All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.amazonaws.services.dynamodbv2.datamodeling.PaginatedScanList Maven / Gradle / Ivy

Go to download

The Amazon Web Services SDK for Java provides Java APIs for building software on AWS' cost-effective, scalable, and reliable infrastructure products. The AWS Java SDK allows developers to code against APIs for all of Amazon's infrastructure web services (Amazon S3, Amazon EC2, Amazon SQS, Amazon Relational Database Service, Amazon AutoScaling, etc).

The newest version!
/*
 * Copyright 2011-2014 Amazon Technologies, Inc.
 *
 * 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.util.List;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.PaginationLoadingStrategy;
import com.amazonaws.services.dynamodbv2.model.ScanRequest;
import com.amazonaws.services.dynamodbv2.model.ScanResult;

/**
 * Implementation of the List interface that represents the results from a scan
 * in AWS DynamoDB. Paginated results are loaded on demand when the user
 * executes an operation that requires them. Some operations, such as size(),
 * must fetch the entire list, but results are lazily fetched page by page when
 * possible.
 * 

* This is an unmodifiable list, so callers should not invoke any operations * that modify this list, otherwise they will throw an * UnsupportedOperationException. * * @param * The type of objects held in this list. * @see PaginatedList */ public class PaginatedScanList extends PaginatedList { /** The current scan request */ private final ScanRequest scanRequest; private final DynamoDBMapperConfig config; /** The current results for the last executed scan operation */ private ScanResult scanResult; public PaginatedScanList( DynamoDBMapper mapper, Class clazz, AmazonDynamoDB dynamo, ScanRequest scanRequest, ScanResult scanResult, PaginationLoadingStrategy paginationLoadingStrategy, DynamoDBMapperConfig config ) { super(mapper, clazz, dynamo, paginationLoadingStrategy); this.scanRequest = scanRequest; this.scanResult = scanResult; this.config = config; allResults.addAll(mapper.marshalIntoObjects( mapper.toParameters(scanResult.getItems(), clazz, config))); // If the results should be eagerly loaded at once if (paginationLoadingStrategy == PaginationLoadingStrategy.EAGER_LOADING) { loadAllResults(); } } @Override protected boolean atEndOfResults() { return scanResult.getLastEvaluatedKey() == null; } @Override protected synchronized List fetchNextPage() { scanRequest.setExclusiveStartKey(scanResult.getLastEvaluatedKey()); scanResult = dynamo.scan(DynamoDBMapper.applyUserAgent(scanRequest)); return mapper.marshalIntoObjects( mapper.toParameters(scanResult.getItems(), clazz, config)); } }





© 2015 - 2025 Weber Informatics LLC | Privacy Policy