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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.nosql.appender;
    18
    19  import java.io.Closeable;
    20
    21  /**
    22   * Represents a connection to the NoSQL database. Serves as a factory for new (empty) objects and an endpoint for
    23   * inserted objects.
    24   *
    25   * @param <T> Specifies which implementation of {@link NoSqlObject} this connection provides.
    26   * @param <W> Specifies which type of database object is wrapped by the {@link NoSqlObject} implementation provided.
    27   */
    28  public interface NoSqlConnection<W, T extends NoSqlObject<W>> extends Closeable {
    29      /**
    30       * Instantiates and returns a {@link NoSqlObject} instance whose properties can be configured before ultimate
    31       * insertion via {@link #insertObject(NoSqlObject)}.
    32       *
    33       * @return a new object.
    34       * @see NoSqlObject
    35       */
    36      T createObject();
    37
    38      /**
    39       * Creates an array of the specified length typed to match the {@link NoSqlObject} implementation appropriate for
    40       * this provider.
    41       *
    42       * @param length the length of the array to create.
    43       * @return a new array.
    44       * @see NoSqlObject
    45       */
    46      T[] createList(int length);
    47
    48      /**
    49       * Inserts the given object into the underlying NoSQL database.
    50       *
    51       * @param object The object to insert.
    52       */
    53      void insertObject(NoSqlObject<W> object);
    54
    55      /**
    56       * Closes the underlying connection. This method call should be idempotent. Only the first call should have any
    57       * effect; all further calls should be ignored. It's possible the underlying connection is stateless (such as an
    58       * HTTP web service), in which case this method would be a no-op. This method should also commit any open
    59       * transactions, if applicable and if not already committed.
    60       * <p>
    61       * If this connection is part of a connection pool, executing this method should commit the transaction and return
    62       * the connection to the pool, but it should not actually close the underlying connection.
    63       * </p>
    64       */
    65      @Override
    66      void close();
    67
    68      /**
    69       * Indicates whether the underlying connection is closed. If the underlying connection is stateless (such as an
    70       * HTTP web service), this method would likely always return true. Essentially, this method should only return
    71       * {@code true} if a call to {@link #insertObject(NoSqlObject)} <b>will</b> fail due to the state of this object.
    72       *
    73       * @return {@code true} if this object is considered closed.
    74       */
    75      boolean isClosed();
    76  }