Items.add(item);

}

/**

* Formats shopping price.

*

* @return string as lines, separated with \n,

* first line: # Item Price Quan. Discount Total

* second line: ---------------------------------------------------------

* next lines: NN Title $PP.PP Q DD% $TT.TT

* 1 Some title $.30 2 - $.60

* 2 Some very long ti... $100.00 1 50% $50.00

*...

* 31 Item 42 $999.00 1000 - $999000.00

* end line: ---------------------------------------------------------

* last line: 31 $999050.60

*

* Item title is trimmed to 20 chars adding '...'

*

* if no items in cart returns " No items." string.

*/

Public String toString()

{

StringBuffer sb = new StringBuffer();

if (items.size() == 0)

return " No items.";

double total = 0.00;

sb.append(" # Item Price Quan. Discount Total\n");

sb.append(" ---------------------------------------------------------\n");

for (int i = 0; i < items.size(); i++) {

Item item = (Item) items.get(i);

int discount = calculateDiscount(item);

double itemTotal = item.price * item.quantity * (100.00 - discount) / 100.00;

appendPaddedRight(sb, String.valueOf(i + 1), 2);

sb.append(" ");

AppendPaddedLeft(sb, item.title, 20);

sb.append(" ");

AppendPaddedRight(sb, MONEY.format(item.price), 7);

sb.append(" ");

AppendPaddedRight(sb, String.valueOf(item.quantity), 4);

sb.append(" ");

if (discount == 0)

sb.append(" -");

else {

AppendPaddedRight(sb, String.valueOf(discount), 7);

sb.append(" %");

}

sb.append(" ");

AppendPaddedRight(sb, MONEY.format(itemTotal), 10);

sb.append(" \n");

total += itemTotal;

}

sb.append(" ---------------------------------------------------------\n");

AppendPaddedRight(sb, String.valueOf(items.size()), 2);

sb.append(" ");

AppendPaddedRight(sb, MONEY.format(total), 10);

Return sb.toString();

}

// --- private section -----------------------------------------------------

Private static final NumberFormat MONEY;

static {

DecimalFormatSymbols symbols = new DecimalFormatSymbols();

symbols.setDecimalSeparator('.');

MONEY = new DecimalFormat(" $#.00", symbols);

}

/**

* Adds to string buffer given string, padded with spaces.

* @return " str".length() == width

*/

Private static void appendPaddedRight(StringBuffer sb, String str, int width)

{

for (int i = str.length(); i < width; i++)

sb.append(" ");

Sb.append(str);

}

/**

* Adds string to buffer, wills spaces to width.

* If string is longer than width it is trimmed and ends with '...'

*/

Private static void appendPaddedLeft(StringBuffer sb, String str, int width)

{

if (str.length() > width) {

Sb.append(str.substring(0, width-3));

sb.append("...");

}

else {

Sb.append(str);

for (int i = str.length(); i < width; i++)

sb.append(" ");

}

}

/**

* Calculates item's discount.

* For Item.Type.REGULAR discount is 0%;

* For Item.Type.SECOND discount is 50% if quantity > 1

* For Item.Type.DISCOUNT discount is 10% + 10% for each full 10 items, but not more than 50%

* total

* For Item.Type.SALE discount is 90%

* For each full 100 items item gets additional 10%, but not more than 80% total

*/

Private static int calculateDiscount(Item item)

{

int discount = 0;

switch (item.type) {

case Item.Type.SECOND:

if (item.quantity > 1)

discount = 50;

Break;

case Item.Type.DISCOUNT:

discount = 10 + item.quantity / 10 * 10;

if (discount > 50)

discount = 50;

Break;

case Item.Type.SALE:

discount = 90;

}

discount += item.quantity / 100 * 10;

if (discount > 80)

discount = 80;