Count number of items with property

Question

I have list List where Custom is like

class Custom{
    public int id;
    public String name;
}

How to

Answer 1

You can use count() from Eclipse Collections.

MutableList customList = Lists.mutable.empty();
int count = customList.count(each -> "Tom".equals(each.getName()));

If you can't change customList from List:

List customList = new ArrayList<>();
int count = ListAdapter.adapt(customList).count(each -> "Tom".equals(each.getName()));

If you have a method which checks for a name you can also use countWith():

MutableList customList = Lists.mutable.empty();
int count = customList.countWith(Custom::isNamed, "Tom");

class Custom
{
    public int id;
    public String name;

    public boolean isNamed(String nameToCheck)
    {
        return nameToCheck.equals(this.name);
    }
}

Note: I am a contributor to Eclipse Collections.