com.amazonaws.services.dynamodbv2.datamodeling

Enum DynamoDBMapperConfig.PaginationLoadingStrategy

java.lang.Object

java.lang.Enum<DynamoDBMapperConfig.PaginationLoadingStrategy>

com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.PaginationLoadingStrategy

All Implemented Interfaces:

Serializable, Comparable<DynamoDBMapperConfig.PaginationLoadingStrategy>

Enclosing class:

DynamoDBMapperConfig

public static enum DynamoDBMapperConfig.PaginationLoadingStrategy
extends Enum<DynamoDBMapperConfig.PaginationLoadingStrategy>

Enumeration of pagination loading strategy.

Enum Constant Summary

Enum Constants

Enum Constant and Description
EAGER_LOADING Paginated list will eagerly load all the paginated results from DynamoDB as soon as the list is initialized.
ITERATION_ONLY Only supports using iterator to read from the paginated list.
LAZY_LOADING Paginated list is lazily loaded when possible, and all loaded results are kept in the memory.

Method Summary

Modifier and Type	Method and Description
DynamoDBMapperConfig	config()
static DynamoDBMapperConfig.PaginationLoadingStrategy	valueOf(String name) Returns the enum constant of this type with the specified name.
static DynamoDBMapperConfig.PaginationLoadingStrategy[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

LAZY_LOADING

public static final DynamoDBMapperConfig.PaginationLoadingStrategy LAZY_LOADING

Paginated list is lazily loaded when possible, and all loaded results are kept in the memory. Data will only be fetched when accessed so this can be more performant than EAGER_LOADING when not all data is used. Calls to methods such as List.size() will cause all results to be fetched from the service.

By default, the mapper uses LAZY_LOADING.

ITERATION_ONLY

public static final DynamoDBMapperConfig.PaginationLoadingStrategy ITERATION_ONLY

Only supports using iterator to read from the paginated list. All other list operations will return UnsupportedOperationException immediately. During the iteration, the list will clear all the previous results before loading the next page, so that the list will keep at most one page of the loaded results in memory. This also means the list could only be iterated once.

Use this configuration to reduce the memory overhead when handling large DynamoDB items. This is the most performant option when you only need to iterate the results of a query.

EAGER_LOADING

public static final DynamoDBMapperConfig.PaginationLoadingStrategy EAGER_LOADING

Paginated list will eagerly load all the paginated results from DynamoDB as soon as the list is initialized. This may make several service calls when the list is created and is not recommended for large data sets. The benefit of using eager loading is that service call penalties are paid up front and you get predictable latencies when accessing the list afterwards since all contents are in memory.

Method Detail

values

public static DynamoDBMapperConfig.PaginationLoadingStrategy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DynamoDBMapperConfig.PaginationLoadingStrategy c : DynamoDBMapperConfig.PaginationLoadingStrategy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DynamoDBMapperConfig.PaginationLoadingStrategy valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

config

public final DynamoDBMapperConfig config()