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 the field or getter of an {@link Entity} property, to indicate that it's part of the
   * partition key.
   *
   * <p>Example:
   *
   * <pre>
   * &#64;PartitionKey private UUID id;
   * </pre>
   *
   * This information is used by the mapper processor to generate default queries (for example a basic
   * {@link Select}). Note that an entity is not required to have a partition key, for example if it
   * only gets mapped as a UDT.
   *
   * <p>If the partition key is composite, you must specify {@link #value()} to indicate the position
   * of each property:
   *
   * <pre>
   * &#64;PartitionKey(1) private int pk1;
   * &#64;PartitionKey(2) private int pk2;
   * </pre>
   *
   * If you don't specify positions, or if there are duplicates, the mapper processor will issue a
   * compile-time error.
   *
   * <p>This annotation is mutually exclusive with {@link ClusteringColumn}.
   */
  @Target({ElementType.FIELD, ElementType.METHOD})
  @Retention(RetentionPolicy.RUNTIME)
  public @interface PartitionKey {
  
    /**
     * The position of the property in the partition key.
     *
     * <p>This is only required if the partition key is composite. Positions are not strictly required
     * to be consecutive or start at a given index, but for clarity it is recommended to use
     * consecutive integers.
     */
    int value() default 0;
  }
  