TryDaxHelper.jawa

File TryDaxHelper.java berisi metode utilitas.

getDaxClientMetode getDynamoDBClient dan menyediakan klien Amazon DynamoDB dan DynamoDB Accelerator (). DAX Untuk operasi bidang kontrol (CreateTable, DeleteTable) dan operasi penulisan, program menggunakan klien DynamoDB. Jika Anda menentukan titik akhir DAX cluster, program utama membuat DAX klien untuk melakukan operasi baca (GetItem,Query,Scan).

Metode TryDaxHelper lainnya (createTable, writeData, deleteTable) digunakan untuk mengatur dan menghapus tabel DynamoDB dan datanya.

Anda dapat memodifikasi program dengan beberapa cara:

import com.amazon.dax.client.dynamodbv2.AmazonDaxClientBuilder;
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.Item;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.model.AttributeDefinition;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;
import com.amazonaws.services.dynamodbv2.model.ScalarAttributeType;
import com.amazonaws.util.EC2MetadataUtils;

public class TryDaxHelper {

    private static final String region = EC2MetadataUtils.getEC2InstanceRegion();

    DynamoDB getDynamoDBClient() {
        System.out.println("Creating a DynamoDB client");
        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard()
                .withRegion(region)
                .build();
        return new DynamoDB(client);
    }

    DynamoDB getDaxClient(String daxEndpoint) {
        System.out.println("Creating a DAX client with cluster endpoint " + daxEndpoint);
        AmazonDaxClientBuilder daxClientBuilder = AmazonDaxClientBuilder.standard();
        daxClientBuilder.withRegion(region).withEndpointConfiguration(daxEndpoint);
        AmazonDynamoDB client = daxClientBuilder.build();
        return new DynamoDB(client);
    }

    void createTable(String tableName, DynamoDB client) {
        Table table = client.getTable(tableName);
        try {
            System.out.println("Attempting to create table; please wait...");

            table = client.createTable(tableName,
                    Arrays.asList(
                            new KeySchemaElement("pk", KeyType.HASH), // Partition key
                            new KeySchemaElement("sk", KeyType.RANGE)), // Sort key
                    Arrays.asList(
                            new AttributeDefinition("pk", ScalarAttributeType.N),
                            new AttributeDefinition("sk", ScalarAttributeType.N)),
                    new ProvisionedThroughput(10L, 10L));
            table.waitForActive();
            System.out.println("Successfully created table.  Table status: " +
                    table.getDescription().getTableStatus());

        } catch (Exception e) {
            System.err.println("Unable to create table: ");
            e.printStackTrace();
        }
    }

    void writeData(String tableName, DynamoDB client, int pkmax, int skmax) {
        Table table = client.getTable(tableName);
        System.out.println("Writing data to the table...");

        int stringSize = 1000;
        StringBuilder sb = new StringBuilder(stringSize);
        for (int i = 0; i < stringSize; i++) {
            sb.append('X');
        }
        String someData = sb.toString();

        try {
            for (Integer ipk = 1; ipk <= pkmax; ipk++) {
                System.out.println(("Writing " + skmax + " items for partition key: " + ipk));
                for (Integer isk = 1; isk <= skmax; isk++) {
                    table.putItem(new Item()
                            .withPrimaryKey("pk", ipk, "sk", isk)
                            .withString("someData", someData));
                }
            }
        } catch (Exception e) {
            System.err.println("Unable to write item:");
            e.printStackTrace();
        }
    }

    void deleteTable(String tableName, DynamoDB client) {
        Table table = client.getTable(tableName);
        try {
            System.out.println("\nAttempting to delete table; please wait...");
            table.delete();
            table.waitForDelete();
            System.out.println("Successfully deleted table.");

        } catch (Exception e) {
            System.err.println("Unable to delete table: ");
            e.printStackTrace();
        }
    }

}