public String getState(String key) {
        if (key == null || key.length() == 0) {
            return null;
        }
        int pos = key.lastIndexOf("/");
        if (pos > -1) {
            NodeState parent = getChild(key.substring(0, pos), false);
            return parent != null ? parent.getState(key.substring(pos + 1)) : null;
        }
        return state.get(key);
    }
Retrieves some arbitrary state information for a given key. The key can be a location string, in which case the
necessary intermediate nodes are traversed. If the key is not found, this method returns null.

@param key The name of the state information to return.
@return The value of the state key.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/systemstate/rule/NodeState.java