如何将其转换为使用java流？

Question

I have this method that will return an integer array of all the values in a specific position of all the enum values. I'm wondering how I can convert this to a stream to make it shorter and more efficient.

So that method returns an integer array containing 12, 16, 19, 15 but I'm wondering how I can shorten it with a stream.

Thanks!

ITEM_1(12),
ITEM_3(16),
ITEM_4(19),
ITEM_5(15);

private final int ITEM_ID;

ENUM_NAME(int item_id) {
    this.ITEM_ID = item_id;
}

public int[] getIDs() {
    final ENUM_NAME[] enum_name = ENUM_NAME.values();
    final int[] item_ids = new int[enum_name.length];

    for (int i = 0; i < enum_name.length; i++) {
        item_ids[i] = enum_name[i].getItemID();
    }

    return item_ids;
}

Answer 1

You can shorten looping through values with something like this:

Arrays.stream(ENUM_NAME.values()).map(t -> t.ITEM_ID)

It will create Stream with ITEM_ID values (values will be of type Integer)

To return int array (int[]), like getIDs() method in your code, use:

Arrays.stream(ENUM_NAME.values()).mapToInt(t -> t.ITEM_ID).toArray()