Create a Data Access Object for IBM Cloud Object Storage Data using JDBI

JDBI is a SQL convenience library for Java that exposes two different style APIs, a fluent style and a SQL object style. The CData JDBC Driver for IBM Cloud Object Storage integrates connectivity to live IBM Cloud Object Storage data in Java applications. By pairing these technologies, you gain simple, programmatic access to IBM Cloud Object Storage data. This article explains how to build a basic Data Access Object (DAO) and the accompanying code to read IBM Cloud Object Storage data.

Create a DAO for the IBM Cloud Object Storage Objects Entity

The interface below declares the desired behavior for the SQL object to create a single method for each SQL statement to be implemented.

public interface MyObjectsDAO {
 //request specific data from IBM Cloud Object Storage (String type is used for simplicity)
 @SqlQuery("SELECT Etag FROM Objects WHERE Bucket = :bucket")
 String findEtagByBucket(@Bind("bucket") String bucket);

 /*
 * close with no args is used to close the connection
 */
 void close();
}

Open a Connection to IBM Cloud Object Storage

Collect the necessary connection properties and construct the appropriate JDBC URL for connecting to IBM Cloud Object Storage.

Register a New Instance of Cloud Object Storage

If you do not already have Cloud Object Storage in your IBM Cloud account, follow the procedure below to install an instance of SQL Query in your account:

1. Log in to your IBM Cloud account.
2. Navigate to the

Connecting using OAuth Authentication

There are certain connection properties you need to set before you can connect. You can obtain these as follows:

API Key

To connect with IBM Cloud Object Storage, you need an API Key. You can obtain this as follows:

1. Log in to your IBM Cloud account.
2. Navigate to the Platform API Keys page.
3. On the middle-right corner click "Create an IBM Cloud API Key" to create a new API Key.
4. In the pop-up window, specify the API Key name and click "Create". Note the API Key as you can never access it again from the dashboard.

Cloud Object Storage CRN

If you have multiple accounts, specify the CloudObjectStorageCRN explicitly. To find the appropriate value, you can:

• Query the Services view. This will list your IBM Cloud Object Storage instances along with the CRN for each.
• Locate the CRN directly in IBM Cloud. To do so, navigate to your IBM Cloud Dashboard. In the Resource List, Under Storage, select your Cloud Object Storage resource to get its CRN.

Connecting to Data

You can now set the following to connect to data:

• InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
• ApiKey: Set this to your API key which was noted during setup.
• CloudObjectStorageCRN (Optional): Set this to the cloud object storage CRN you want to work with. While the connector attempts to retrieve this automatically, specifying this explicitly is recommended if you have more than Cloud Object Storage account.

When you connect, the connector completes the OAuth process.

1. Extracts the access token and authenticates requests.
2. Saves OAuth values in OAuthSettingsLocation to be persisted across connections.

Built-in Connection String Designer

For assistance in constructing the JDBC URL, use the connection string designer built into the IBM Cloud Object Storage JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

java -jar cdata.jdbc.ibmcloudobjectstorage.jar

Fill in the connection properties and copy the connection string to the clipboard.

👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)

A connection string for IBM Cloud Object Storage will typically look like the following:

jdbc:ibmcloudobjectstorage:ApiKey=myApiKey;CloudObjectStorageCRN=MyInstanceCRN;Region=myRegion;OAuthClientId=MyOAuthClientId;OAuthClientSecret=myOAuthClientSecret;

Use the configured JDBC URL to obtain an instance of the DAO interface. The particular method shown below will open a handle bound to the instance, so the instance needs to be closed explicitly to release the handle and the bound JDBC connection.

DBI dbi = new DBI("jdbc:ibmcloudobjectstorage:ApiKey=myApiKey;CloudObjectStorageCRN=MyInstanceCRN;Region=myRegion;OAuthClientId=MyOAuthClientId;OAuthClientSecret=myOAuthClientSecret;");
MyObjectsDAO dao = dbi.open(MyObjectsDAO.class);

//do stuff with the DAO

dao.close();

Read IBM Cloud Object Storage Data

With the connection open to IBM Cloud Object Storage, simply call the previously defined method to retrieve data from the Objects entity in IBM Cloud Object Storage.

//disply the result of our 'find' method
String etag = dao.findEtagByBucket("someBucket");
System.out.println(etag);

Since the JDBI library is able to work with JDBC connections, you can easily produce a SQL Object API for IBM Cloud Object Storage by integrating with the CData JDBC Driver for IBM Cloud Object Storage. Download a free trial and work with live IBM Cloud Object Storage data in custom Java applications today.