Contoh: Indeks Sekunder Global menggunakan API dokumen AWS SDK for Java

Contoh kode Java berikut menunjukkan cara menggunakan indeks sekunder global. Contoh tersebut membuat tabel bernama Issues, yang dapat digunakan dalam sistem pelacakan bug sederhana untuk pengembangan perangkat lunak. Kunci partisinya adalah IssueId dan kunci urutannya adalah Title. Ada tiga indeks sekunder global pada tabel ini:

• CreateDateIndex — Kunci partisinya adalah CreateDate dan kunci urutannya adalah IssueId. Selain kunci tabel, atribut Description dan Status diproyeksikan ke dalam indeks.

• TitleIndex — Kunci partisinya adalah Title dan kunci urutannya adalah IssueId. Tidak ada atribut selain kunci tabel yang diproyeksikan ke dalam indeks.

• DueDateIndex — Kunci partisinya adalah DueDate, dan tidak ada kunci urutan. Semua atribut tabel diproyeksikan ke dalam indeks.

Setelah tabel Issues dibuat, program memuat tabel dengan data yang mewakili laporan bug perangkat lunak. Kemudian, data dikueri menggunakan indeks sekunder global. Terakhir, program menghapus tabel Issues.

Untuk step-by-step instruksi untuk menguji contoh berikut, lihatContoh kode Java.

contoh

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.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.GlobalSecondaryIndex;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.Projection;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;

public class DocumentAPIGlobalSecondaryIndexExample {

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

    public static String tableName = "Issues";

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

        createTable();
        loadData();

        queryIndex("CreateDateIndex");
        queryIndex("TitleIndex");
        queryIndex("DueDateIndex");

        deleteTable(tableName);

    }

    public static void createTable() {

        // Attribute definitions
        ArrayList<AttributeDefinition> attributeDefinitions = new ArrayList<AttributeDefinition>();

        attributeDefinitions.add(new AttributeDefinition().withAttributeName("IssueId").withAttributeType("S"));
        attributeDefinitions.add(new AttributeDefinition().withAttributeName("Title").withAttributeType("S"));
        attributeDefinitions.add(new AttributeDefinition().withAttributeName("CreateDate").withAttributeType("S"));
        attributeDefinitions.add(new AttributeDefinition().withAttributeName("DueDate").withAttributeType("S"));

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

        // Initial provisioned throughput settings for the indexes
        ProvisionedThroughput ptIndex = new ProvisionedThroughput().withReadCapacityUnits(1L)
                .withWriteCapacityUnits(1L);

        // CreateDateIndex
        GlobalSecondaryIndex createDateIndex = new GlobalSecondaryIndex().withIndexName("CreateDateIndex")
                .withProvisionedThroughput(ptIndex)
                .withKeySchema(new KeySchemaElement().withAttributeName("CreateDate").withKeyType(KeyType.HASH), // Partition
                                                                                                                 // key
                        new KeySchemaElement().withAttributeName("IssueId").withKeyType(KeyType.RANGE)) // Sort
                                                                                                        // key
                .withProjection(
                        new Projection().withProjectionType("INCLUDE").withNonKeyAttributes("Description", "Status"));

        // TitleIndex
        GlobalSecondaryIndex titleIndex = new GlobalSecondaryIndex().withIndexName("TitleIndex")
                .withProvisionedThroughput(ptIndex)
                .withKeySchema(new KeySchemaElement().withAttributeName("Title").withKeyType(KeyType.HASH), // Partition
                                                                                                            // key
                        new KeySchemaElement().withAttributeName("IssueId").withKeyType(KeyType.RANGE)) // Sort
                                                                                                        // key
                .withProjection(new Projection().withProjectionType("KEYS_ONLY"));

        // DueDateIndex
        GlobalSecondaryIndex dueDateIndex = new GlobalSecondaryIndex().withIndexName("DueDateIndex")
                .withProvisionedThroughput(ptIndex)
                .withKeySchema(new KeySchemaElement().withAttributeName("DueDate").withKeyType(KeyType.HASH)) // Partition
                                                                                                              // key
                .withProjection(new Projection().withProjectionType("ALL"));

        CreateTableRequest createTableRequest = new CreateTableRequest().withTableName(tableName)
                .withProvisionedThroughput(
                        new ProvisionedThroughput().withReadCapacityUnits((long) 1).withWriteCapacityUnits((long) 1))
                .withAttributeDefinitions(attributeDefinitions).withKeySchema(tableKeySchema)
                .withGlobalSecondaryIndexes(createDateIndex, titleIndex, dueDateIndex);

        System.out.println("Creating table " + tableName + "...");
        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 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());
        }

    }

    public static void deleteTable(String tableName) {

        System.out.println("Deleting table " + tableName + "...");

        Table table = dynamoDB.getTable(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() {

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

        // IssueId, Title,
        // Description,
        // CreateDate, LastUpdateDate, DueDate,
        // Priority, Status

        putItem("A-101", "Compilation error", "Can't compile Project X - bad version number. What does this mean?",
                "2013-11-01", "2013-11-02", "2013-11-10", 1, "Assigned");

        putItem("A-102", "Can't read data file", "The main data file is missing, or the permissions are incorrect",
                "2013-11-01", "2013-11-04", "2013-11-30", 2, "In progress");

        putItem("A-103", "Test failure", "Functional test of Project X produces errors", "2013-11-01", "2013-11-02",
                "2013-11-10", 1, "In progress");

        putItem("A-104", "Compilation error", "Variable 'messageCount' was not initialized.", "2013-11-15",
                "2013-11-16", "2013-11-30", 3, "Assigned");

        putItem("A-105", "Network issue", "Can't ping IP address 127.0.0.1. Please fix this.", "2013-11-15",
                "2013-11-16", "2013-11-19", 5, "Assigned");

    }

    public static void putItem(

            String issueId, String title, String description, String createDate, String lastUpdateDate, String dueDate,
            Integer priority, String status) {

        Table table = dynamoDB.getTable(tableName);

        Item item = new Item().withPrimaryKey("IssueId", issueId).withString("Title", title)
                .withString("Description", description).withString("CreateDate", createDate)
                .withString("LastUpdateDate", lastUpdateDate).withString("DueDate", dueDate)
                .withNumber("Priority", priority).withString("Status", status);

        table.putItem(item);
    }

}