@Override
    public String getName() { return "WEAKAND"; }
Make a WeakAnd item with no children. You can mention a common index or you can mention it on each child.

@param index the index to search
@param n the target for minimum number of hits to produce;
       a backend will not suppress any hits in the operator
       until N hits have been produced.
container-search/src/main/java/com/yahoo/prelude/query/WeakAndItem.java