例: AWS SDK for Java ドキュメント API を使用したグローバルセカンダリインデックス - Amazon DynamoDB

例: AWS SDK for Java ドキュメント API を使用したグローバルセカンダリインデックス

次の Java コード例は、グローバルセカンダリインデックスの操作方法を示しています。この例では、Issues というテーブルを作成しています。これは、ソフトウェア開発のためのシンプルなバグ追跡システムで使用できる可能性があります。パーティションキーは IssueId で、ソートキーは Title です。このテーブルには、次の 3 つのグローバルセカンダリインデックスがあります。

  • CreateDateIndex – パーティションキーは CreateDate で、ソートキーは IssueId です。テーブルキーに加えて、属性 Description および Status はインデックスに射影されます。

  • TitleIndex – パーティションキーは Title で、ソートキーは IssueId です。テーブルキー以外の属性はインデックスに射影されません。

  • DueDateIndex – パーティションキーは DueDate で、ソートキーはありません。すべてのテーブル属性がインデックスに射影されます。

Issues テーブルが作成されると、プログラムはソフトウェアのバグレポートを表すデータをテーブルにロードします。次に、グローバルセカンダリインデックスを使用してデータのクエリを実行します。最後に、プログラムは Issues テーブルを削除します。

以下の例をテストするための詳細な手順については、「Java コードの例」を参照してください。

例 

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);
    }

}