com.amazonaws.services.dynamodbv2.document.ItemCollection Java Examples

private static void findRepliesUsingAFilterExpression(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);
        
        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id")
            .withFilterExpression("PostedBy = :v_postedby")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_postedby", "User B"));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesUsingAFilterExpression results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
     }
 

void scanTest(String tableName, DynamoDB client, int iterations) {
    long startTime, endTime;
    System.out.println("Scan test - all items in the table");
    Table table = client.getTable(tableName);

    for (int i = 0; i < iterations; i++) {
        startTime = System.nanoTime();
        ItemCollection<ScanOutcome> items = table.scan();
        try {

            Iterator<Item> iter = items.iterator();
            while (iter.hasNext()) {
                iter.next();
            }
        } catch (Exception e) {
            System.err.println("Unable to scan table:");
            e.printStackTrace();
        }
        endTime = System.nanoTime();
        printTime(startTime, endTime, iterations);
    }
}
 

private static void findRepliesInLast15DaysWithConfig(String tableName, String forumName, String threadSubject) {

        String replyId = forumName + "#" + threadSubject;
        long twoWeeksAgoMilli = (new Date()).getTime() - (15L * 24L * 60L * 60L * 1000L);
        Date twoWeeksAgo = new Date();
        twoWeeksAgo.setTime(twoWeeksAgoMilli);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String twoWeeksAgoStr = df.format(twoWeeksAgo);

        Table table = dynamoDB.getTable(tableName);

        QuerySpec querySpec = new QuerySpec().withKeyConditionExpression("Id = :v1 and ReplyDateTime > :v2")
            .withValueMap(new ValueMap().withString(":v1", replyId).withString(":v2", twoWeeksAgoStr))
            .withProjectionExpression("Message, ReplyDateTime, PostedBy");

        ItemCollection<QueryOutcome> items = table.query(querySpec);
        Iterator<Item> iterator = items.iterator();

        System.out.println("Query: printing results...");

        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
    }
 

private static void findProductsForPriceLessThanZero() {
    
    Table table = dynamoDB.getTable(tableName);
       
    Map<String, Object> expressionAttributeValues = new HashMap<String, Object>();
    expressionAttributeValues.put(":pr", 100);
    
    ItemCollection<ScanOutcome> items = table.scan(
        "Price < :pr", //FilterExpression
        "Id, Title, ProductCategory, Price", //ProjectionExpression
        null, //ExpressionAttributeNames - not used in this example 
        expressionAttributeValues);
    
    System.out.println("Scan of " + tableName + " for items with a price less than 100.");
    Iterator<Item> iterator = items.iterator();
    while (iterator.hasNext()) {
        System.out.println(iterator.next().toJSONPretty());
    }    
}
 

private static void findProductsForPriceLessThanOneHundred() {

        Table table = dynamoDB.getTable(tableName);

        Map<String, Object> expressionAttributeValues = new HashMap<String, Object>();
        expressionAttributeValues.put(":pr", 100);

        ItemCollection<ScanOutcome> items = table.scan("Price < :pr", // FilterExpression
            "Id, Title, ProductCategory, Price", // ProjectionExpression
            null, // ExpressionAttributeNames - not used in this example
            expressionAttributeValues);

        System.out.println("Scan of " + tableName + " for items with a price less than 100.");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
    }
 

private static void findRepliesForAThreadSpecifyOptionalLimit(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec().withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap().withString(":v_id", replyId)).withMaxPageSize(1);

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesForAThreadSpecifyOptionalLimit results:");

        // Process each page of results
        int pageNum = 0;
        for (Page<Item, QueryOutcome> page : items.pages()) {

            System.out.println("\nPage: " + ++pageNum);

            // Process each item on the current page
            Iterator<Item> item = page.iterator();
            while (item.hasNext()) {
                System.out.println(item.next().toJSONPretty());
            }
        }
    }
 

private static void findRepliesInLast15DaysWithConfig(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long twoWeeksAgoMilli = (new Date()).getTime() - (15L * 24L * 60L * 60L * 1000L);
        Date twoWeeksAgo = new Date();
        twoWeeksAgo.setTime(twoWeeksAgoMilli);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String twoWeeksAgoStr = df.format(twoWeeksAgo);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec().withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime <= :v_reply_dt_tm")
            .withValueMap(new ValueMap().withString(":v_id", replyId).withString(":v_reply_dt_tm", twoWeeksAgoStr));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesInLast15DaysWithConfig results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }
 

