import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
private static Page<Item, QueryOutcome> queryGSI(String appid, Pager p) {
	Pager pager = (p != null) ? p : new Pager();
	Index index = getSharedIndex();
	QuerySpec spec = new QuerySpec().
			withMaxPageSize(pager.getLimit()).
			withMaxResultSize(pager.getLimit()).
			withKeyConditionExpression(Config._APPID + " = :aid").
			withValueMap(new ValueMap().withString(":aid", appid));

	if (!StringUtils.isBlank(pager.getLastKey())) {
		spec = spec.withExclusiveStartKey(new KeyAttribute(Config._APPID, appid),	// HASH/PARTITION KEY
				new KeyAttribute(Config._ID, pager.getLastKey()), // RANGE/SORT KEY
				new KeyAttribute(Config._KEY, getKeyForAppid(pager.getLastKey(), appid))); // TABLE PRIMARY KEY
	}
	return index != null ? index.query(spec).firstPage() : null;
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
@Override public boolean queryRelationExists(String relationHashKey, String relationRangeKey) {

    Table table = dynamoDB.getTable(this.groupGraphTableName);

    QuerySpec querySpec = new QuerySpec()
        .withKeyConditionExpression("subject = :k_subject and object_relation = :k_object_relation")
        .withValueMap(new ValueMap()
            .withString(":k_subject", relationHashKey)
            .withString(":k_object_relation", relationRangeKey)
        )
        .withMaxResultSize(1)
        .withConsistentRead(true);

    DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("queryRelation",
        () -> queryTable(table, querySpec),
        () -> {
          throw new RuntimeException("queryRelation");
        },
        dynamodbNamespaceGraphQueryHystrix,
        metrics);

    // can't use getLastLowLevelResult directly; it's false unless the outcome is iterated first :|
    return cmd.execute().iterator().hasNext();
  }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
        }    
     }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
@Override public Optional<Group> loadByKey(String key) {
  Table table = dynamoDB.getTable(this.groupTableName);

  QuerySpec querySpec = new QuerySpec()
      .withKeyConditionExpression(HASH_KEY + " = :k_app_key")
      .withValueMap(new ValueMap()
          .withString(":k_app_key", key)
      )
      .withMaxResultSize(1)
      .withConsistentRead(true);

  DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("loadByKey",
      () -> queryTable(table, querySpec),
      () -> {
        throw new RuntimeException("loadByKey");
      },
      dynamodbNamespaceGraphQueryHystrix,
      metrics);

  final ItemCollection<QueryOutcome> items = cmd.execute();
  final IteratorSupport<Item, QueryOutcome> iterator = items.iterator();
  if (iterator.hasNext()) {
    return Optional.of(GroupSupport.toGroup(iterator.next().getString("json")));
  }

  return Optional.empty();
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
@Override public List<Feature> loadFeatures(String group) {
  logger.info("{}", kvp("op", "loadFeatures", "group", group));
  List<Feature> features = Lists.newArrayList();

  Table table = dynamoDB.getTable(featureTableName);

  QuerySpec querySpec = new QuerySpec()
      .withKeyConditionExpression(HASH_KEY + " = :k_" + HASH_KEY)
      .withValueMap(new ValueMap().withString(":k_" + HASH_KEY, group))
      .withConsistentRead(true);

  DynamoDbCommand<ItemCollection<QueryOutcome>> cmd = new DynamoDbCommand<>("loadFeatures",
      () -> queryTable(table, querySpec),
      () -> {
        throw new RuntimeException("loadFeatureById");
      },
      hystrixReadConfiguration,
      metrics);

