.util.Collection;
+import java.util.List;
 
 public class MaterialServerDAO extends GenericDAO<MaterialServer, IMaterialServer> implements IMaterialServerDAO {
     public MaterialServerDAO(EntityManager em) {
@@ -15,7 +23,17 @@ public class MaterialServerDAO extends GenericDAO<MaterialServer, IMaterialServe
 
     @Override
     public Collection<IMaterialServer> findMaterialServersForCourse(ICourse course) {
-        return null;
-    }
+        CriteriaBuilder b = em.getCriteriaBuilder();
+        CriteriaQuery<IMaterialServer> q = b.createQuery(IMaterialServer.class);
+
+        Root<MaterialServer> root = q.from(MaterialServer.class);
+        Join<MaterialServer, Material> materials = root.join(Constants.A_MATERIALS);
+        Join<Material, Lesson> lessons = materials.join(Constants.M_MATERIAL_LESSON);
 
+        q.select(root).distinct(true);
+        if (course != null) q.where(lessons.in(course.getLessons()));
+
+        List<IMaterialServer> a = em.createQuery(q).getResultList();
+        return a;
+    }
 }
-- 
2.43.0