content: /*
   * 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.cassandra.index.sai.disk.format;
  
  import java.util.Comparator;
  import java.util.SortedSet;
  import java.util.TreeSet;
  import java.util.stream.Collectors;
  
  import javax.annotation.Nullable;
  
  import com.google.common.base.Objects;
  
  import org.apache.cassandra.config.CassandraRelevantProperties;
  import org.apache.cassandra.index.sai.disk.v1.V1OnDiskFormat;
  import org.apache.cassandra.index.sai.utils.IndexIdentifier;
  import org.apache.cassandra.io.sstable.Component;
  import org.apache.cassandra.io.sstable.Descriptor;
  
  /**
   * Format version of indexing component, denoted as [major][minor]. Same forward-compatibility rules apply as to
   * {@link org.apache.cassandra.io.sstable.format.Version}.
   */
  public class Version implements Comparable<Version>
  {
      public static final String SAI_DESCRIPTOR = "SAI";
      public static final String SAI_SEPARATOR = "+";
  
      // Current version
      public static final Version AA = new Version("aa", V1OnDiskFormat.instance, (c, i) -> defaultFileNameFormat(c, i, "aa"));
  
      // These should be added in reverse order so that the latest version is used first. Version matching tests
      // are more likely to match the latest version, so we want to test that one first.
      public static final SortedSet<Version> ALL = new TreeSet<>(Comparator.reverseOrder()) {{
          add(AA);
      }};
  
      public static final Version EARLIEST = AA;
      // The latest version can be configured to be an earlier version to support partial upgrades that don't
      // write newer versions of the on-disk formats.
      public static final Version LATEST = CassandraRelevantProperties.SAI_LATEST_VERSION.convert(Version::parse);
  
      private final String version;
      private final OnDiskFormat onDiskFormat;
      private final FileNameFormatter fileNameFormatter;
  
      private Version(String version, OnDiskFormat onDiskFormat, FileNameFormatter fileNameFormatter)
      {
          this.version = version;
          this.onDiskFormat = onDiskFormat;
          this.fileNameFormatter = fileNameFormatter;
      }
  
      public static Version parse(String versionString)
      {
          for (Version version : ALL)
              if (version.version.equals(versionString))
                  return version;
          throw new IllegalArgumentException("The version string " + versionString + " does not represent a valid SAI version. " +
                                             "It should be one of " + ALL.stream().map(Version::toString).collect(Collectors.joining(", ")));
      }
  
      @Override
      public int compareTo(Version other)
      {
          return version.compareTo(other.version);
      }
  
      @Override
      public int hashCode()
      {
          return Objects.hashCode(version);
      }
  
      @Override
      public boolean equals(Object o)
      {
          if (this == o) return true;
          if (o == null || getClass() != o.getClass()) return false;
          Version other = (Version)o;
          return Objects.equal(version, other.version);
      }
  
      @Override
      public String toString()
      {
          return version;
      }
  
      public boolean onOrAfter(Version other)
      {
          return version.compareTo(other.version) >= 0;
      }
  
      public OnDiskFormat onDiskFormat()
      {
          return onDiskFormat;
      }
  
      public Component makePerSSTableComponent(IndexComponent indexComponent)
      {
          return indexComponent.type.createComponent(fileNameFormatter.format(indexComponent, null));
      }
  
      public Component makePerIndexComponent(IndexComponent indexComponent, IndexIdentifier indexIdentifier)
      {
          return indexComponent.type.createComponent(fileNameFormatter.format(indexComponent, indexIdentifier));
      }
  
      public FileNameFormatter fileNameFormatter()
      {
          return fileNameFormatter;
      }
  
      public interface FileNameFormatter
      {
          String format(IndexComponent indexComponent, IndexIdentifier indexIdentifier);
      }
  
      /**
       * SAI default filename formatter. This is the current SAI on-disk filename format
       * <p>
       * Format: {@code <sstable descriptor>-SAI+<version>(+<index name>)+<component name>.db}
       * Note: The index name is excluded for per-SSTable index files that are shared
       * across all the per-column indexes for the SSTable.
       */
      private static String defaultFileNameFormat(IndexComponent indexComponent,
                                                  @Nullable IndexIdentifier indexIdentifier,
                                                  String version)
      {
          StringBuilder stringBuilder = new StringBuilder();
  
          stringBuilder.append(SAI_DESCRIPTOR);
          stringBuilder.append(SAI_SEPARATOR).append(version);
          if (indexIdentifier != null)
              stringBuilder.append(SAI_SEPARATOR).append(indexIdentifier.indexName);
          stringBuilder.append(SAI_SEPARATOR).append(indexComponent.name);
          stringBuilder.append(Descriptor.EXTENSION);
  
          return stringBuilder.toString();
      }
  }
  