import java.util.ArrayList;
import java.util.Iterator;
import java.util.Random;

public class LeitnerStudyMethod extends AbstractStudyMethod{


public LeitnerStudyMethod(){
    super();
}

private int randomPickBox(){
    int index = 0;
    double p = r.nextDouble();
    for(;index < BOXSIZE; ++index){
        if(p < boxes.get(index).getPivot()){
            break;
        }
    }
    return index;
}
public Flashcard randomPickCard(){
    int boxIndex = 0;
    int randomCardIndex;
    while(true){
        boxIndex = randomPickBox();
        if(boxes.get(boxIndex).getCards().size() > 0)
            break;
    }

    randomCardIndex = Math.abs(r.nextInt() % boxes.get(boxIndex).getCards().size());
    Flashcard flashcard = boxes.get(boxIndex).getCards().get(randomCardIndex);
    int randomSide = r.nextInt() % 2;
    if(randomSide == 0){
        flashcard.setSide(ESide.FRONT);
    }else{
        flashcard.setSide(ESide.BACK);
    }
    return flashcard;
}

import java.util.ArrayList;

public class DrillStudyMethod extends AbstractStudyMethod{
private ArrayList<Flashcard> pool;
public DrillStudyMethod(){
    super();
    pool = null;
}
@SuppressWarnings("unchecked")
public void setBoxNum(int boxNum){
    pool = (ArrayList<Flashcard>) this.getBoxes().get(boxNum).getCards().clone();
}

public ArrayList<Flashcard> getPool(){
    return pool;
}
public Flashcard randomPickCard(){
    if(pool.size() == 0)
        return null;
    int randomCardIndex = Math.abs(r.nextInt() % pool.size());
    Flashcard flashcard = pool.get(randomCardIndex);
    int randomSide = r.nextInt() % 2;
    if(randomSide == 0){
        flashcard.setSide(ESide.FRONT);
    }else{
        flashcard.setSide(ESide.BACK);
    }
    return flashcard;
}

public boolean dropCard(Flashcard flashcard){
    return pool.remove(flashcard);
}