DynamoDB sample

Bookmark.java

package entity;

import com.amazonaws.services.dynamodb.datamodeling.DynamoDBAttribute;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBAutoGeneratedKey;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBHashKey;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBRangeKey;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBTable;

@DynamoDBTable(tableName = "shortingUrl")
public class Bookmark {
	
	private String shortingUrlKey;
	
	private String redirectUrl;

	@DynamoDBHashKey
	public String getShortingUrlKey() {
		return shortingUrlKey;
	}

	public void setShortingUrlKey(String shortingUrlKey) {
		this.shortingUrlKey = shortingUrlKey;
	}

	@DynamoDBRangeKey
	public String getRedirectUrl() {
		return redirectUrl;
	}

	public void setRedirectUrl(String redirectUrl) {
		this.redirectUrl = redirectUrl;
	}

}

DynamoDBManager.java

package dynamo;

import java.util.ArrayList;
import java.util.List;

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.PropertiesCredentials;
import com.amazonaws.services.dynamodb.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBMapper;
import com.amazonaws.services.dynamodb.datamodeling.DynamoDBQueryExpression;
import com.amazonaws.services.dynamodb.datamodeling.PaginatedList;
import com.amazonaws.services.dynamodb.model.ListTablesResult;

public class DynamoDBManager {
	
    static AmazonDynamoDBClient dynamoDB;

    public static void init() throws Exception {
        AWSCredentials credentials = new PropertiesCredentials(
                AmazonDynamoDBSample.class.getResourceAsStream("AwsCredentials.properties"));

        dynamoDB = new AmazonDynamoDBClient(credentials);
        dynamoDB.setEndpoint("https://dynamodb.ap-northeast-1.amazonaws.com");
    }

    public static void save(Object entity) {
        DynamoDBMapper mapper = new DynamoDBMapper(dynamoDB);
        mapper.save(entity);
    }
    
    public static <T> PaginatedList<T> query(Class<T> klass, DynamoDBQueryExpression query) {
        DynamoDBMapper mapper = new DynamoDBMapper(dynamoDB);
        PaginatedList<T> list = mapper.query(klass, query);
        return list;
    }

    public static <T> T get(Class<T> klass, DynamoDBQueryExpression query) {
        DynamoDBMapper mapper = new DynamoDBMapper(dynamoDB);
        PaginatedList<T> list = mapper.query(klass, query);
        if (list.isEmpty()) {
        	return null;
        }
        return list.get(0);
    }

    public static List<String> tableNames() {
    	ListTablesResult tables = dynamoDB.listTables();
    	List<String> result = new ArrayList<String>();
    	for (String tableName : tables.getTableNames()) {
    		result.add(tableName);
    	}
    	return result;
    }
    
}

SaveAndGet.java

package dynamo;

import com.amazonaws.services.dynamodb.datamodeling.DynamoDBQueryExpression;
import com.amazonaws.services.dynamodb.datamodeling.PaginatedList;
import com.amazonaws.services.dynamodb.model.AttributeValue;

import entity.Bookmark;

public class SaveAndGet {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		if (args.length != 2) {
			System.out.println("usage: shortkey url");
			return;
		}
		
		DynamoDBManager.init();
		Bookmark bookmark = new Bookmark();
		
		String key = args[0];
		bookmark.setShortingUrlKey(key);
		bookmark.setRedirectUrl(args[1]);

		DynamoDBManager.save(bookmark);
		
		AttributeValue value = new AttributeValue(key);
		DynamoDBQueryExpression query = new DynamoDBQueryExpression(value);
		Bookmark result = DynamoDBManager.get(Bookmark.class, query);
		
		System.out.printf("%s = %s\n", result.getShortingUrlKey(), result.getRedirectUrl());
	}

}