@Override
  public String toString() {
    StringBuilder sb = new StringBuilder("TableIdentifier(");
    boolean first = true;

    sb.append("catalog:");
    if (this.catalog == null) {
      sb.append("null");
    } else {
      sb.append(this.catalog);
    }
    first = false;
    if (!first) sb.append(", ");
    sb.append("database:");
    if (this.database == null) {
      sb.append("null");
    } else {
      sb.append(this.database);
    }
    first = false;
    if (!first) sb.append(", ");
    sb.append("tableName:");
    if (this.tableName == null) {
      sb.append("null");
    } else {
      sb.append(this.tableName);
    }
    first = false;
    sb.append(")");
    return sb.toString();
  }
Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/compaction/evaluator/amoro/TableIdentifier.java