Package software.amazon.awssdk.enhanced.dynamodb.internal.operations

Interface PaginatedOperation<ItemT,RequestT,ResponseT>

Type Parameters:

ItemT - The modelled object that this table maps records to.

RequestT - The type of the request object for the DynamoDb call in the low level DynamoDbClient or DynamoDbAsyncClient.

ResponseT - The type of the response object for the DynamoDb call in the low level DynamoDbClient or DynamoDbAsyncClient.

All Known Subinterfaces:

PaginatedIndexOperation<ItemT,RequestT,ResponseT>, PaginatedTableOperation<ItemT,RequestT,ResponseT>

All Known Implementing Classes:

QueryOperation, ScanOperation

public interface PaginatedOperation<ItemT,RequestT,ResponseT>

Common interface for an operation that can be executed in a synchronous or non-blocking asynchronous fashion against a mapped database table and is expected to return a paginated list of results. These operations can be made against either the primary index of a table or a secondary index, although some implementations of this interface do not support secondary indices and will throw an exception when executed against one. Typically, each page of results that is served will automatically perform an additional service call to DynamoDb to retrieve the next set of results.

This interface is extended by PaginatedTableOperation and PaginatedIndexOperation which contain implementations of the behavior to actually execute the operation in the context of a table or secondary index and are used by DynamoDbTable or DynamoDbAsyncTable and DynamoDbIndex or DynamoDbAsyncIndex respectively. By sharing this common interface operations are able to re-use code regardless of whether they are executed in the context of a primary or secondary index or whether they are being executed in a synchronous or non-blocking asynchronous fashion.

Method Summary

Modifier and Type	Method	Description
Function<RequestT,SdkPublisher<ResponseT>>	asyncServiceCall(DynamoDbAsyncClient dynamoDbAsyncClient)	Provides a function for making the low level non-blocking asynchronous SDK call to DynamoDb.
default PageIterable<ItemT>	execute(TableSchema<ItemT> tableSchema, OperationContext context, DynamoDbEnhancedClientExtension extension, DynamoDbClient dynamoDbClient)	Default implementation of a complete synchronous execution of this operation against either the primary or a secondary index.
default PagePublisher<ItemT>	executeAsync(TableSchema<ItemT> tableSchema, OperationContext context, DynamoDbEnhancedClientExtension extension, DynamoDbAsyncClient dynamoDbAsyncClient)	Default implementation of a complete non-blocking asynchronous execution of this operation against either the primary or a secondary index.
RequestT	generateRequest(TableSchema<ItemT> tableSchema, OperationContext context, DynamoDbEnhancedClientExtension extension)	This method generates the request that needs to be sent to a low level DynamoDbClient.
Function<RequestT,SdkIterable<ResponseT>>	serviceCall(DynamoDbClient dynamoDbClient)	Provides a function for making the low level synchronous SDK call to DynamoDb.
Page<ItemT>	transformResponse(ResponseT response, TableSchema<ItemT> tableSchema, OperationContext context, DynamoDbEnhancedClientExtension dynamoDbEnhancedClientExtension)	Takes the response object returned by the actual DynamoDb call and maps it into a higher level abstracted result object.

Method Details

generateRequest

RequestT generateRequest(TableSchema<ItemT> tableSchema,
 OperationContext context,
 DynamoDbEnhancedClientExtension extension)

This method generates the request that needs to be sent to a low level DynamoDbClient.

Parameters:

tableSchema - A TableSchema that maps the table to a modelled object.

context - An object containing the context, or target, of the command execution.

extension - A DynamoDbEnhancedClientExtension that may modify the request of this operation. A null value here will result in no modifications.

Returns:

A request that can be used as an argument to a DynamoDbClient call to perform the operation.

serviceCall

Function<RequestT,SdkIterable<ResponseT>> serviceCall(DynamoDbClient dynamoDbClient)

Provides a function for making the low level synchronous SDK call to DynamoDb.

Parameters:

dynamoDbClient - A low level DynamoDbClient to make the call against.

Returns:

A function that calls a paginated DynamoDb operation with a provided request object and returns the response object.

asyncServiceCall

Function<RequestT,SdkPublisher<ResponseT>> asyncServiceCall(DynamoDbAsyncClient dynamoDbAsyncClient)

Provides a function for making the low level non-blocking asynchronous SDK call to DynamoDb.

Parameters:

dynamoDbAsyncClient - A low level DynamoDbAsyncClient to make the call against.

Returns:

A function that calls a paginated DynamoDb operation with a provided request object and returns the response object.

transformResponse

Page<ItemT> transformResponse(ResponseT response,
 TableSchema<ItemT> tableSchema,
 OperationContext context,
 DynamoDbEnhancedClientExtension dynamoDbEnhancedClientExtension)

Takes the response object returned by the actual DynamoDb call and maps it into a higher level abstracted result object.

Parameters:

response - The response object returned by the DynamoDb call for this operation.

tableSchema - A TableSchema that maps the table to a modelled object.

context - An object containing the context, or target, of the command execution.

dynamoDbEnhancedClientExtension - A DynamoDbEnhancedClientExtension that may modify the result of this operation. A null value here will result in no modifications.

Returns:

A high level result object as specified by the implementation of this operation.

execute

default PageIterable<ItemT> execute(TableSchema<ItemT> tableSchema,
 OperationContext context,
 DynamoDbEnhancedClientExtension extension,
 DynamoDbClient dynamoDbClient)

Default implementation of a complete synchronous execution of this operation against either the primary or a secondary index.

It performs three steps:

1. Call generateRequest(software.amazon.awssdk.enhanced.dynamodb.TableSchema<ItemT>, software.amazon.awssdk.enhanced.dynamodb.OperationContext, software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension) to get the request object.
2. Call asyncServiceCall(software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient) and call it using the request object generated in the previous step.
3. Wraps the SdkIterable that was returned by the previous step with a transformation that turns each object returned to a high level result.

Parameters:

tableSchema - A TableSchema that maps the table to a modelled object.

context - An object containing the context, or target, of the command execution.

extension - A DynamoDbEnhancedClientExtension that may modify the request or result of this operation. A null value here will result in no modifications.

dynamoDbClient - A DynamoDbClient to make the call against.

Returns:

A high level result object as specified by the implementation of this operation.

executeAsync

default PagePublisher<ItemT> executeAsync(TableSchema<ItemT> tableSchema,
 OperationContext context,
 DynamoDbEnhancedClientExtension extension,
 DynamoDbAsyncClient dynamoDbAsyncClient)

Default implementation of a complete non-blocking asynchronous execution of this operation against either the primary or a secondary index.

It performs three steps:

1. Call generateRequest(software.amazon.awssdk.enhanced.dynamodb.TableSchema<ItemT>, software.amazon.awssdk.enhanced.dynamodb.OperationContext, software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClientExtension) to get the request object.
2. Call asyncServiceCall(software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient) and call it using the request object generated in the previous step.
3. Wraps the SdkPublisher returned by the SDK in a new one that calls transformResponse() to convert the response objects published to a high level result.

Parameters:

tableSchema - A TableSchema that maps the table to a modelled object.

context - An object containing the context, or target, of the command execution.

extension - A DynamoDbEnhancedClientExtension that may modify the request or result of this operation. A null value here will result in no modifications.

dynamoDbAsyncClient - A DynamoDbAsyncClient to make the call against.

Returns:

An SdkPublisher that will publish pages of the high level result object as specified by the implementation of this operation.