Add javadoc and fixed some errors

Adapt queries to the updates made in TaskCreateUPreprocessing (delete  preprocessDataset attribute)

src/main/java/org/strep/domain/Task.java

@@ -56,8 +56,12 @@ public class Task implements Serializable {
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
 
+    // No caso de TaskCreateSDataset o que se fai é que o dataset que está en task actua como o dataset que hai que encher cos arquivos que se pasan no ficheiro zip. Básicamente sería un parámetro de E/S (entrada/salida). Este Dataset de salida instanciase no spring e despois échese no strep_service. 
     /**
-     * The dataset associated to this task
+     * The dataset associated to this task.  Depending on the type of task, the dataset will behave on different way.
+     * Preprocessing task (TaskCreateUPreprocessing) : This is an input dataset
+     * System task (TaskCreateSDataset) : This is an Input/output dataset. This dataset is filled with zip file content.
+     * Tune task (TaskCreateUDataset): Output dataset which contains the combination/filtering of instances made through executing the task
      */
     @ManyToOne(optional = true, fetch = FetchType.EAGER)
     @JoinColumn(name = "dataset_name")

src/main/java/org/strep/repositories/TaskRepository.java

@@ -116,8 +116,8 @@ public interface TaskRepository extends CrudRepository<Task, Long> {
      */
     @Query(value = "SELECT t "
             + "FROM TaskCreateUPreprocessing t, Dataset d "
-            + "WHERE d.name=t.preprocessDataset.name "
-            + "AND t.preprocessDataset.name<>?1 AND (d.access IN ('public','protected') OR d.author=?2) "
+            + "WHERE d.name=t.dataset.name "
+            + "AND t.dataset.name<>?1 AND (d.access IN ('public','protected') OR d.author=?2) "
             + "AND  t.state=?3")
     public ArrayList<TaskCreateUPreprocessing> findAllTaskCreateUPreprocessing(String datasetName, String username, String state);
 
@@ -170,7 +170,7 @@ public interface TaskRepository extends CrudRepository<Task, Long> {
      * @return a list with the preprocessing tasks of the dataset filtered by
      * state
      */
-    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.preprocessDataset=?1 AND t.state=?2 AND t.active='1'")
+    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.dataset.name=?1 AND t.state=?2 AND t.active='1'")
     public ArrayList<TaskCreateUPreprocessing> getActivePreprocessingTasks(Dataset dataset, String state);
 
     /**
@@ -182,7 +182,7 @@ public interface TaskRepository extends CrudRepository<Task, Long> {
      * @return a list with the preprocessing tasks of the dataset filtered by
      * state
      */
-    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.preprocessDataset=?1 AND t.state=?2")
+    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.dataset.name=?1 AND t.state=?2")
     public ArrayList<TaskCreateUPreprocessing> getPreprocessingTasks(Dataset dataset, String state);
 
     /**
@@ -193,7 +193,7 @@ public interface TaskRepository extends CrudRepository<Task, Long> {
      * @return a list with the preprocessing tasks of the dataset filtered by
      * state
      */
-    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.state=?1 ORDER BY t.preprocessDataset")
+    @Query(value = "SELECT t FROM TaskCreateUPreprocessing t WHERE t.state=?1 ORDER BY t.dataset.name")
     public ArrayList<TaskCreateUPreprocessing> getPreprocessingTasks(String state);
 
     /**