public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof ComparableObjectItem)) {
            return false;
        }
        ComparableObjectItem that = (ComparableObjectItem) obj;
        if (!this.x.equals(that.x)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.obj, that.obj)) {
            return false;
        }
        return true;