@Override
    public int hashCode() {
        int result = type.hashCode();
        result = 31 * result + (spanNode != null ? spanNode.hashCode() : 0);
        result = 31 * result + (value != null ? value.toString().hashCode() : 0);
        return result;
    }
Returns true if this Annotation has a value.

@return true if this Annotation has a value, false otherwise.
document/src/main/java/com/yahoo/document/annotation/Annotation.java