Task.h

00001 #ifndef _TASK_H_
00002 #define _TASK_H_
00003 
00004 #include "mbed.h"
00005 
00006 /**
00007  * @author Christian Burri
00008  *
00009  * @copyright Copyright (c) 2013 HSLU Pren Team #1 Cruising Crêpe
00010  * All rights reserved.
00011  *
00012  * @brief
00013  * The <code>Task</code> class allows to install periodic, time-triggered
00014  * tasks. An example of a simple user-defined task is given below:
00015  * <pre><code>
00016  * class MyTask : public Task {
00017  *   public:
00018  *     void run();
00019  * };
00020  *
00021  * void MyTask::run() {
00022  *   <span style="color:#FF0000">// code to be executed periodically</span>
00023  * }
00024  * </code></pre>
00025  * This task can then be created and started as follows:
00026  * <pre><code>
00027  * MyTask myTask(0.1);    <span style="color:#FF0000">// period in seconds</span>
00028  * myTask.start();
00029  * ...
00030  *
00031  * myTask.stop();
00032  * </code></pre>
00033  * 
00034  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
00035  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00036  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00037  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00038  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
00039  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
00040  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00041  */
00042 class Task
00043 {
00044 
00045 private:
00046 
00047     /** specifiying the interval in seconds */
00048     float       period;
00049     /** The Ticker interface is used to setup a recurring interrupt to
00050      *  repeatedly call a function at a specified rate.
00051      */
00052     Ticker      ticker;
00053 
00054 public:
00055 
00056     /**
00057      * Creates a task object with a given period.
00058      * @param period the period of this task in seconds.
00059      */
00060     Task(float period);
00061 
00062     virtual ~Task();
00063 
00064     /**
00065      * Gets the period of this task.
00066      * @return the period in seconds.
00067      */
00068     float           getPeriod();
00069 
00070     /**
00071      * Starts this task.
00072      */
00073     void            start();
00074 
00075     /**
00076      * Stops this task.
00077      */
00078     void            stop();
00079 
00080     /**
00081      * This method needs to be implemented by a user task.
00082      */
00083     virtual void    run();
00084 };
00085 
00086 #endif