public boolean hasValueUpdate(ValueUpdate.ValueUpdateClassID classID) {
        for (ValueUpdate vupd : valueUpdates) {
            if (vupd.getValueUpdateClassID() == classID) {
                return true;
            }
        }
        return false;
    }
Returns whether this field update contains (at least) one update of the given type

@param classID the classID of ValueUpdates to check for
@return true if there is at least one value update of the given type in this
document/src/main/java/com/yahoo/document/update/FieldUpdate.java