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 com.datastax.oss.driver.api.mapper.annotations;
  
  import java.lang.annotation.ElementType;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  
  /**
   * Annotates a DAO-producing method in a {@link Mapper} interface.
   *
   * <p>Example:
   *
   * <pre>
   * &#64;Mapper
   * public interface InventoryMapper {
   *   &#64;DaoFactory
   *   ProductDao productDao();
   * }
   * </pre>
   *
   * The return type of the method must be a {@link Dao}-annotated interface.
   *
   * <p>If the method takes no arguments, the DAO operates on the session's default keyspace (assuming
   * that one was set), and the entity's default table:
   *
   * <pre>
   * // Example 1: the session has a default keyspace
   * CqlSession session = CqlSession.builder().withKeyspace("test").build();
   * InventoryMapper inventoryMapper = new InventoryMapperBuilder(session).build();
   * ProductDao dao = inventoryMapper.productDao();
   * Product product = dao.selectById(1);
   * // =&gt; success (selects from test.product)
   *
   * // Example 2: the session has no default keyspace
   * CqlSession session = CqlSession.builder().build();
   * InventoryMapper inventoryMapper = new InventoryMapperBuilder(session).build();
   * ProductDao dao = inventoryMapper.productDao();
   * Product product = dao.selectById(1);
   * // =&gt; CQL error (No keyspace has been specified. USE a keyspace, or explicitly specify keyspace.tablename)
   * </pre>
   *
   * You can also have the method take the keyspace and table as arguments (annotated respectively
   * with {@link DaoKeyspace} and {@link DaoTable}):
   *
   * <pre>
   * &#64;Mapper
   * public interface InventoryMapper {
   *   &#64;DaoFactory
   *   ProductDao productDao(@DaoKeyspace String keyspace);
   *
   *   &#64;DaoFactory
   *   ProductDao productDao(@DaoKeyspace String keyspace, @DaoTable String table);
   * }
   * </pre>
   *
   * This allows you to reuse the same DAO interface to operate on different tables:
   *
   * <pre>
   * ProductDao dao1 = inventoryMapper.productDao("keyspace1");
   * Product product = dao1.selectById(1); // selects from keyspace1.product
   *
   * ProductDao dao2 = inventoryMapper.productDao("keyspace2");
   * Product product = dao2.selectById(1); // selects from keyspace2.product
   *
   * ProductDao dao3 = inventoryMapper.productDao("keyspace3", "table3");
   * Product product = dao3.selectById(1); // selects from keyspace3.table3
   * </pre>
   *
   * In all cases, DAO instances are initialized lazily and cached for future calls:
   *
   * <pre>
   * ProductDao dao1 = inventoryMapper.productDao("keyspace1", "product");
   * ProductDao dao2 = inventoryMapper.productDao("keyspace1", "product");
   * assert dao1 == dao2; // same arguments, same instance
   * </pre>
   *
   * Note that the cache is a simple map with no eviction mechanism.
   */
  @Target(ElementType.METHOD)
  @Retention(RetentionPolicy.RUNTIME)
  public @interface DaoFactory {}
  