private static void findRepliesPostedWithinTimePeriod(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long startDateMilli = (new Date()).getTime() - (15L * 24L * 60L * 60L * 1000L);
        long endDateMilli = (new Date()).getTime() - (5L * 24L * 60L * 60L * 1000L);
        java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String startDate = df.format(startDateMilli);
        String endDate = df.format(endDateMilli);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec().withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime between :v_start_dt and :v_end_dt")
            .withValueMap(new ValueMap().withString(":v_id", replyId).withString(":v_start_dt", startDate)
                .withString(":v_end_dt", endDate));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesPostedWithinTimePeriod results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
    }
 

private static void findRepliesUsingAFilterExpression(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec().withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id").withFilterExpression("PostedBy = :v_postedby")
            .withValueMap(new ValueMap().withString(":v_id", replyId).withString(":v_postedby", "User B"));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesUsingAFilterExpression results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
    }
 

public static void main(String[] args) {

        AmazonDynamoDBClient client = new AmazonDynamoDBClient();
        client.setEndpoint("http://localhost:8000");
        DynamoDB dynamoDB = new DynamoDB(client);
   
        Table table = dynamoDB.getTable("Movies");
        
        ScanSpec scanSpec = new ScanSpec()
            .withProjectionExpression("#yr, title, info.rating")
            .withFilterExpression("#yr between :start_yr and :end_yr")
            .withNameMap(new NameMap().with("#yr",  "year"))
            .withValueMap(new ValueMap().withNumber(":start_yr", 1950).withNumber(":end_yr", 1959));
        
        ItemCollection<ScanOutcome> items = table.scan(scanSpec);
        
        Iterator<Item> iter = items.iterator();
        while (iter.hasNext()) {
            Item item = iter.next();
            System.out.println(item.toString());
        }
    }
 

@Override
public final Response query(final Request request) {

    Table table = dynamoDB.getTable(request.getTableName());

    final String keyConditionExpression = request.getPartitionKey() + "=:" + request.getPartitionKey();
            //+ " and " + request.getSortKey() + "=:" + request.getSortKey();

    QuerySpec querySpec = new QuerySpec()
            .withKeyConditionExpression(keyConditionExpression);

    final Map<String, Object> valueMap = new HashMap<>();
    StringBuilder filterExpressionBuilder;
    if (request.getFilterData() != null) {
        filterExpressionBuilder = new StringBuilder();
        processFilterData(request, filterExpressionBuilder, valueMap);
        //Add to QuerySpec.
        querySpec.withFilterExpression(filterExpressionBuilder.toString());
    }

    valueMap.put(":" + request.getPartitionKey(), request.getPartitionKeyValue());
    //valueMap.put(":" + request.getSortKey(), request.getSortKeyValue());
    querySpec.withValueMap(valueMap);

    ItemCollection<QueryOutcome> items = table.query(querySpec);

    StringBuilder response = new StringBuilder();
    response.append("PK of items read with query (V1): ");
    for (Item item : items) {
        response.append(prepareKeyStr(item, request));
    }

    return new Response(response.toString(), null);
}
 

private static void findRepliesPostedWithinTimePeriod(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long startDateMilli = (new Date()).getTime() - (15L*24L*60L*60L*1000L); 
        long endDateMilli = (new Date()).getTime() - (5L*24L*60L*60L*1000L);    
        java.text.SimpleDateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String startDate = df.format(startDateMilli);
        String endDate = df.format(endDateMilli);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime between :v_start_dt and :v_end_dt")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_start_dt", startDate)
                .withString(":v_end_dt", endDate));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesPostedWithinTimePeriod results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }    
    }
 

private static void findRepliesInLast15DaysWithConfig(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        long twoWeeksAgoMilli = (new Date()).getTime() - (15L*24L*60L*60L*1000L);
        Date twoWeeksAgo = new Date();
        twoWeeksAgo.setTime(twoWeeksAgoMilli);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        String twoWeeksAgoStr = df.format(twoWeeksAgo);
        
        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec()
            .withProjectionExpression("Message, ReplyDateTime, PostedBy")
            .withKeyConditionExpression("Id = :v_id and ReplyDateTime <= :v_reply_dt_tm")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId)
                .withString(":v_reply_dt_tm", twoWeeksAgoStr));
        
