com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute Maven / Gradle / Ivy

/*
 * Copyright 2011-2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed 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://aws.amazon.com/apache2.0
 *
 * This file 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.amazonaws.services.dynamodbv2.datamodeling;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * Interface for marking a class property as an attribute in a DynamoDB table.
 * Applied to the getter method or the class field for a modeled property. If
 * the annotation is applied directly to the class field, the corresponding
 * getter and setter must be declared in the same class.
 * 
 * This annotation is optional when the name of the DynamoDB attribute matches
 * the name of the property declared in the class. When they differ, use this
 * annotation with the attributeName() parameter to specify which DynamoDB
 * attribute this property corresponds to. Furthermore, the
 * {@link DynamoDBMapper} class assumes Java naming conventions, and will
 * lower-case the first character of a getter method's property name to
 * determine the name of the property. E.g., a method getValue() will map to the
 * DynamoDB attribute "value". Similarly, a method isValid() maps to the
 * DynamoDB attribute "valid".
 * 
 * Getter methods not marked with this annotation are assumed to be modeled
 * properties, unless marked with {@link DynamoDBIgnore}.
 */
@DynamoDB
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD})
public @interface DynamoDBAttribute {

    /**
     * Optional parameter when the name of the attribute as stored in DynamoDB
     * should differ from the name used by the getter / setter.
     */
    String attributeName() default "";

    /**
     * Optional parameter when using {@link DynamoDBFlattened}; identifies
     * the field/property name on the target class to map as the attribute.
     * @see com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBFlattened
     */
    String mappedBy() default "";
}