Is there possibility of sum of ArrayList without looping

Question

Is there possibility of sum of ArrayList without looping?

PHP provides sum(array) which will give the sum of array.

The PHP code is

Answer 1

You can use apache commons-collections API.

class AggregateClosure implements org.apache.commons.collections.Closure {
        int total = 0;

        @Override
        public void execute(Object input) {
            if (input != null) {
                total += (Integer) input;
            }
        }

        public int getTotal() {
            return total;
        }
    }

Then use this closure as shown below:

public int aggregate(List aList) {
        AggregateClosure closure = new AggregateClosure();
        org.apache.commons.collections.CollectionUtils.forAllDo(aList, closure);
        return closure.getTotal();
}