Exam 2 Sample Questions from Spring 2012

Part III: Coding an Instantiable Class

public class ShippingContainer {

    private static long qty; // number of containers created
    private final long ID;
    private double emptyWeight;
    private double loadWeight;
    private double maxLoadWeight;
    
    public ShippingContainer( double maxLoad, double emptyWeight ) {
        this.maxLoadWeight = maxLoad;
        this.emptyWeight = emptyWeight;
        ID = qty;
        qty++;
        loadWeight = 0;
    }
        
    public static long getQuantity() { return qty; }
    
    public long getID() { return ID; }
    
    public double getWeight() { return emptyWeight + loadWeight; }
    
    public boolean load( double w ) {
        if ( loadWeight + w <= maxLoadWeight ) {
            loadWeight += w;
            return true;
        }
        return false;
    }
    
    public boolean isEmpty() { return loadWeight <= 0; }
    
    public boolean isFull() { return loadWeight >= maxLoadWeight; }
    
    public boolean unload( double w ) {
        if ( loadWeight - w >= 0 ) {
            loadWeight -= w;
            return true;
        }
        return false;
    }
    
    private static String gradeEgg( int w, char c ) {
        String grade = "Commerical"; // default if no match
        if ( c == 'w' ) {
            if ( w >= 30 ) 
                grade = "Jumbo";
            else if ( w >= 27 )
                grade = "Extra Large";
            else if ( w >= 24 )
                grade = "Large";
        }
        return grade;
    }
}