Java tutorial
package cs.iit.edu.ckmr.worker; /* * Copyright 2012-2013 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. */ import java.util.List; import com.amazonaws.AmazonClientException; import com.amazonaws.AmazonServiceException; import com.amazonaws.auth.ClasspathPropertiesFileCredentialsProvider; import com.amazonaws.regions.Region; import com.amazonaws.regions.Regions; 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.ListTablesResult; import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput; import com.amazonaws.services.dynamodbv2.model.ScalarAttributeType; import com.amazonaws.services.dynamodbv2.model.TableDescription; import com.amazonaws.services.dynamodbv2.model.TableStatus; public class TableCreator { static AmazonDynamoDBClient dynamoDB; public TableCreator() { dynamoDB = new AmazonDynamoDBClient(new ClasspathPropertiesFileCredentialsProvider()); Region usEast1 = Region.getRegion(Regions.US_EAST_1); dynamoDB.setRegion(usEast1); } public void createTable(long readCapacity, long writeCapacity, String tableName) { // Create a table with a primary hash key named 'name', which holds // a string CreateTableRequest createTableRequest = new CreateTableRequest().withTableName(tableName) .withKeySchema(new KeySchemaElement().withAttributeName("messageId").withKeyType(KeyType.HASH)) .withAttributeDefinitions(new AttributeDefinition().withAttributeName("messageId") .withAttributeType(ScalarAttributeType.S)) .withProvisionedThroughput(new ProvisionedThroughput().withReadCapacityUnits(readCapacity) .withWriteCapacityUnits(writeCapacity)); TableDescription createdTableDescription = dynamoDB.createTable(createTableRequest).getTableDescription(); System.out.println("Created Table: " + createdTableDescription); // Wait for it to become active waitForTableToBecomeAvailable(tableName); // Describe our new table DescribeTableRequest describeTableRequest = new DescribeTableRequest().withTableName(tableName); TableDescription tableDescription = dynamoDB.describeTable(describeTableRequest).getTable(); System.out.println("Table Description: " + tableDescription); } public void deleteTable(String tableName) { DeleteTableRequest deleteTableRequest = new DeleteTableRequest(tableName); dynamoDB.deleteTable(deleteTableRequest); waitForTableToDelete(tableName); } public void initializeTable(long readCapacity, long writeCapacity) { try { String tableName = "messages"; ListTablesResult listTableResult = new ListTablesResult(); listTableResult = dynamoDB.listTables(); List<String> tableNames = listTableResult.getTableNames(); if (!tableNames.contains(tableName)) { createTable(readCapacity, writeCapacity, tableName); } } catch (AmazonServiceException ase) { System.out.println("Caught an AmazonServiceException, which means your request made it " + "to AWS, but was rejected with an error response for some reason."); System.out.println("Error Message: " + ase.getMessage()); System.out.println("HTTP Status Code: " + ase.getStatusCode()); System.out.println("AWS Error Code: " + ase.getErrorCode()); System.out.println("Error Type: " + ase.getErrorType()); System.out.println("Request ID: " + ase.getRequestId()); } catch (AmazonClientException ace) { System.out.println("Caught an AmazonClientException, which means the client encountered " + "a serious internal problem while trying to communicate with AWS, " + "such as not being able to access the network."); System.out.println("Error Message: " + ace.getMessage()); } } public static void main(String[] args) throws Exception { long readCapacity = 5; long writeCapacity = 5; if (args.length > 0) { readCapacity = 5; writeCapacity = 5; } else { readCapacity = Long.valueOf(args[0]); writeCapacity = Long.valueOf(args[1]); } new TableCreator().initializeTable(readCapacity, writeCapacity); } private 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) { try { Thread.sleep(1000 * 20); } catch (Exception e) { } try { DescribeTableRequest request = new DescribeTableRequest().withTableName(tableName); TableDescription tableDescription = dynamoDB.describeTable(request).getTable(); String tableStatus = tableDescription.getTableStatus(); System.out.println(" - current state: " + tableStatus); if (tableStatus.equals(TableStatus.ACTIVE.toString())) return; } catch (AmazonServiceException ase) { if (ase.getErrorCode().equalsIgnoreCase("ResourceNotFoundException") == false) throw ase; } } throw new RuntimeException("Table " + tableName + " never went active"); } private void waitForTableToDelete(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) { try { Thread.sleep(1000 * 20); } catch (Exception e) { } try { DescribeTableRequest request = new DescribeTableRequest().withTableName(tableName); TableDescription tableDescription = dynamoDB.describeTable(request).getTable(); String tableStatus = tableDescription.getTableStatus(); System.out.println(" - current state: " + tableStatus); if (tableStatus.equals(TableStatus.ACTIVE.toString())) return; } catch (AmazonServiceException ase) { if (ase.getErrorCode().equalsIgnoreCase("ResourceNotFoundException") == false) throw ase; } } throw new RuntimeException("Table " + tableName + " never went active"); } }