Homework.java

package ca.ubc.cpsc210.snippeting.examprep;

import java.util.ArrayList;
import java.util.List;
		
/**
 * A representation of a collection of tasks assigned to a student that have
 * not yet been completed.
 *
 * Tasks can be added to the collection with the addTask method.
 * This method receives two arguments:
 * (1) the name of the course to which this task belongs
 * (2) a measure of how many hours the task will take to complete
 *
 * Tasks are maintained in the order in which they are added. A student starts
 * working when the work method is called. Tasks will then be worked on in the
 * order in which they were added to the collection of tasks.
 * The work method returns a list of course names whose tasks will be worked
 * on in the new work session (no matter if they are only started or
 * also completed).
 *
 * An example:
 * Homework myHomework = new Homework();
 * myHomework.addTask("A", 1);
 * myHomework.addTask("B", 3);
 * myHomework.addTask("C", 1);
 *
 * myHomework.workOnTasks(2) will return [ "A", "B" ]
 * (the first task will be completed ("A") and the second task will be
 * begun ("B") but not completed)
 * myHomework.workOnTasks(1) will return [ "B" ]
 * (the second task will be worked on for an hour, but still not be
 * completed)
 * myHomework.workOnTasks(2) will return [ "B", "C" ]
 * (both the second and third tasks will be completed)
 * myHomework.workOnTasks(1) will return [ ] (the empty list)
 * (because there are no more tasks to be worked on)
 *
 * @author norm, modified by PC
 *
 */
public class Homework {

	private List<Task> tasks;
		
		
	// EFFECTS: constructs an empty collection of tasks
	public Homework() {
		this.tasks = new ArrayList<>();
	}
			
	// REQUIRES: neededHours > 0
	// MODIFIES: this
	// EFFECTS: adds a new task to the collection of tasks to be completed
	public void addTask(String className, int neededHours) {
		this.tasks.add(new Task(className, neededHours));
	}
			
	// REQUIRES: hours > 0
	// MODIFIES: this
	// EFFECTS: returns the list of the names of those courses for
	// which tasks will be worked on when hours work are performed;
	// the list returned could be empty (it is never null). Removes
	// tasks that have been completed from the list of tasks to
	// be worked on
	public List<String> workOnTasks(int hours) {
		List<String> tasksWorkedOn = new ArrayList<>();
		while (hours > 0 && this.tasks.size() > 0) {
			Task currentTask = this.tasks.get(0);
			tasksWorkedOn.add(currentTask.getCourseName());
			if (hours >= currentTask.getHours()) {
				hours -= currentTask.getHours();
				this.tasks.remove(currentTask);
			} else {
				currentTask.applyHours(hours);
				hours = 0;
			}
		}
		return tasksWorkedOn; // stub
	}
			
	// EFFECTS: returns number of hours needed to complete all assigned tasks
	public int hoursToGo() {
		int hours = 0;
		for (Task task : tasks) {
			hours += task.getHours();
		}
		return hours;
	}
			
	// EFFECTS: returns number of tasks remaining
	public int numTasksRemaining() {
		return this.tasks.size();
	}
}