    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements. See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache license, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License. You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the license for the specific language governing permissions and
    015     * limitations under the license.
    016     */
    017    package org.apache.logging.log4j.nosql.appender;
    018
    019    import java.io.Closeable;
    020
    021    /**
    022     * Represents a connection to the NoSQL database. Serves as a factory for new (empty) objects and an endpoint for
    023     * inserted objects.
    024     *
    025     * @param <T> Specifies which implementation of {@link NoSqlObject} this connection provides.
    026     * @param <W> Specifies which type of database object is wrapped by the {@link NoSqlObject} implementation provided.
    027     */
    028    public interface NoSqlConnection<W, T extends NoSqlObject<W>> extends Closeable {
    029        /**
    030         * Instantiates and returns a {@link NoSqlObject} instance whose properties can be configured before ultimate
    031         * insertion via {@link #insertObject(NoSqlObject)}.
    032         *
    033         * @return a new object.
    034         * @see NoSqlObject
    035         */
    036        T createObject();
    037
    038        /**
    039         * Creates an array of the specified length typed to match the {@link NoSqlObject} implementation appropriate for
    040         * this provider.
    041         *
    042         * @param length the length of the array to create.
    043         * @return a new array.
    044         * @see NoSqlObject
    045         */
    046        T[] createList(int length);
    047
    048        /**
    049         * Inserts the given object into the underlying NoSQL database.
    050         *
    051         * @param object The object to insert.
    052         */
    053        void insertObject(NoSqlObject<W> object);
    054
    055        /**
    056         * Closes the underlying connection. This method call should be idempotent. Only the first call should have any
    057         * effect; all further calls should be ignored. It's possible the underlying connection is stateless (such as an
    058         * HTTP web service), in which case this method would be a no-op. This method should also commit any open
    059         * transactions, if applicable and if not already committed.
    060         * <p>
    061         * If this connection is part of a connection pool, executing this method should commit the transaction and return
    062         * the connection to the pool, but it should not actually close the underlying connection.
    063         * </p>
    064         */
    065        @Override
    066        void close();
    067
    068        /**
    069         * Indicates whether the underlying connection is closed. If the underlying connection is stateless (such as an
    070         * HTTP web service), this method would likely always return true. Essentially, this method should only return
    071         * {@code true} if a call to {@link #insertObject(NoSqlObject)} <b>will</b> fail due to the state of this object.
    072         *
    073         * @return {@code true} if this object is considered closed.
    074         */
    075        boolean isClosed();
    076    }