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.diag.store;
  
  import java.util.NavigableMap;
  
  import org.apache.cassandra.diag.DiagnosticEvent;
  
  /**
   * Enables storing and retrieving {@link DiagnosticEvent}s.
   * @param <T> type of key that is used to reference an event
   */
  public interface DiagnosticEventStore<T extends Comparable<T>>
  {
      /**
       * Initializes the store.
       */
      void load();
  
      /**
       * Stores provided event and returns the new associated store key for it.
       */
      void store(DiagnosticEvent event);
  
      /**
       * Returns a view on all events with a key greater than the provided value (inclusive) up to the specified
       * number of results. Events may be added or become unavailable over time. Keys must be unique, sortable and
       * monotonically incrementing. Returns an empty map in case no events could be found.
       */
      NavigableMap<T, DiagnosticEvent> scan(T key, int limit);
  
      /**
       * Returns the greatest event ID that can be used to fetch events via {@link #scan(Comparable, int)}.
       */
      T getLastEventId();
  }
  