        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesInLast15DaysWithConfig results:");
        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }
 

private static void findRepliesForAThreadSpecifyOptionalLimit(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);
        
        String replyId = forumName + "#" + threadSubject;   
               
        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId))
            .withMaxPageSize(1);

        ItemCollection<QueryOutcome> items = table.query(spec);
        
        System.out.println("\nfindRepliesForAThreadSpecifyOptionalLimit results:");

        // Process each page of results
        int pageNum = 0;
        for (Page<Item, QueryOutcome> page : items.pages()) {
            
            System.out.println("\nPage: " + ++pageNum);

            // Process each item on the current page
            Iterator<Item> item = page.iterator();
            while (item.hasNext()) {
                System.out.println(item.next().toJSONPretty());
            }
        }
    }
 

@Override
public void run() {
    System.out.println("Scanning " + tableName + " segment " + segment + " out of " + totalSegments + " segments " + itemLimit + " items at a time...");
    int totalScannedItemCount = 0;

    Table table = dynamoDB.getTable(tableName);
    
    try {
        ScanSpec spec = new ScanSpec()
            .withMaxResultSize(itemLimit)
            .withTotalSegments(totalSegments)
            .withSegment(segment);
        
        ItemCollection<ScanOutcome> items = table.scan(spec);
        Iterator<Item> iterator = items.iterator();
          
        Item currentItem = null;
        while (iterator.hasNext()) {
            totalScannedItemCount++;
            currentItem = iterator.next();
            System.out.println(currentItem.toString());
        }    
            
    } catch (Exception e) {
        System.err.println(e.getMessage());
    } finally {
        System.out.println("Scanned " + totalScannedItemCount 
            + " items from segment " + segment + " out of " 
            + totalSegments + " of " + tableName);
    }
}
 

private static void findRepliesInLast15DaysWithConfig(
    String tableName, String forumName, String threadSubject) {

    String replyId = forumName + "#" + threadSubject;
    long twoWeeksAgoMilli = (new Date()).getTime()
        - (15L * 24L * 60L * 60L * 1000L);
    Date twoWeeksAgo = new Date();
    twoWeeksAgo.setTime(twoWeeksAgoMilli);
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    String twoWeeksAgoStr = df.format(twoWeeksAgo);

    Table table = dynamoDB.getTable(tableName);

    QuerySpec querySpec = new QuerySpec()
        .withKeyConditionExpression("Id = :v1 and ReplyDateTime > :v2")
        .withValueMap(new ValueMap()
            .withString(":v1", replyId)
            .withString(":v2", twoWeeksAgoStr))
        .withProjectionExpression("Message, ReplyDateTime, PostedBy");

    ItemCollection<QueryOutcome> items = table.query(querySpec);
    Iterator<Item> iterator = items.iterator();

    System.out.println("Query: printing results...");

    while (iterator.hasNext()) {
        System.out.println(iterator.next().toJSONPretty());
    }
}
 

@Override
public void run() {
    System.out.println("Scanning " + tableName + " segment " + segment + " out of " + totalSegments
        + " segments " + itemLimit + " items at a time...");
    int totalScannedItemCount = 0;

    Table table = dynamoDB.getTable(tableName);

    try {
        ScanSpec spec = new ScanSpec().withMaxResultSize(itemLimit).withTotalSegments(totalSegments)
            .withSegment(segment);

        ItemCollection<ScanOutcome> items = table.scan(spec);
        Iterator<Item> iterator = items.iterator();

        Item currentItem = null;
        while (iterator.hasNext()) {
            totalScannedItemCount++;
            currentItem = iterator.next();
            System.out.println(currentItem.toString());
        }

    }
    catch (Exception e) {
        System.err.println(e.getMessage());
    }
    finally {
        System.out.println("Scanned " + totalScannedItemCount + " items from segment " + segment + " out of "
            + totalSegments + " of " + tableName);
    }
}
 

public static void main(String[] args) throws Exception {

        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard()
            .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration("http://localhost:8000", "us-west-2"))
            .build();

        DynamoDB dynamoDB = new DynamoDB(client);

        Table table = dynamoDB.getTable("Movies");

        ScanSpec scanSpec = new ScanSpec().withProjectionExpression("#yr, title, info.rating")
            .withFilterExpression("#yr between :start_yr and :end_yr").withNameMap(new NameMap().with("#yr", "year"))
            .withValueMap(new ValueMap().withNumber(":start_yr", 1950).withNumber(":end_yr", 1959));

        try {
            ItemCollection<ScanOutcome> items = table.scan(scanSpec);

