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 accord.api;
  
  import javax.annotation.Nonnull;
  import javax.annotation.Nullable;
  
  import accord.primitives.Seekables;
  import accord.primitives.Timestamp;
  import accord.primitives.TxnId;
  
  /**
   * The computational/transformation part of a client query
   *
   * Query will be invoked at a coordinator before Update
   */
  public interface /**/Query
  {
      /**
       * Perform some transformation on the complete {@link Data} result of a {@link Read}
       * from some {@link DataStore}, to produce a {@link Result} to return to the client.
       *
       * executeAt timestamp is provided so that the result of the transaction can be determined based
       * on configuration at that epoch. This will be deterministic even if the transaction is recovered.
       */
      Result compute(@Nonnull TxnId txnId, @Nonnull Timestamp executeAt, @Nonnull Seekables<?, ?> keys, @Nullable Data data, @Nullable Read read, @Nullable Update update);
  }
  