public void setId(URI id) {
        if (this.id != null) throw new IllegalStateException("Attempt to change id of " + this + " to " + id);
        assignId(id);
    }
Initializes the id of this hit.

@throws NullPointerException if the uri is null
@throws IllegalStateException if the uri of this hit is already set
container-search/src/main/java/com/yahoo/search/result/Hit.java