            Iterator<Item> iter = items.iterator();
            while (iter.hasNext()) {
                Item item = iter.next();
                System.out.println(item.toString());
            }

        }
        catch (Exception e) {
            System.err.println("Unable to scan the table:");
            System.err.println(e.getMessage());
        }
    }
 

void queryTest(String tableName, DynamoDB client, int pk, int sk1, int sk2, int iterations) {
    long startTime, endTime;
    System.out.println("Query test - partition key " + pk + " and sort keys between " + sk1 + " and " + sk2);
    Table table = client.getTable(tableName);

    HashMap<String, Object> valueMap = new HashMap<String, Object>();
    valueMap.put(":pkval", pk);
    valueMap.put(":skval1", sk1);
    valueMap.put(":skval2", sk2);

    QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("pk = :pkval and sk between :skval1 and :skval2")
            .withValueMap(valueMap);

    for (int i = 0; i < iterations; i++) {
        startTime = System.nanoTime();
        ItemCollection<QueryOutcome> items = table.query(spec);

        try {
            Iterator<Item> iter = items.iterator();
            while (iter.hasNext()) {
                iter.next();
            }
        } catch (Exception e) {
            System.err.println("Unable to query table:");
            e.printStackTrace();
        }
        endTime = System.nanoTime();
        printTime(startTime, endTime, iterations);
    }
}
 

@Override
public final Response scan(final Request request) {
    final Table table = dynamoDB.getTable(request.getTableName());

    final String projectionExpression = request.getPartitionKey() + " , " + request.getSortKey();
    final ScanSpec scanSpec = new ScanSpec()
            .withProjectionExpression(projectionExpression);

    StringBuilder filterExpressionBuilder;
    Map<String, Object> valueMap;
    if (request.getFilterData() != null) {
        filterExpressionBuilder = new StringBuilder();
        valueMap = new HashMap<>();
        processFilterData(request, filterExpressionBuilder, valueMap);
        // Add to ScanSpec.
        scanSpec.withFilterExpression(filterExpressionBuilder.toString());
        scanSpec.withValueMap(valueMap);
    }

    ItemCollection<ScanOutcome> scanItems = table.scan(scanSpec);

    final StringBuilder response = new StringBuilder();
    response.append("PK of items read with scan (V1): ");
    for (Item item : scanItems) {
        response.append(prepareKeyStr(item, request));
    }

    return new Response(response.toString(), null);
}
 

@Override
public Stream<DefaultInstalledAppContext> get() {
    Table table = dynamoDB.getTable(tableName);
    ItemCollection<ScanOutcome> scanItems = table.scan();
    Iterator<Item> iter = scanItems.iterator();
    Iterable<Item> iterable = () -> iter;
    return StreamSupport.stream(iterable.spliterator(), false)
        .map(item -> refreshed(contextFromItem(item)));
}
 

public static void main(String[] args)  {

        AmazonDynamoDBClient client = new AmazonDynamoDBClient();
        client.setEndpoint("http://localhost:8000");
        DynamoDB dynamoDB = new DynamoDB(client);
       
        Table table = dynamoDB.getTable("Movies");

        HashMap<String, String> nameMap = new HashMap<String, String>();
        nameMap.put("#yr", "year"); 
        
        HashMap<String, Object> valueMap = new HashMap<String, Object>();
        valueMap.put(":yyyy", 1985);
        
        QuerySpec querySpec = new QuerySpec()
            .withKeyConditionExpression("#yr = :yyyy")
            .withNameMap(new NameMap().with("#yr", "year"))
            .withValueMap(valueMap);

        ItemCollection<QueryOutcome> items = table.query(querySpec);

        Iterator<Item> iterator = items.iterator();
        Item item = null;

        System.out.println("Movies from 1985");
        while (iterator.hasNext()) {
            item = iterator.next();
            System.out.println(item.getNumber("year") + ": " + item.getString("title"));
        }
                        
        valueMap.put(":yyyy", 1992);
        valueMap.put(":letter1", "A");
        valueMap.put(":letter2", "L");
        
        querySpec
            .withProjectionExpression("#yr, title, info.genres, info.actors[0]")
            .withKeyConditionExpression("#yr = :yyyy and title between :letter1 and :letter2")
            .withNameMap(nameMap)
            .withValueMap(valueMap);
         
        items = table.query(querySpec);
        iterator = items.iterator();
        
