CODEWITHSUNDEEP
javalistobject
Andreas
Andreas

Reputation: 189

Get the Objects out of a list Java

Im doing a little text adventure. Im current working on a inventory. I tried to do my inventory with a list: ArrayList<Object> inventar = new ArrayList<Object>(); I initialize Objects as Items:

Item holzschwert = new Item("Holzschwert", 1, 5);
                inv.addToInventar(holzschwert);

Here's my add Method:

    public void addToInventar(Object ...item){
    inventar.add(item);
}

But everytime i want to print out my inventory (here's my toString() function) i still get the Hash code:

@Override
public String toString() {
    return "Inventar [ Inventar = " + inventar + " ]";
}

and my print method

Object test = inv.getInventar();
                String ausgabe = inv.toString();
                System.out.println(ausgabe);

and the console log:

Inventar [ Inventar = [[Ljava.lang.Object;@281c35ec] ]

Thank you for your help :)

Upvotes: 1

Views: 135

Answers (4)

Paul Boddington
Paul Boddington

Reputation: 37655

The mistake is

public void addToInventar(Object ...item){
    inventar.add(item);
}

Here item is an Object[], because you used varargs (...). What you are seeing is the result of calling toString on an array.

You want

public void addToInventar(Object item){
    inventar.add(item);
}

or possibly

public void addToInventar(Object... items){
    for (Object item : items)
        inventar.add(item);
}

EDIT

In addition to this answer, I should point out that you should probably not be using List<Object> anyway. List<Item> would be better as mistakes like this are more likely to be spotted by the compiler. The signature addToInventar(Object... items) should really be avoided like the plague, as it will accept literally any sequence of arguments of any length. All reference types are Objects and all primitives can be autoboxed.

Upvotes: 3

Troy
Troy

Reputation: 166

If you do not care about the exact format of the output, you can do something like this in your Item class:

@Override
public String toString() {
    return ToStringBuilder.reflectionToString(this);
}

ToStringBuilder is part of the Apache Commons Lang library. If you want it specifically formatted a certain way, then go with @Code Whisperer and write your own implementation.

Upvotes: 0

Code Whisperer
Code Whisperer

Reputation: 1041

@Override
public String toString() {
    StringBuffer stuff = new StringBuffer();
    for (Object item : inventar) {
        stuff.append(item.getName()); // you need a getter for the item name
        stuff.append(" ");
    }

    return stuff.toString();
}

Both your inventory and items are Objects. If you just print the objects and not the fields you will only get their memory address as output:

Ljava.lang.Object;@281c35ec

not the properties you've set up for them.

Upvotes: 0

Touchstone
Touchstone

Reputation: 5982

Override the Item class toString() method.

class Item{

   @override
   public String toString(){
       //Give your implementation
   }
}

Upvotes: 0

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