Java Printing Functions

Question

I need help writing the printing functions in this java application of another class.

The functions are with printAll I think is right and the other function is definite

Answer 1

Neither of these methods make any sense:

// An iterator of the SKU keys.
public Iterator<String> keys() {
    return new ;
}

// An iterator of the StockItem values.    
public Iterator<StockItem> values() {
    return null;
}

The first won't compile, and the second instantly causes NPEs when invoked. Now, what is a DictionaryADT? Does it implement Map? If so, it has a keySet and valueSet method, which you should use. Perhaps you can replace it with HashMap.

You do not need the toString calls in print and printAll, though I would prefer to reserve toString for debugging and write a separate method. However, why can't you use a foreach loop, assuming DictionaryADT implements Map:

public void printAll() {
    for (final StockItem item: dictionary.valueSet()) {
        System.out.println(item);
    }
}

Finally, use equals instead of == in your print method. You can look up why.

Answer 2

If DictionaryADT is a class with all the actual implementation, then you need to call

I believe you have Map inside DictionaryADT then, something like

public Collection<StockItem> values() {
    return dictionary.values(); 
}

to get the keys, Iterator is changed to Set

public Set<String> keys() {
    return dictionary.keySet(); // return Set, Please perform all the set opetations.
}

I believe this what you are looking for.

Thanks, Bennet.