private void setValue(FieldValue key, int weight) {
        this.value = key;
        this.weight = weight;
    }
<p>Value update representing an addition of a value (possibly with an associated weight)
to a multi-valued data type.</p>

@author <a href="mailto:einarmr@yahoo-inc.com">Einar M R Rosenvinge</a>
document/src/main/java/com/yahoo/document/update/AddValueUpdate.java