// extract from inventory
public int checkInventory(String sku, String color, String size, int quantity) {
InventoryPK pk = new InventoryPK(sku, color, size);
Inventory inventory = em.find(Inventory.class, pk, LockModeType.OPTIMISTIC);
int amount = inventory.getInventory();
if (amount > 0) {
if (amount >= quantity) {
amount = amount - quantity;
inventory.setInventory(amount);
try {
em.merge(inventory);
} catch (OptimisticLockException e) {
return -9999;
}
return quantity;
} else {
inventory.setInventory(0);
try {
em.merge(inventory);
} catch (OptimisticLockException e) {
return -9999;
}
return amount;
}
} else {
return amount;
}
}
// restore inventory when a product was removed from shopping cart
public int refreshInventory(String sku, String color, String size, int quantity) {
InventoryPK pk = new InventoryPK(sku, color, size);
Inventory inventory = em.find(Inventory.class, pk, LockModeType.OPTIMISTIC);
int amount = inventory.getInventory();
amount = amount + quantity;
inventory.setInventory(amount);
try {
em.merge(inventory);
} catch (OptimisticLockException e) {
return -9999;
}
return quantity;
}