Ejemplo: índices secundarios locales mediante la API de documentos de Java - Amazon DynamoDB

Ejemplo: índices secundarios locales mediante la API de documentos de Java

En el siguiente ejemplo de código Java se muestra cómo usar índices secundarios locales en Amazon DynamoDB. En el ejemplo se crea una tabla denominada CustomerOrders cuya clave de partición es CustomerId y cuya clave de ordenación es OrderId. Hay dos índices secundarios locales en esta tabla:

  • OrderCreationDateIndex: la clave de ordenación es OrderCreationDate y los atributos siguientes se proyectan en el índice:

    • ProductCategory

    • ProductName

    • OrderStatus

    • ShipmentTrackingId

  • IsOpenIndex: la clave de ordenación es IsOpen y todos los atributos de la tabla se proyectan en el índice.

Después de que se crea la tabla CustomerOrders, el programa carga la tabla con datos que representan pedidos de clientes. A continuación, consulta los datos utilizando los índices secundarios locales. Por último, el programa elimina la tabla CustomerOrders.

Para obtener instrucciones paso a paso para probar el siguiente ejemplo, consulte Ejemplos de código Java.

ejemplo 

package com.amazonaws.codesamples.document;

import java.util.ArrayList;
import java.util.Iterator;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Index;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.ItemCollection;
import com.amazonaws.services.dynamodbv2.document.PutItemOutcome;
import com.amazonaws.services.dynamodbv2.document.QueryOutcome;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.document.spec.QuerySpec;
import com.amazonaws.services.dynamodbv2.document.utils.ValueMap;
import com.amazonaws.services.dynamodbv2.model.AttributeDefinition;
import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.LocalSecondaryIndex;
import com.amazonaws.services.dynamodbv2.model.Projection;
import com.amazonaws.services.dynamodbv2.model.ProjectionType;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;
import com.amazonaws.services.dynamodbv2.model.ReturnConsumedCapacity;
import com.amazonaws.services.dynamodbv2.model.Select;

public class DocumentAPILocalSecondaryIndexExample {

        static AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().build();
        static DynamoDB dynamoDB = new DynamoDB(client);

        public static String tableName = "CustomerOrders";

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

                createTable();
                loadData();

                query(null);
                query("IsOpenIndex");
                query("OrderCreationDateIndex");

                deleteTable(tableName);

        }

        public static void createTable() {

                CreateTableRequest createTableRequest = new CreateTableRequest().withTableName(tableName)
                                .withProvisionedThroughput(
                                                new ProvisionedThroughput().withReadCapacityUnits((long) 1)
                                                                .withWriteCapacityUnits((long) 1));

                // Attribute definitions for table partition and sort keys
                ArrayList<AttributeDefinition> attributeDefinitions = new ArrayList<AttributeDefinition>();
                attributeDefinitions
                                .add(new AttributeDefinition().withAttributeName("CustomerId").withAttributeType("S"));
                attributeDefinitions.add(new AttributeDefinition().withAttributeName("OrderId").withAttributeType("N"));

                // Attribute definition for index primary key attributes
                attributeDefinitions
                                .add(new AttributeDefinition().withAttributeName("OrderCreationDate")
                                                .withAttributeType("N"));
                attributeDefinitions.add(new AttributeDefinition().withAttributeName("IsOpen").withAttributeType("N"));

                createTableRequest.setAttributeDefinitions(attributeDefinitions);

                // Key schema for table
                ArrayList<KeySchemaElement> tableKeySchema = new ArrayList<KeySchemaElement>();
                tableKeySchema.add(new KeySchemaElement().withAttributeName("CustomerId").withKeyType(KeyType.HASH)); // Partition
                                                                                                                      // key
                tableKeySchema.add(new KeySchemaElement().withAttributeName("OrderId").withKeyType(KeyType.RANGE)); // Sort
                                                                                                                    // key

                createTableRequest.setKeySchema(tableKeySchema);

                ArrayList<LocalSecondaryIndex> localSecondaryIndexes = new ArrayList<LocalSecondaryIndex>();

                // OrderCreationDateIndex
                LocalSecondaryIndex orderCreationDateIndex = new LocalSecondaryIndex()
                                .withIndexName("OrderCreationDateIndex");

