+ private ShardIdentifier(String shardName, MemberName memberName, String type) {
+ this.shardName = Preconditions.checkNotNull(shardName, "shardName should not be null");
+ this.memberName = Preconditions.checkNotNull(memberName, "memberName should not be null");
+ this.type = Preconditions.checkNotNull(type, "type should not be null");