import java.util.ArrayList;
/**
 * A session is defined by the test subjects (students), the room,
 * the start time, and the duration.  Note that duration includes both
 * the active experiment time and the inter-session turn-around time.
 * @author Dr. Jody Paul
 * @version 14 March 2006
 */
public class Session {
    /** The default duration of a session, in minutes. */
    public static final int DEFAULT_DURATION = 10;

    /** The number of test subjects currently assigned to this session. */
    private int numberOfSubjects;
    /** The duration of this session. */
    private Time duration;
    /** The start time of this session. */
    private Time startTime;
    /** The room for this session. */
    private Room room;
    /** The test subjects in this session. */
    private java.util.ArrayList<Student> testSubjects;

    /**
     * Construct Session object with default duration.
     * Room and start time are set to <CODE>null</CODE>.
     * The list of test subjects is set to the empty list.
     */
    public Session() {
        numberOfSubjects = 0;
        duration = new Time(DEFAULT_DURATION);
        room = null;
        startTime = null;
        testSubjects = new ArrayList<Student>();
    }

    /**
     * Construct Session object with specified duration.
     * Room and start time are set to <CODE>null</CODE>.
     * The list of test subjects is set to the empty list.
     * @param theDuration the duration
     */
    public Session(Time theDuration) {
        numberOfSubjects = 0;
        duration = theDuration;
        room = null;
        startTime = null;
        testSubjects = new ArrayList<Student>();
    }

    /**
     * Construct Session object with specified duration, room and start time.
     * The list of test subjects is set to the empty list.
     * @param theDuration the duration
     * @param theRoom the room
     * @param theStartTime the start time
     */
    public Session(Time theDuration, Room theRoom, Time theStartTime) {
        numberOfSubjects = 0;
        duration = theDuration;
        room = theRoom;
        startTime = theStartTime;
        testSubjects = new ArrayList<Student>();
    }

    /**
     * Return the number of test subjects currently assigned to this session.
     * @return the number of subjects
     */
    public int getNumberOfSubjects() { return numberOfSubjects; }

    /**
     * Return the duration of this session.
     * @return the duration
     */
    public Time getDuration() { return duration; }

    /**
     * Return the start time of this session.
     * @return the start time
     */
    public Time getStartTime() { return startTime; }

    /**
     * Return the room of this session.
     * @return the room
     */
    public Room getRoom() { return room; }
    
    /**
     * Return the test subjects in this session.
     * @return the test subjects
     */
    public ArrayList<Student> getSubjects() { return testSubjects; }
    
    /**
     * Return a specific test subject.
     * @param which the index of the test subject
     * @return the test subject at index "which"
     */
    public Student getSubject(int which) {
        return testSubjects.get(which);
    }

    /**
     * Change the duration of this session.
     * @param newDuration the new duration (in minutes)
     */
    public void setDuration(Time newDuration) {
        duration = newDuration;
    }

    /**
     * Change the start time of this session.
     * @param newStartTime the new start time
     */
    public void setStartTime(Time newStartTime) {
        startTime = newStartTime;
    }

    /**
     * Change the room of this session.
     * @param newRoom the new room
     */
    public void setRoom(Room newRoom) {
        room = newRoom;
    }
    
    /**
     * Change the test subjects in this session.
     * @param newSubjects the new test subjects
     */
    public void setSubjects(ArrayList<Student> newSubjects) {
        testSubjects = newSubjects;
        numberOfSubjects = testSubjects.size();
    }
    
    /**
     * Add a test subject.
     * @param newSubject the new test subject
     */
    public void addSubject(Student newSubject) {
        testSubjects.add(newSubject);
        numberOfSubjects = testSubjects.size();
    }
}