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.io.sstable;
  
  import java.nio.ByteBuffer;
  import java.util.function.Supplier;
  import java.util.stream.Stream;
  
  import org.apache.cassandra.io.util.File;
  
  /**
   * Represents a unique identifier in the sstable descriptor filename.
   * This ensures each sstable file uniqueness for the certain table on a single node. However, new implementations
   * should ensure the uniqueness across the entire cluster. The legacy implementation which does not satisfy cluster-wide
   * uniqueness will be deprecated and eventually removed.
   * <p>
   * A new implementation must adhere to the following invariants:
   * - Must be locally sortable - that is, the comparison must reflect the comparison of generation times of identifiers
   * generated on the same node
   * - String representation must *not* include the {@link Descriptor#FILENAME_SEPARATOR} character, see {@link Descriptor#fromFileWithComponent(File)}
   * - must be case-insensitive because the sstables can be stored on case-insensitive file system
   * <p>
   */
  public interface SSTableId
  {
      /**
       * Creates a byte format of the identifier that can be parsed by
       * {@link Builder#fromBytes(ByteBuffer)}
       */
      ByteBuffer asBytes();
  
      /**
       * Creates a String format of the identifier that can be parsed by
       * {@link Builder#fromString(String)}
       * <p>
       * Must not contain any {@link Descriptor#FILENAME_SEPARATOR} character as it is used in the Descriptor
       * see {@link Descriptor#fromFileWithComponent(File)}
       */
      @Override
      String toString();
  
      /**
       * Builder that can create instances of certain implementation of {@link SSTableId}.
       */
      interface Builder<T extends SSTableId>
      {
          /**
           * Creates a new generator of identifiers. Each supplied value must be different to all the previously generated
           * values and different to all the provided existing identifiers.
           */
          Supplier<T> generator(Stream<SSTableId> existingIdentifiers);
  
          boolean isUniqueIdentifier(String str);
  
          boolean isUniqueIdentifier(ByteBuffer bytes);
  
          /**
           * Creates an identifier instance from its string representation
           *
           * @param str string representation as returned by {@link SSTableId#toString()}
           * @throws IllegalArgumentException when the provided string is not a valid string representation of the identifier
           */
          T fromString(String str) throws IllegalArgumentException;
  
          /**
           * Creates an identifier instance from its binary representation
           * <p>
           * The method expects the identifier is encoded in all remaining bytes of the buffer. The method does not move the
           * pointer of the buffer.
           *
           * @param bytes binary representation as returned by {@link #asBytes()}
           * @throws IllegalArgumentException when the provided bytes are not a valid binary representation of the identifier
           */
          T fromBytes(ByteBuffer bytes) throws IllegalArgumentException;
      }
  }
  