  ItemCollection<QueryOutcome> items = cmd.execute();

  for (Page<Item, QueryOutcome> page : items.pages()) {
    page.forEach(item -> features.add(FeatureSupport.toFeature(item.getString("json"))));
  }

  return features;
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
@Override
public List<String> retrieveRecordsForProvince(String dataSetLabel, String infoSetTag, Province province, Locale locale) {
    if (!useDynamoDirect) {
        URI uriToCall = baseBuilder()
                .path("/records/{dataset}/{infoSet}")
                .queryParam("province", province.toString())
                .queryParam("locale", locale.toLanguageTag())
                .buildAndExpand(dataSetLabel, infoSetTag).toUri();

        log.info("assembled URI to get records = {}", uriToCall.toString());

        return getFromUri(uriToCall);
    } else {
        DynamoDB dynamoDB = new DynamoDB(dynamoDBClient);
        Table geoApiTable = dynamoDB.getTable("geo_" + dataSetLabel.toLowerCase());
        log.info("querying from table, name: {}, number of rows: {}",
                "geo_" + dataSetLabel.toLowerCase(), geoApiTable.describe().toString());
        log.info("looking for province, with name: {}, on infoSet: {}", province.name(), infoSetTag);

        Index provinceIndex = geoApiTable.getIndex("lowestGeoInfo"); // figure out how to adapt when province != lowest
        QuerySpec querySpec = new QuerySpec()
                .withKeyConditionExpression("province = :prv and infoTag = :info")
                .withValueMap(new ValueMap()
                        .withString(":prv", province.name())
                        .withString(":info", infoSetTag));

        try {
            ItemCollection<QueryOutcome> records = provinceIndex.query(querySpec);
            List<String> result = new ArrayList<>();
            records.iterator().forEachRemaining(i -> result.add(i.getString("description")));
            log.info("iterated through the results, number of results: {}", result.size());
            return result;
        } catch (Exception e) {
            log.error("Error!", e);
            throw new IllegalArgumentException("No results for that dataset, province and field");
        }
    }
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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");
                
        // Conditional delete (will fail)
        
        DeleteItemSpec deleteItemSpec = new DeleteItemSpec()
            .withPrimaryKey(new PrimaryKey("year", 2015, "title", "The Big New Movie"))
            .withConditionExpression("info.rating <= :val")
            .withValueMap(new ValueMap()
                   .withNumber(":val", 5.0));
        
        System.out.println("Attempting a conditional delete...");
        try {
            table.deleteItem(deleteItemSpec);
            System.out.println("DeleteItem succeeded");
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("DeleteItem failed");
        }

    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
        }
    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
private static void deleteItem() {

        Table table = dynamoDB.getTable(tableName);

        try {

            DeleteItemSpec deleteItemSpec = new DeleteItemSpec()
            .withPrimaryKey("Id", 120)
            .withConditionExpression("#ip = :val")
            .withNameMap(new NameMap()
                .with("#ip", "InPublication"))
            .withValueMap(new ValueMap()
            .withBoolean(":val", false))
            .withReturnValues(ReturnValue.ALL_OLD);

            DeleteItemOutcome outcome = table.deleteItem(deleteItemSpec);

            // Check the response.
            System.out.println("Printing item that was deleted...");
            System.out.println(outcome.getItem().toJSONPretty());

        } catch (Exception e) {
            System.err.println("Error deleting item in " + tableName);
            System.err.println(e.getMessage());
        }
    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
@Override
public void announce(long stateVersion) {
    Table table = dynamoDB.getTable(tableName);

    UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey("namespace", blobNamespace)
            .withUpdateExpression("set #version = :ver")
            .withNameMap(new NameMap().with("#version", "version"))
            .withValueMap(new ValueMap().withNumber(":ver", stateVersion));

    table.updateItem(updateItemSpec);
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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");
        
        int year = 2015;
        String title = "The Big New Movie";

        // Conditional update (will fail)

        UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey(new PrimaryKey("year", 2015, "title",  "The Big New Movie"))
            .withUpdateExpression("remove info.actors[0]")
            .withConditionExpression("size(info.actors) > :num")
            .withValueMap(new ValueMap().withNumber(":num", 3));

        System.out.println("Attempting a conditional update...");
        try {
            table.updateItem(updateItemSpec);
            System.out.println("UpdateItem succeeded: " + table.getItem("year", year, "title", title).toJSONPretty());
        } catch (ConditionalCheckFailedException e) {
            e.printStackTrace();
            System.out.println("UpdateItem failed");
        }

    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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");
        
        int year = 2015;
        String title = "The Big New Movie";
        
        UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey("year", year, "title", title)
            .withUpdateExpression("set info.rating = info.rating + :val")
            .withValueMap(new ValueMap()
                .withNumber(":val", 1));

