[JAVA] java.lang.NullPointerException - Tilted Forum Project Discussion Community

BoltedDown · 01-25-2005, 05:16 PM

Ok guys, i've got some new code ready for ya...

Code:

java.lang.NullPointerException
	at restaurant1model.ProductCatalog.getSpecification(ProductCatalog.java:36)
	at restaurant1model.Register.enterItem(Register.java:54)
	at restaurant1view.Program1.main(Program1.java:54)

Code:

	public ProductSpecification getSpecification(String itemCode)
	{
		ProductSpecification item = null;
		boolean foundFlag = false;
		//System.out.println(itemCode);
		for (int i = 0; i < productSpecifications.length && !foundFlag; i++)				//for (int i = 0;!(i >= productSpecifications.length || foundFlag);	i++)		
		{
			if (itemCode.equals(productSpecifications[i].getItemId()))
			{
				item = productSpecifications[i];
				foundFlag = true;
			}
		}
		return item;
	}

Code:

	public boolean enterItem(String upc, int quantity)
	{
		boolean flag = false;
		if (sale == null || sale.isComplete())
		{
			sale = new Sale();
		}
		ProductSpecification productionSpecification;
		productionSpecification =
			(ProductSpecification) productCatalog.getSpecification(upc);
		if (productionSpecification != null)
		{
			flag = sale.makeLineItem(productionSpecification, quantity);
		}
		else
		{
			flag = false;
		}
		return flag;
	}

Code:

case 1 : // Event 1 - Enter Item
	{
		boolean doSaleAgain;
		do
		{
		int tableNumber = Program1.readInt("Enter Table Number");
		String itemCode = JOptionPane.showInputDialog("Enter Item Code", "X00");
		int quantity = Program1.readInt("Enter Quantity");
		register.enterItem(itemCode, quantity);
		doSaleAgain =
		readBoolean("Do you wish to enter another item?");
	}
	while (doSaleAgain);
	doAgain = true;
	break;
}

The bottom three snippets are all assosciated with their respective parts of the original error message (top). Let me know what you want to know and I will do my best to answer.

Thank you all very much!!

-BoltedDown

fckm · 01-25-2005, 06:37 PM

productSpecifications

in your first set of code. Is this a class variable? because it doesn't seem to exist anywhere else in your code.

Anomaly_ · 01-26-2005, 12:56 AM

I would guess you're calling getItemID() on an uninitialized (NULL) member of the productSpecifications array. I don't know the extent of your program, but a HashMap object might be better suited for your list of ProductSpecifications rather an an array, ArrayList, or whatever you're using to index it.

Also, as a tip, you can use the "break;" command in that for loop so you don't have to use a boolean flag. It simply breaks out of the inner most loop.

Rangsk · 01-27-2005, 07:53 PM

Out of curiosity, why not do this?

Code:

        public ProductSpecification getSpecification(String itemCode)
	{
		//System.out.println(itemCode);
		for (int i = 0; i < productSpecifications.length; i++)			
		{
			if (itemCode.equals(productSpecifications[i].getItemId()))
			{
				return productSpecifications[i];
			}
		}
		return null;
	}

As for your error, it sounds like ProductSpecifications is undefined when you run this function.

01-25-2005, 06:37 PM	#2 (permalink)
fckm Insane Location: Ithaca, New York	productSpecifications in your first set of code. Is this a class variable? because it doesn't seem to exist anywhere else in your code. __________________ And if you say to me tomorrow, oh what fun it all would be. Then what's to stop us, pretty baby. But What Is And What Should Never Be.

01-27-2005, 07:53 PM	#4 (permalink)
Rangsk Crazy Location: San Diego, CA	Out of curiosity, why not do this? Code: public ProductSpecification getSpecification(String itemCode) { //System.out.println(itemCode); for (int i = 0; i < productSpecifications.length; i++) { if (itemCode.equals(productSpecifications[i].getItemId())) { return productSpecifications[i]; } } return null; } As for your error, it sounds like ProductSpecifications is undefined when you run this function. __________________ "Don't believe everything you read on the internet. Except this. Well, including this, I suppose." -- Douglas Adams

01-26-2005, 12:56 AM	#3 (permalink)
Anomaly_ Insane	I would guess you're calling getItemID() on an uninitialized (NULL) member of the productSpecifications array. I don't know the extent of your program, but a HashMap object might be better suited for your list of ProductSpecifications rather an an array, ArrayList, or whatever you're using to index it. Also, as a tip, you can use the "break;" command in that for loop so you don't have to use a boolean flag. It simply breaks out of the inner most loop.