/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.activiti.engine.task;

/**
 * Allows programmatic querying of {@link Task}s;
 * 
 * @author Joram Barrez
 * @author Falko Menge
 * @author Tijs Rademakers
 */
public interface TaskQuery extends TaskInfoQuery<TaskQuery, Task> {

  /** Only select tasks which don't have an assignee. */
  TaskQuery taskUnassigned();
  
  /** @see {@link #taskUnassigned} */
  @Deprecated
  TaskQuery taskUnnassigned();
  
  /** Only select tasks with the given {@link DelegationState}. */
  TaskQuery taskDelegationState(DelegationState delegationState);

  /** Select tasks that has been claimed or assigned to user or waiting to claim by user (candidate user or groups).
   *  You can invoke {@link #taskCandidateGroupIn(List)} to include tasks that can be claimed by a user in the given groups
   *  while set property <strong>dbIdentityUsed</strong> to <strong>false</strong> in process engine configuration
   *  or using custom session factory of GroupIdentityManager.
   */
  TaskQuery taskCandidateOrAssigned(String userIdForCandidateAndAssignee);
  
  /** Only select tasks that have no parent (i.e. do not select subtasks). */
  TaskQuery excludeSubtasks();
  
  /**
   * Only selects tasks which are suspended, because its process instance was suspended.
   */
  TaskQuery suspended();
  
  /**
   * Only selects tasks which are active (ie. not suspended)
   */
  TaskQuery active();
  
  
  // ordering ////////////////////////////////////////////////////////////
  
  
  /** 
   * Order by due date (needs to be followed by {@link #asc()} or {@link #desc()}).
   * This will use the default handling of null values of the used database.
   * 
   *  @deprecated Use orderByTaskDueDate() instead
   */
  TaskQuery orderByDueDate();
  

}