Sample Accumulo Counter

public class Counter extends WrappingIterator {
    Key top_key;
    Value top_value;

    @Override
    public boolean hasTop() {
        return top_key != null;
    }

    @Override
    public Key getTopKey() {
        return this.top_key;
    }

    @Override
    public Value getTopValue() {
        return this.top_value;
    }

    @Override
    public void next() {
        top_key = null;
        long count = 0L;
        while(this.source.hasTop()) {
            top_key = this.source.getTopKey();
            Value v = this.source.getTopValue();
            MyObject thing = deserialize(v.get());
            count += thing.count();
        this.source.next();
        }
        this.top_value = new Value(Long.toString(count).getBytes());
    }

    @Override
    public Counter deepCopy(IteratorEnvironment env) {
        Counter c = new Counter();
        c.setSource(getSource().deepCopy(env));
        return c;
    }
}