        System.out.println("Incrementing an atomic counter...");
        try {
            table.updateItem(updateItemSpec);
            System.out.println("UpdateItem succeeded: " + table.getItem("year", year, "title", title).toJSONPretty());
        } catch (Exception e) {
            System.out.println("UpdateItem failed");
            e.printStackTrace();
        }

    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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");
        
        int year = 2015;
        String title = "The Big New Movie";

        UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey("year", year, "title", title)
            .withUpdateExpression("set info.rating = :r, info.plot=:p, info.actors=:a")
            .withValueMap(new ValueMap()
                .withNumber(":r", 5.5)
                .withString(":p", "Everything happens all at once.")
                .withList(":a", Arrays.asList("Larry","Moe","Curly")));

        System.out.println("Updating the item...");
        try {
            table.updateItem(updateItemSpec);
            System.out.println("UpdateItem succeeded: " + table.getItem("year", year, "title", title).toJSONPretty());
        } catch (Exception e) {
            System.out.println("UpdateItem failed");
            e.printStackTrace();
        }
                

    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
    }
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
private static void updateAddNewAttribute() {
    Table table = dynamoDB.getTable(tableName);

    try {

        Map<String, String> expressionAttributeNames = new HashMap<String, String>();
        expressionAttributeNames.put("#na", "NewAttribute");

        UpdateItemSpec updateItemSpec = new UpdateItemSpec()
        .withPrimaryKey("Id", 121)
        .withUpdateExpression("set #na = :val1")
        .withNameMap(new NameMap()
            .with("#na", "NewAttribute"))
        .withValueMap(new ValueMap()
            .withString(":val1", "Some value"))
        .withReturnValues(ReturnValue.ALL_NEW);

        UpdateItemOutcome outcome =  table.updateItem(updateItemSpec);

        // Check the response.
        System.out.println("Printing item after adding new attribute...");
        System.out.println(outcome.getItem().toJSONPretty());           

    }   catch (Exception e) {
        System.err.println("Failed to add new attribute in " + tableName);
        System.err.println(e.getMessage());
    }        
}
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
private static void updateMultipleAttributes() {

        Table table = dynamoDB.getTable(tableName);

        try {

           UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey("Id", 120)
            .withUpdateExpression("add #a :val1 set #na=:val2")
            .withNameMap(new NameMap()
                .with("#a", "Authors")
                .with("#na", "NewAttribute"))
            .withValueMap(new ValueMap()
                .withStringSet(":val1", "Author YY", "Author ZZ")
                .withString(":val2", "someValue"))
            .withReturnValues(ReturnValue.ALL_NEW);

            UpdateItemOutcome outcome = table.updateItem(updateItemSpec);

            // Check the response.
            System.out
            .println("Printing item after multiple attribute update...");
            System.out.println(outcome.getItem().toJSONPretty());

        } catch (Exception e) {
            System.err.println("Failed to update multiple attributes in "
                    + tableName);
            System.err.println(e.getMessage());

        }
    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
private static void updateExistingAttributeConditionally() {

        Table table = dynamoDB.getTable(tableName);

        try {

            // Specify the desired price (25.00) and also the condition (price =
            // 20.00)

            UpdateItemSpec updateItemSpec = new UpdateItemSpec()
            .withPrimaryKey("Id", 120)
            .withReturnValues(ReturnValue.ALL_NEW)
            .withUpdateExpression("set #p = :val1")
            .withConditionExpression("#p = :val2")
            .withNameMap(new NameMap()
                .with("#p", "Price"))
            .withValueMap(new ValueMap()
                .withNumber(":val1", 25)
                .withNumber(":val2", 20));

            UpdateItemOutcome outcome = table.updateItem(updateItemSpec);

            // Check the response.
            System.out
            .println("Printing item after conditional update to new attribute...");
            System.out.println(outcome.getItem().toJSONPretty());

        } catch (Exception e) {
            System.err.println("Error updating item in " + tableName);
            System.err.println(e.getMessage());
        }
    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
            }
        }
    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
        }

    }
 

import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; //导入依赖的package包/类
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());
        }    
    }