LowLevelTableExample.java

/*
* Copyright 2014-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
*  http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package com.amazonaws.codesamples.lowlevel;

import java.util.ArrayList;

import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.model.AttributeDefinition;
import com.amazonaws.services.dynamodbv2.model.CreateTableRequest;
import com.amazonaws.services.dynamodbv2.model.DeleteTableRequest;
import com.amazonaws.services.dynamodbv2.model.DescribeTableRequest;
import com.amazonaws.services.dynamodbv2.model.KeySchemaElement;
import com.amazonaws.services.dynamodbv2.model.KeyType;
import com.amazonaws.services.dynamodbv2.model.ListTablesRequest;
import com.amazonaws.services.dynamodbv2.model.ListTablesResult;
import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput;
import com.amazonaws.services.dynamodbv2.model.ResourceNotFoundException;
import com.amazonaws.services.dynamodbv2.model.TableDescription;
import com.amazonaws.services.dynamodbv2.model.TableStatus;
import com.amazonaws.services.dynamodbv2.model.UpdateTableRequest;

public class LowLevelTableExample {

    static AmazonDynamoDBClient client = new AmazonDynamoDBClient(new ProfileCredentialsProvider());
    static String tableName = "ExampleTable";

    public static void main(String[] args) throws Exception {
               
        createExampleTable();
        listMyTables();
        getTableInformation();
        updateExampleTable();
        
        deleteExampleTable();
    }

    static void createExampleTable() {
                
        
        // Provide the initial provisioned throughput values as Java long data types
        ProvisionedThroughput provisionedThroughput = new ProvisionedThroughput()
            .withReadCapacityUnits(5L)
            .withWriteCapacityUnits(6L);
        CreateTableRequest request = new CreateTableRequest()
            .withTableName(tableName)
            .withProvisionedThroughput(provisionedThroughput);
        
        ArrayList<AttributeDefinition> attributeDefinitions= new ArrayList<AttributeDefinition>();
        attributeDefinitions.add(new AttributeDefinition().withAttributeName("Id").withAttributeType("N"));
        request.setAttributeDefinitions(attributeDefinitions);
        
        ArrayList<KeySchemaElement> tableKeySchema = new ArrayList<KeySchemaElement>();
        tableKeySchema.add(new KeySchemaElement().withAttributeName("Id").withKeyType(KeyType.HASH));
        request.setKeySchema(tableKeySchema);
  
        client.createTable(request);
        
        waitForTableToBecomeAvailable(tableName); 

        getTableInformation();
        
    }

    static void listMyTables() {
        String lastEvaluatedTableName = null;
        do {
            
            ListTablesRequest listTablesRequest = new ListTablesRequest()
            .withLimit(10)
            .withExclusiveStartTableName(lastEvaluatedTableName);
            
            ListTablesResult result = client.listTables(listTablesRequest);
            lastEvaluatedTableName = result.getLastEvaluatedTableName();
            
            for (String name : result.getTableNames()) {
                System.out.println(name);
            }
            
        } while (lastEvaluatedTableName != null);
    }

    static void getTableInformation() {
        
        TableDescription tableDescription = client.describeTable(
                new DescribeTableRequest().withTableName(tableName)).getTable();
        System.out.format("Name: %s:\n" +
                "Status: %s \n" + 
                "Provisioned Throughput (read capacity units/sec): %d \n" +
                "Provisioned Throughput (write capacity units/sec): %d \n",
                tableDescription.getTableName(),
                tableDescription.getTableStatus(),
                tableDescription.getProvisionedThroughput().getReadCapacityUnits(),
                tableDescription.getProvisionedThroughput().getWriteCapacityUnits());
    }

    static void updateExampleTable() {
        
        ProvisionedThroughput provisionedThroughput = new ProvisionedThroughput()
        .withReadCapacityUnits(6L)
        .withWriteCapacityUnits(7L);

        UpdateTableRequest updateTableRequest = new UpdateTableRequest()
            .withTableName(tableName)
            .withProvisionedThroughput(provisionedThroughput);
        
        client.updateTable(updateTableRequest);
        waitForTableToBecomeAvailable(tableName);
    }

    static void deleteExampleTable() {
        DeleteTableRequest deleteTableRequest = new DeleteTableRequest()
            .withTableName(tableName);
        client.deleteTable(deleteTableRequest);
        waitForTableToBeDeleted(tableName);  
    }

    private static void waitForTableToBecomeAvailable(String tableName) {
        System.out.println("Waiting for " + tableName + " to become ACTIVE...");

        long startTime = System.currentTimeMillis();
        long endTime = startTime + (10 * 60 * 1000);
        while (System.currentTimeMillis() < endTime) {
            DescribeTableRequest request = new DescribeTableRequest()
                    .withTableName(tableName);
            TableDescription tableDescription = client.describeTable(
                    request).getTable();
            String tableStatus = tableDescription.getTableStatus();
            System.out.println("  - current state: " + tableStatus);
            if (tableStatus.equals(TableStatus.ACTIVE.toString()))
                return;
            try { Thread.sleep(1000 * 20); } catch (Exception e) { }
        }
        throw new RuntimeException("Table " + tableName + " never went active");
    }
    
    private static void waitForTableToBeDeleted(String tableName) {
        System.out.println("Waiting for " + tableName + " while status DELETING...");

        long startTime = System.currentTimeMillis();
        long endTime = startTime + (10 * 60 * 1000);
        while (System.currentTimeMillis() < endTime) {
            try {
                DescribeTableRequest request = new DescribeTableRequest().withTableName(tableName);
                TableDescription tableDescription = client.describeTable(request).getTable();
                String tableStatus = tableDescription.getTableStatus();
                System.out.println("  - current state: " + tableStatus);
                if (tableStatus.equals(TableStatus.ACTIVE.toString())) return;
            } catch (ResourceNotFoundException e) {
                System.out.println("Table " + tableName + " is not found. It was deleted.");
                return;
            }
            try {Thread.sleep(1000 * 20);} catch (Exception e) {}
        }
        throw new RuntimeException("Table " + tableName + " was never deleted");
    }

}