Application: gvSIG desktop

/**

 * gvSIG. Desktop Geographic Information System.

 *

 * Copyright (C) 2007-2013 gvSIG Association.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 3

 * of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 * For any additional information, do not hesitate to contact us

 * at info AT gvsig.com, or visit our website www.gvsig.com.

 */

package org.gvsig.remoteclient.taskplanning;

import java.util.Vector;

/**

 *  <p>

 *  You should write your own concrete Queue implementation to hold the tasks in

 *  a specific kind of queue.<br>

 *  </p>

 *  <p>

 *  Following the contract, you should also write a task planner that does what 

 *  you desire. Task planners are a concrete class of the ITaskPlanner that would 

 *  plannify which is the next, the previous,.. task to be done. However, if

 *  you don't want to write anything special, just guess a simple FIFO queue<br>

 *  </p>

 *  

 *  @author jaume dominguez faus - jaume.dominguez@iver.es

 *  @see ITaskPlanner

 */

public interface IQueue {

        /**

         * Adds a new task to the queue. The place where the new task will be put its

         * left to the concrete implementation of this interface.

         * @param IRunnableTask task

         */

        IRunnableTask put(IRunnableTask task);

        /**

         * Returns the next task by calling the task planner's nextTask() method.

         * @return IRunnableTask with the next task to be executed.

         */

        IRunnableTask take();

        /**

         * Returns true if the Queue has no (more) jobs to do.

         * @return

         */

        boolean isEmpty();

        /**

         * Returns the task planner currently defined by this queue.

         * @return ITaskPlanner

         */

        ITaskPlanner getTaskPlanner();

        /**

         * Sets the TaskPlanner that will decide which of the tasks in the queue will

         * be executed next. A null value should represent a FIFO planner. 

         * @param planner

         */

        void setTaskPlanner(ITaskPlanner planner);

        /**

         * Causes the execution of this queue to be paused. The task currently in execution

         * finishes and after it the planner will not issue more tasks until resume() is

         * invoked.

         */

        void pause();

        /**

         * Causes the execution of this queue to be resumed. The execution will continue

         * with the next task issued by the planner. It has no effect if the queue was not

         * paused yet. 

         */

        void resume();

        /**

         * Returns the set of tasks in a Vector (thread-safe).

         * @return Vector containing the tasks in this queue.

         */

        Vector getTasks();

}