@Override
  public int compareTo(TableName tableName) {
    // For performance reasons, the ordering is not lexicographic.
    if (this == tableName) {
      return 0;
    }
    if (this.hashCode < tableName.hashCode()) {
      return -1;
    }
    if (this.hashCode > tableName.hashCode()) {
      return 1;
    }
    return this.nameAsString.compareTo(tableName.getNameAsString());
  }
Construct a TableName
@throws IllegalArgumentException if fullName equals old root or old meta. Some code depends on
                                 this.
hbase-common/src/main/java/org/apache/hadoop/hbase/TableName.java