Hashtable Java

Trampas

I am an online store where I am using a hashtable for the shopping basket.

My web page is JSP and I have Java Class file which is seperate from the web page.

Everytime I add something to my hashtable my hashtable is empty.

Can someone help me to keep the information in my hashtable without clearing it down.

I probably shouldn't have

Hashtable hashtable = new Hashtable();


JSP Page
Basket basket = new Basket();

basket.addEnteries(intID);


java class

public void addEnteries (int intItemID)
{
int intID;
intID = intItemID;
int hashSize = 0;

Hashtable hashtable = new Hashtable();

hashSize = hashtable.size();
hashSize = hashSize + 1;
String key = String.valueOf(hashSize) ;
String value = String.valueOf(intID);

if (!hashtable.containsKey(key))
{
hashtable.put(key, value);
}

}


If more information is required I will supply

Thanks for your help

Blowfish

The simple answer is that you are right about this line:

Hashtable hashtable = new Hashtable();

The longer answer is that that definitely isn't your only problem.

Just a quick question, each ID is unique isn't it? Wouldn't it be far easier then to use that as your key? The value could then be the number of that item required. One of the main features of a hash table is that you actually have no need to know its size at all, so that can go.

Your addEntries method would be something like this:

public void addEntry(int itemID,  int numItems)
{  
    if(!hashTable.containsKey(itemID))
    {
        hashtable.put(itemID, numItems);
    }
}

[edit] You may also want to add an else statement, to inform your user that a duplicate item exists.

Trampas

Thanks for the response and help

I was going to do that put a person will be allowed to add the same item twice so that why I was heading down the size line.

I still need to declare the hashTable in the code don't I??

Torak

You need to do two things:

1. Create the basket as a session scope variable instead of every time on the page..

<jsp:useBean id="basket" scope="session" class="Basket" />

If you don't you will have the same problem. You will need to research this further to get it to work. The sun site is a good place to start.

2. Change the Hashtable to be a field in the class.

EOA_Mushy

Blowfish wrote:

Your addEntries method would be something like this:

public void addEntry(int itemID,  int numItems)
{  
    if(!hashTable.containsKey(itemID))
    {
        hashtable.put(itemID, numItems);
    }
    else{
        int x = hashtable.get(itemID);
        x += new amount of item
        hashtable.put(itemID,x);
   }
}

g