        System.out.println("Movies from 1992 - titles A-L, with genres and lead actor");
        while (iterator.hasNext()) {
            item = iterator.next();
            System.out.println(item.toString());
        }
       
    }
 

public static void queryIndex(String indexName) {

        Table table = dynamoDB.getTable(tableName);

        System.out.println("\n***********************************************************\n");
        System.out.print("Querying index " + indexName + "...");

        Index index = table.getIndex(indexName);

        ItemCollection<QueryOutcome> items = null;

        QuerySpec querySpec = new QuerySpec();

        if (indexName == "CreateDateIndex") {
            System.out.println("Issues filed on 2013-11-01");
            querySpec.withKeyConditionExpression("CreateDate = :v_date and begins_with(IssueId, :v_issue)")
                .withValueMap(new ValueMap().withString(":v_date", "2013-11-01").withString(":v_issue", "A-"));
            items = index.query(querySpec);
        }
        else if (indexName == "TitleIndex") {
            System.out.println("Compilation errors");
            querySpec.withKeyConditionExpression("Title = :v_title and begins_with(IssueId, :v_issue)")
                .withValueMap(new ValueMap().withString(":v_title", "Compilation error").withString(":v_issue", "A-"));
            items = index.query(querySpec);
        }
        else if (indexName == "DueDateIndex") {
            System.out.println("Items that are due on 2013-11-30");
            querySpec.withKeyConditionExpression("DueDate = :v_date")
                .withValueMap(new ValueMap().withString(":v_date", "2013-11-30"));
            items = index.query(querySpec);
        }
        else {
            System.out.println("\nNo valid index name provided");
            return;
        }

        Iterator<Item> iterator = items.iterator();

        System.out.println("Query: printing results...");

        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }
 

private static void findRepliesForAThread(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;

        QuerySpec spec = new QuerySpec().withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap().withString(":v_id", replyId));

        ItemCollection<QueryOutcome> items = table.query(spec);

        System.out.println("\nfindRepliesForAThread results:");

        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }

    }
 

private static void findRepliesForAThread(String forumName, String threadSubject) {

        Table table = dynamoDB.getTable(tableName);

        String replyId = forumName + "#" + threadSubject;
        
        QuerySpec spec = new QuerySpec()
            .withKeyConditionExpression("Id = :v_id")
            .withValueMap(new ValueMap()
                .withString(":v_id", replyId));
        
        ItemCollection<QueryOutcome> items = table.query(spec);
        
        System.out.println("\nfindRepliesForAThread results:");

        Iterator<Item> iterator = items.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().toJSONPretty());
        }
        
    }
 

public static void queryIndex(String indexName) {
    
    Table table = dynamoDB.getTable(tableName);

    System.out.println
    ("\n***********************************************************\n");
    System.out.print("Querying index " + indexName + "...");

    Index index = table.getIndex(indexName);

    ItemCollection<QueryOutcome> items = null;
    
    QuerySpec querySpec = new QuerySpec();

    if (indexName == "CreateDateIndex") {
        System.out.println("Issues filed on 2013-11-01");
        querySpec.withKeyConditionExpression("CreateDate = :v_date and begins_with(IssueId, :v_issue)")
            .withValueMap(new ValueMap()
                .withString(":v_date","2013-11-01")
                .withString(":v_issue","A-"));
        items = index.query(querySpec);
    } else if (indexName == "TitleIndex") {
        System.out.println("Compilation errors");
        querySpec.withKeyConditionExpression("Title = :v_title and begins_with(IssueId, :v_issue)")
            .withValueMap(new ValueMap()
                .withString(":v_title","Compilation error")
                .withString(":v_issue","A-"));
        items = index.query(querySpec);
    } else if (indexName == "DueDateIndex") {
        System.out.println("Items that are due on 2013-11-30");
        querySpec.withKeyConditionExpression("DueDate = :v_date")
            .withValueMap(new ValueMap()
                .withString(":v_date","2013-11-30"));
        items = index.query(querySpec);
    } else {
        System.out.println("\nNo valid index name provided");
        return;
    }

    Iterator<Item> iterator = items.iterator();

    System.out.println("Query: printing results...");

    while (iterator.hasNext()) {
        System.out.println(iterator.next().toJSONPretty());
    }


}