@Override
    public String toString() {
        return type.getName() + " annotation" +
               ((value == null) ? " (no value)" : " (with value)") +
               ((spanNode == null) ? " (no span)" : (" with span " + spanNode));
    }
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