source: gssim/trunk/src/example/localplugin/FCFSLocalPlugin.java @ 93

package example.localplugin;

import gridsim.Gridlet;

import java.util.List;
import java.util.Properties;

import schedframe.scheduling.Queue;
import schedframe.scheduling.TaskInterface;
import schedframe.scheduling.events.SchedulingEvent;
import schedframe.scheduling.plugin.local.ResourceUnitsManagerInterface;

/**
 * 
 * @author Marcin Krystek
 *
 */
public class FCFSLocalPlugin extends BaseLocalPlugin {

        
        public FCFSLocalPlugin(){
        }
        
        public void schedule(SchedulingEvent event,
                        List<? extends TaskInterface<?>> inExecution,
                        List<? extends Queue<? extends TaskInterface<?>>> queues,
                        ResourceUnitsManagerInterface unitsManagerInterface) {
                
                // do this trick to make add() method available
                List <TaskInterface<?>> execute = (List<TaskInterface<?>>) inExecution;
                
                // chose the events types to serve. 
                // Different actions for different events are possible.
                switch(event.getType()){
                        case START_TASK_EXECUTION:
                        case TASK_FINISHED:
                                // our tasks are placed only in first queue (see BaseLocalPlugin.placeTasksInQueues() method)
                                Queue<? extends TaskInterface<?>> q = queues.get(0);
                                // check all tasks in queue
                                for(int i = 0; i < q.size(); i++){
                                        TaskInterface<?> task = q.get(i);
                                        // if status of the tasks in READY
                                        if(task.getStatus() == Gridlet.READY){
                                                // then try to execute this task. Add it the execute list.
                                                if(execute.add(task)){
                                                        // if task started successfully, then remove it from the queue.
                                                        q.remove(i);
                                                        i--; // index trick to get the right position in the queue after task removal.
                                                }
                                                else{
                                                        break;
                                                }
                                        }
                                }
                                break;
                }
                
        }

        public String getPluginName() {
                return getClass().getName();
        }

        public void initPlugin(Properties properties) {
                // no extra initialization is expected.
        }
        
}