Is It Possible to get Arraylist of product name from Arraylist of custom class without looping

Question

Suppose I have class:

class Product {
   int pId;
   String pName;
   int pPrice;
}

I have Arraylist<Product>, so can I get ArrayList<String> which contain product name only without loop.

Say with help of cursor or collection utils or any other thing in android.

How you are adding data of product in arraylist? Because if you are adding product in arraylist at that same time you will have product name which you need to add in another arraylist, i think that is the best way to do that. And if you are dealing with DB then you can directly query and get data. — Silvans Solanki, Mar 17 '16 at 10:05
give us some more code where do you add Products to the list. — Vucko, Mar 17 '16 at 10:08

score 1 · Answer 1 · edited May 23 '17 at 12:15

1

In Java 8 you can use stream and map function on the list of your products.

Assume you have:

List<Product> productList = new ArrayList<Product>();
productList.add(new Product(1, "test", 100));
productList.add(new Product(1, "test2", 100));

You can use this approach to map it to List<String>:

List<String> productNames = productList.parallelStream()
                              .map(Product::getPName)
                              .collect(toList());

Edit:

Is it possible to use Java 8 for Android development?

edited May 23 '17 at 12:15

Community

1
1

answered Mar 17 '16 at 10:17

mzy

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u could have commented @mzy – DJphy Mar 17 '16 at 10:20

score 0 · Answer 2 · answered Mar 17 '16 at 10:29

This way might be helpful:

class Product {
    int pId;
    String pName;
    int pPrice;
}

List<Product> products = new ArrayList<>();

// add products

List<String> names = new AbstractList<String>() {
    @Override
    public String get(int location) {
        return products.get(location).pName;
    }

    @Override
    public int size() {
        return products.size();
    }
}

Is It Possible to get Arraylist of product name from Arraylist of custom class without looping

2 Answers2