software.amazon.awssdk.enhanced.dynamodb.extensions.AutoGeneratedUuidExtension Maven / Gradle / Ivy
/*
* Copyright 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.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. 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 software.amazon.awssdk.enhanced.dynamodb.extensions;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.function.Consumer;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.enhanced.dynamodb.AttributeValueType;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbExtensionContext;
import software.amazon.awssdk.enhanced.dynamodb.EnhancedType;
import software.amazon.awssdk.enhanced.dynamodb.mapper.StaticAttributeTag;
import software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableMetadata;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbUpdateBehavior;
import software.amazon.awssdk.services.dynamodb.model.AttributeValue;
import software.amazon.awssdk.utils.Validate;
/**
* This extension facilitates the automatic generation of a unique UUID (Universally Unique Identifier) for a specified attribute
* every time a new record is written to the database. The generated UUID is obtained using the
* {@link java.util.UUID#randomUUID()} method.
*
* This extension is not loaded by default when you instantiate a
* {@link software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient}. Therefore, you need to specify it in a custom
* extension when creating the enhanced client.
*
* Example to add AutoGeneratedUuidExtension along with default extensions is
* {@snippet :
* DynamoDbEnhancedClient.builder().extensions(Stream.concat(ExtensionResolver.defaultExtensions().stream(),
* Stream.of(AutoGeneratedUuidExtension.create())).collect(Collectors.toList())).build();
*}
*
*
* Example to just add AutoGeneratedUuidExtension without default extensions is
* {@snippet :
* DynamoDbEnhancedClient.builder().extensions(AutoGeneratedUuidExtension.create()).build();
*}
*
*
* To utilize the auto-generated UUID feature, first, create a field in your model that will store the UUID for the attribute.
* This class field must be of type {@link java.lang.String}, and you need to tag it as the autoGeneratedUuidAttribute. If you are
* using the {@link software.amazon.awssdk.enhanced.dynamodb.mapper.BeanTableSchema}, then you should use the
* {@link software.amazon.awssdk.enhanced.dynamodb.extensions.annotations.DynamoDbAutoGeneratedUuid} annotation. If you are using
* the {@link software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableSchema}, then you should use the
* {@link
* software.amazon.awssdk.enhanced.dynamodb.extensions.AutoGeneratedUuidExtension.AttributeTags#autoGeneratedUuidAttribute()}
* static attribute tag.
*
*
* Every time a new record is successfully put into the database, the specified attribute will be automatically populated with a
* unique UUID generated using {@link java.util.UUID#randomUUID()}. If the UUID needs to be created only for `putItem` and should
* not be generated for an `updateItem`, then
* {@link software.amazon.awssdk.enhanced.dynamodb.mapper.UpdateBehavior#WRITE_IF_NOT_EXISTS} must be along with
* {@link DynamoDbUpdateBehavior}
*
*
*/
@SdkPublicApi
@ThreadSafe
public final class AutoGeneratedUuidExtension implements DynamoDbEnhancedClientExtension {
private static final String CUSTOM_METADATA_KEY =
"software.amazon.awssdk.enhanced.dynamodb.extensions.AutoGeneratedUuidExtension:AutoGeneratedUuidAttribute";
private static final AutoGeneratedUuidAttribute AUTO_GENERATED_UUID_ATTRIBUTE = new AutoGeneratedUuidAttribute();
private AutoGeneratedUuidExtension() {
}
/**
* @return an Instance of {@link AutoGeneratedUuidExtension}
*/
public static AutoGeneratedUuidExtension create() {
return new AutoGeneratedUuidExtension();
}
/**
* Modifies the WriteModification UUID string with the attribute updated with the extension.
*
* @param context The {@link DynamoDbExtensionContext.BeforeWrite} context containing the state of the execution.
* @return WriteModification String updated with attribute updated with Extension.
*/
@Override
public WriteModification beforeWrite(DynamoDbExtensionContext.BeforeWrite context) {
Collection customMetadataObject = context.tableMetadata()
.customMetadataObject(CUSTOM_METADATA_KEY, Collection.class)
.orElse(null);
if (customMetadataObject == null) {
return WriteModification.builder().build();
}
Map itemToTransform = new HashMap<>(context.items());
customMetadataObject.forEach(key -> insertUuidInItemToTransform(itemToTransform, key));
return WriteModification.builder()
.transformedItem(Collections.unmodifiableMap(itemToTransform))
.build();
}
private void insertUuidInItemToTransform(Map itemToTransform,
String key) {
itemToTransform.put(key, AttributeValue.builder().s(UUID.randomUUID().toString()).build());
}
public static final class AttributeTags {
private AttributeTags() {
}
/**
* Tags which indicate that the given attribute is supported wih Auto Generated UUID Record Extension.
*
* @return Tag name for AutoGenerated UUID Records
*/
public static StaticAttributeTag autoGeneratedUuidAttribute() {
return AUTO_GENERATED_UUID_ATTRIBUTE;
}
}
private static class AutoGeneratedUuidAttribute implements StaticAttributeTag {
@Override
public void validateType(String attributeName, EnhancedType type,
AttributeValueType attributeValueType) {
Validate.notNull(type, "type is null");
Validate.notNull(type.rawClass(), "rawClass is null");
Validate.notNull(attributeValueType, "attributeValueType is null");
if (!type.rawClass().equals(String.class)) {
throw new IllegalArgumentException(String.format(
"Attribute '%s' of Class type %s is not a suitable Java Class type to be used as a Auto Generated "
+ "Uuid attribute. Only String Class type is supported.", attributeName, type.rawClass()));
}
}
@Override
public Consumer modifyMetadata(String attributeName,
AttributeValueType attributeValueType) {
return metadata -> metadata.addCustomMetadataObject(CUSTOM_METADATA_KEY, Collections.singleton(attributeName))
.markAttributeAsKey(attributeName, attributeValueType);
}
}
}