software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension 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;
import software.amazon.awssdk.annotations.SdkPublicApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.enhanced.dynamodb.extensions.ReadModification;
import software.amazon.awssdk.enhanced.dynamodb.extensions.WriteModification;
/**
* Interface for extending the DynamoDb Enhanced client. Two hooks are provided, one that is called just before a record
* is written to the database, and one called just after a record is read from the database. This gives the extension the
* opportunity to act as an invisible layer between the application and the database and transform the data accordingly.
*
* Multiple extensions can be used with the enhanced client, but the order in which they are loaded is important. For
* instance one extension may overwrite the value of an attribute that another extension then includes in a checksum
* calculation.
*/
@SdkPublicApi
@ThreadSafe
public interface DynamoDbEnhancedClientExtension {
/**
* This hook is called just before an operation is going to write data to the database. The extension that
* implements this method can choose to transform the item itself, or add a condition to the write operation
* or both.
*
* @param context The {@link DynamoDbExtensionContext.BeforeWrite} context containing the state of the execution.
* @return A {@link WriteModification} object that can alter the behavior of the write operation.
*/
default WriteModification beforeWrite(DynamoDbExtensionContext.BeforeWrite context) {
return WriteModification.builder().build();
}
/**
* This hook is called just after an operation that has read data from the database. The extension that
* implements this method can choose to transform the item, and then it is the transformed item that will be
* mapped back to the application instead of the item that was actually read from the database.
*
* @param context The {@link DynamoDbExtensionContext.AfterRead} context containing the state of the execution.
* @return A {@link ReadModification} object that can alter the results of a read operation.
*/
default ReadModification afterRead(DynamoDbExtensionContext.AfterRead context) {
return ReadModification.builder().build();
}
}