LowLevelBatchWrite.java

/*
* Copyright 2014-2015 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 com.amazonaws.codesamples.lowlevel;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.BatchWriteItemRequest;
import com.amazonaws.services.dynamodbv2.model.BatchWriteItemResult;
import com.amazonaws.services.dynamodbv2.model.ConsumedCapacity;
import com.amazonaws.services.dynamodbv2.model.DeleteRequest;
import com.amazonaws.services.dynamodbv2.model.PutRequest;
import com.amazonaws.services.dynamodbv2.model.ReturnConsumedCapacity;
import com.amazonaws.services.dynamodbv2.model.WriteRequest;

public class LowLevelBatchWrite {
    
    static AmazonDynamoDBClient client = new AmazonDynamoDBClient(new ProfileCredentialsProvider());
    static String table1Name = "Forum";
    static String table2Name = "Thread";
    
    public static void main(String[] args) throws IOException {

        writeMultipleItemsBatchWrite();  

    }

    
    private static void writeMultipleItemsBatchWrite() {
        try {                    
            
           // Create a map for the requests in the batch
           Map<String, List<WriteRequest>> requestItems = new HashMap<String, List<WriteRequest>>();
            
           // Create a PutRequest for a new Forum item
           Map<String, AttributeValue> forumItem = new HashMap<String, AttributeValue>();
           forumItem.put("Name", new AttributeValue().withS("Amazon RDS"));
           forumItem.put("Threads", new AttributeValue().withN("0"));
        
           List<WriteRequest> forumList = new ArrayList<WriteRequest>();
           forumList.add(new WriteRequest().withPutRequest(new PutRequest().withItem(forumItem)));
           requestItems.put(table1Name, forumList);
           
           // Create a PutRequest for a new Thread item
           Map<String, AttributeValue> threadItem = new HashMap<String, AttributeValue>();
           threadItem.put("ForumName", new AttributeValue().withS("Amazon RDS"));
           threadItem.put("Subject", new AttributeValue().withS("Amazon RDS Thread 1"));
           threadItem.put("Message", new AttributeValue().withS("ElasticCache Thread 1 message"));
           threadItem.put("KeywordTags", new AttributeValue().withSS(Arrays.asList("cache", "in-memory")));
        
           List<WriteRequest> threadList = new ArrayList<WriteRequest>();
           threadList.add(new WriteRequest().withPutRequest(new PutRequest().withItem(threadItem)));
           
           // Create a DeleteRequest for a Thread item
           Map<String, AttributeValue> threadDeleteKey = new HashMap<String, AttributeValue>(); 
           threadDeleteKey.put("ForumName", new AttributeValue().withS("Amazon S3"));
           threadDeleteKey.put("Subject", new AttributeValue().withS("S3 Thread 100"));
           
           threadList.add(new WriteRequest().withDeleteRequest(new DeleteRequest().withKey(threadDeleteKey)));
           requestItems.put(table2Name, threadList);
           
           BatchWriteItemResult result;
           BatchWriteItemRequest batchWriteItemRequest = new BatchWriteItemRequest()
               .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);
           
           do {
               System.out.println("Making the request.");
                               
               batchWriteItemRequest.withRequestItems(requestItems);
               result = client.batchWriteItem(batchWriteItemRequest);
               
               // Print consumed capacity units
               for(ConsumedCapacity consumedCapacity : result.getConsumedCapacity()) {
                    String tableName = consumedCapacity.getTableName();
                    Double consumedCapacityUnits = consumedCapacity.getCapacityUnits();
                    System.out.println("Consumed capacity units for table " + tableName + ": " + consumedCapacityUnits);
               }
               
               // Check for unprocessed keys which could happen if you exceed provisioned throughput
               System.out.println("Unprocessed Put and Delete requests: \n" + result.getUnprocessedItems());
               requestItems = result.getUnprocessedItems();
           } while (result.getUnprocessedItems().size() > 0);
                        
        }  catch (AmazonServiceException ase) {
            System.err.println("Failed to retrieve items: ");
            ase.printStackTrace(System.err);
        }  

    }

}