                // Key schema for OrderCreationDateIndex
                ArrayList<KeySchemaElement> indexKeySchema = new ArrayList<KeySchemaElement>();
                indexKeySchema.add(new KeySchemaElement().withAttributeName("CustomerId").withKeyType(KeyType.HASH)); // Partition
                                                                                                                      // key
                indexKeySchema.add(new KeySchemaElement().withAttributeName("OrderCreationDate")
                                .withKeyType(KeyType.RANGE)); // Sort
                                                              // key

                orderCreationDateIndex.setKeySchema(indexKeySchema);

                // Projection (with list of projected attributes) for
                // OrderCreationDateIndex
                Projection projection = new Projection().withProjectionType(ProjectionType.INCLUDE);
                ArrayList<String> nonKeyAttributes = new ArrayList<String>();
                nonKeyAttributes.add("ProductCategory");
                nonKeyAttributes.add("ProductName");
                projection.setNonKeyAttributes(nonKeyAttributes);

                orderCreationDateIndex.setProjection(projection);

                localSecondaryIndexes.add(orderCreationDateIndex);

                // IsOpenIndex
                LocalSecondaryIndex isOpenIndex = new LocalSecondaryIndex().withIndexName("IsOpenIndex");

                // Key schema for IsOpenIndex
                indexKeySchema = new ArrayList<KeySchemaElement>();
                indexKeySchema.add(new KeySchemaElement().withAttributeName("CustomerId").withKeyType(KeyType.HASH)); // Partition
                                                                                                                      // key
                indexKeySchema.add(new KeySchemaElement().withAttributeName("IsOpen").withKeyType(KeyType.RANGE)); // Sort
                                                                                                                   // key

                // Projection (all attributes) for IsOpenIndex
                projection = new Projection().withProjectionType(ProjectionType.ALL);

                isOpenIndex.setKeySchema(indexKeySchema);
                isOpenIndex.setProjection(projection);

                localSecondaryIndexes.add(isOpenIndex);

                // Add index definitions to CreateTable request
                createTableRequest.setLocalSecondaryIndexes(localSecondaryIndexes);

                System.out.println("Creating table " + tableName + "...");
                System.out.println(dynamoDB.createTable(createTableRequest));

                // Wait for table to become active
                System.out.println("Waiting for " + tableName + " to become ACTIVE...");
                try {
                        Table table = dynamoDB.getTable(tableName);
                        table.waitForActive();
                } catch (InterruptedException e) {
                        e.printStackTrace();
                }
        }

        public static void query(String indexName) {

                Table table = dynamoDB.getTable(tableName);

                System.out.println("\n***********************************************************\n");
                System.out.println("Querying table " + tableName + "...");

                QuerySpec querySpec = new QuerySpec().withConsistentRead(true).withScanIndexForward(true)
                                .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);

                if (indexName == "IsOpenIndex") {

                        System.out.println("\nUsing index: '" + indexName + "': Bob's orders that are open.");
                        System.out.println("Only a user-specified list of attributes are returned\n");
                        Index index = table.getIndex(indexName);

                        querySpec.withKeyConditionExpression("CustomerId = :v_custid and IsOpen = :v_isopen")
                                        .withValueMap(new ValueMap().withString(":v_custid", "[email protected]")
                                                        .withNumber(":v_isopen", 1));

                        querySpec.withProjectionExpression(
                                        "OrderCreationDate, ProductCategory, ProductName, OrderStatus");

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

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

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

                } else if (indexName == "OrderCreationDateIndex") {
                        System.out.println("\nUsing index: '" + indexName
                                        + "': Bob's orders that were placed after 01/31/2015.");
                        System.out.println("Only the projected attributes are returned\n");
                        Index index = table.getIndex(indexName);

                        querySpec.withKeyConditionExpression(
                                        "CustomerId = :v_custid and OrderCreationDate >= :v_orddate")
                                        .withValueMap(
                                                        new ValueMap().withString(":v_custid", "[email protected]")
                                                                        .withNumber(":v_orddate",
                                                                                        20150131));

                        querySpec.withSelect(Select.ALL_PROJECTED_ATTRIBUTES);

