/*
* Copyright 2011-2017 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;
/**
* Annotation to mark a property as using a custom auto-generator.
*
* <p>May be annotated on a user-defined annotation to pass additional
* properties to the {@link DynamoDBAutoGenerator}.</p>
*
* <pre class="brush: java">
* @DynamoDBHashKey
* @CustomGeneratedKey(prefix="test-") //<- user-defined annotation
* public String getKey()
* </pre>
*
* <p>Where,</p>
* <pre class="brush: java">
* @DynamoDBAutoGenerated(generator=CustomGeneratedKey.Generator.class)
* @Retention(RetentionPolicy.RUNTIME)
* @Target({ElementType.METHOD})
* public @interface CustomGeneratedKey {
* String prefix() default "";
*
* public static class Generator implements DynamoDBAutoGenerator<String> {
* private final String prefix;
* public Generator(final Class<String> targetType, final CustomGeneratedKey annotation) {
* this.prefix = annotation.prefix();
* }
* public Generator() { //<- required if annotating directly
* this.prefix = "";
* }
* @Override
* public DynamoDBAutoGenerateStrategy getGenerateStrategy() {
* return DynamoDBAutoGenerateStrategy.CREATE;
* }
* @Override
* public final String generate(final String currentValue) {
* return prefix + UUID.randomUUID.toString();
* }
* }
* }
* </pre>
*
* <p>Alternately, the property/field may be annotated directly (which requires
* the generator to provide a default constructor),</p>
* <pre class="brush: java">
* @DynamoDBAutoGenerated(generator=CustomGeneratedKey.Generator.class)
* public String getKey()
* </pre>
*
* <p>May be used as a meta-annotation.</p>
*/
@DynamoDB
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD, ElementType.ANNOTATION_TYPE})
public @interface DynamoDBAutoGenerated {
/**
* The auto-generator class for this property.
*/
@SuppressWarnings("rawtypes")
Class<? extends DynamoDBAutoGenerator> generator();
}