core/src/main/java/org/apache/iceberg/MetadataColumns.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iceberg;

import java.util.Map;
import java.util.Set;
import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap;
import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet;
import org.apache.iceberg.types.Types;
import org.apache.iceberg.types.Types.NestedField;

public class MetadataColumns {

  private MetadataColumns() {
  }

  // IDs Integer.MAX_VALUE - (1-100) are used for metadata columns
  public static final NestedField FILE_PATH = NestedField.required(
      Integer.MAX_VALUE - 1, "_file", Types.StringType.get(), "Path of the file in which a row is stored");
  public static final NestedField ROW_POSITION = NestedField.required(
      Integer.MAX_VALUE - 2, "_pos", Types.LongType.get(), "Ordinal position of a row in the source data file");
  public static final NestedField IS_DELETED = NestedField.required(
      Integer.MAX_VALUE - 3, "_deleted", Types.BooleanType.get(), "Whether the row has been deleted");

  // IDs Integer.MAX_VALUE - (101-200) are used for reserved columns
  public static final NestedField DELETE_FILE_PATH = NestedField.required(
      Integer.MAX_VALUE - 101, "file_path", Types.StringType.get(), "Path of a file in which a deleted row is stored");
  public static final NestedField DELETE_FILE_POS = NestedField.required(
      Integer.MAX_VALUE - 102, "pos", Types.LongType.get(), "Ordinal position of a deleted row in the data file");
  public static final String DELETE_FILE_ROW_FIELD_NAME = "row";
  public static final int DELETE_FILE_ROW_FIELD_ID = Integer.MAX_VALUE - 103;
  public static final String DELETE_FILE_ROW_DOC = "Deleted row values";

  private static final Map<String, NestedField> META_COLUMNS = ImmutableMap.of(
      FILE_PATH.name(), FILE_PATH,
      ROW_POSITION.name(), ROW_POSITION,
      IS_DELETED.name(), IS_DELETED);

  private static final Set<Integer> META_IDS = META_COLUMNS.values().stream().map(NestedField::fieldId)
      .collect(ImmutableSet.toImmutableSet());

  public static Set<Integer> metadataFieldIds() {
    return META_IDS;
  }

  public static NestedField get(String name) {
    return META_COLUMNS.get(name);
  }

  public static boolean isMetadataColumn(String name) {
    return META_COLUMNS.containsKey(name);
  }

  public static boolean nonMetadataColumn(String name) {
    return !META_COLUMNS.containsKey(name);
  }
}