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

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

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

                } else {
                        System.out.println("\nNo index: All of Bob's orders, by OrderId:\n");

                        querySpec.withKeyConditionExpression("CustomerId = :v_custid")
                                        .withValueMap(new ValueMap().withString(":v_custid", "[email protected]"));

                        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());
                        }

                }

        }

        public static void deleteTable(String tableName) {

                Table table = dynamoDB.getTable(tableName);
                System.out.println("Deleting table " + tableName + "...");
                table.delete();

                // Wait for table to be deleted
                System.out.println("Waiting for " + tableName + " to be deleted...");
                try {
                        table.waitForDelete();
                } catch (InterruptedException e) {
                        e.printStackTrace();
                }
        }

        public static void loadData() {

                Table table = dynamoDB.getTable(tableName);

                System.out.println("Loading data into table " + tableName + "...");

                Item item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 1)
                                .withNumber("IsOpen", 1).withNumber("OrderCreationDate", 20150101)
                                .withString("ProductCategory", "Book")
                                .withString("ProductName", "The Great Outdoors")
                                .withString("OrderStatus", "PACKING ITEMS");
                // no ShipmentTrackingId attribute

                PutItemOutcome putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 2)
                                .withNumber("IsOpen", 1).withNumber("OrderCreationDate", 20150221)
                                .withString("ProductCategory", "Bike")
                                .withString("ProductName", "Super Mountain")
                                .withString("OrderStatus", "ORDER RECEIVED");
                // no ShipmentTrackingId attribute

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 3)
                                // no IsOpen attribute
                                .withNumber("OrderCreationDate", 20150304).withString("ProductCategory", "Music")
                                .withString("ProductName", "A Quiet Interlude").withString("OrderStatus", "IN TRANSIT")
                                .withString("ShipmentTrackingId", "176493");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 1)
                                // no IsOpen attribute
                                .withNumber("OrderCreationDate", 20150111).withString("ProductCategory", "Movie")
                                .withString("ProductName", "Calm Before The Storm")
                                .withString("OrderStatus", "SHIPPING DELAY")
                                .withString("ShipmentTrackingId", "859323");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 2)
                                // no IsOpen attribute
                                .withNumber("OrderCreationDate", 20150124).withString("ProductCategory", "Music")
                                .withString("ProductName", "E-Z Listening").withString("OrderStatus", "DELIVERED")
                                .withString("ShipmentTrackingId", "756943");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 3)
                                // no IsOpen attribute
                                .withNumber("OrderCreationDate", 20150221).withString("ProductCategory", "Music")
                                .withString("ProductName", "Symphony 9").withString("OrderStatus", "DELIVERED")
                                .withString("ShipmentTrackingId", "645193");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 4)
                                .withNumber("IsOpen", 1).withNumber("OrderCreationDate", 20150222)
                                .withString("ProductCategory", "Hardware")
                                .withString("ProductName", "Extra Heavy Hammer")
                                .withString("OrderStatus", "PACKING ITEMS");
                // no ShipmentTrackingId attribute

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 5)
                                /* no IsOpen attribute */
                                .withNumber("OrderCreationDate", 20150309).withString("ProductCategory", "Book")
                                .withString("ProductName", "How To Cook").withString("OrderStatus", "IN TRANSIT")
                                .withString("ShipmentTrackingId", "440185");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 6)
                                // no IsOpen attribute
                                .withNumber("OrderCreationDate", 20150318).withString("ProductCategory", "Luggage")
                                .withString("ProductName", "Really Big Suitcase").withString("OrderStatus", "DELIVERED")
                                .withString("ShipmentTrackingId", "893927");

                putItemOutcome = table.putItem(item);

                item = new Item().withPrimaryKey("CustomerId", "[email protected]").withNumber("OrderId", 7)
                                /* no IsOpen attribute */
                                .withNumber("OrderCreationDate", 20150324).withString("ProductCategory", "Golf")
                                .withString("ProductName", "PGA Pro II").withString("OrderStatus", "OUT FOR DELIVERY")
                                .withString("ShipmentTrackingId", "383283");

                putItemOutcome = table.putItem(item);
                assert putItemOutcome != null;
        }

}