add support for multiple databases; breaking configuration changes

README.md

@@ -5,7 +5,15 @@ Caffeine ORM is a wrapper used to handle the lower level database connections an
 
 #### Initialization
 ```
-CaffeineConnection.setConfiguration(driver (example: "org.postgresql.Driver"), url, username, password));
+CaffeineConnection.addDatabase(name of database, driver (example: "org.postgresql.Driver"), url, username, password));
+CaffeineConnection.useDatabase(name of database to use);
+```
+
+Multiple databases are supported for larger applications. The credentials for the database to use is stored in the CaffeineConnection class and can be switched on a per-query basis. If you have a single database application, you merely need to set once and forget.
+```
+CaffeineConnection.addDatabase("secondary", driver, url, username, password);
+CaffeineConnection.addDatabase("tertiary", driver, url, username, password);
+CaffeineConnection.useDatabase("tertiary");
 ```
 
 #### Usage

src/supahnickie/caffeine/CaffeineConnection.java

@@ -7,6 +7,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 public final class CaffeineConnection {
 	@SuppressWarnings("rawtypes")
@@ -16,12 +17,26 @@ public final class CaffeineConnection {
 	private static String dbUsername;
 	private static String dbPassword;
 	private static Connection connection;
+	private static Map<String, String[]> connectionCredentials = new HashMap<String, String[]>();
 
-	public static final void setConfiguration(String driver, String url, String username, String password) {
-		dbDriver = driver;
-		dbUrl = url;
-		dbUsername = username;
-		dbPassword = password;
+	public static final Set<String> listDatabases() {
+		return connectionCredentials.keySet();
+	}
+
+	public static final void useDatabase(String name) throws Exception {
+		if ( !(connectionCredentials.containsKey(name)) ) {
+			throw new Exception("database " + name + " has not been added to the list of databases yet; use the 'addDatabaseConnection' method");
+		}
+		String[] creds = connectionCredentials.get(name);
+		dbDriver = creds[0];
+		dbUrl = creds[1];
+		dbUsername = creds[2];
+		dbPassword = creds[3];
+	}
+
+	public static final void addDatabaseConnection(String name, String driver, String url, String username, String password) {
+		String[] creds = new String[] { driver, url, username, password };
+		connectionCredentials.put(name, creds);
 	}
 
 	static final Connection setup() {

src/supahnickie/caffeineTester/CaffeineTest.java

@@ -13,6 +13,29 @@
 
 public class CaffeineTest {
 
+	@Test
+	public void multipleDatabaseConnections() throws Exception {
+		CaffeineConnection.useDatabase("primary");
+		CaffeineObject.setQueryClass(User.class);
+		List<CaffeineObject> primaryDbUsers = CaffeineConnection.objectQuery("select * from users");
+		User user1 = (User) primaryDbUsers.get(0);
+		User user2 = (User) primaryDbUsers.get(1);
+		User user3 = (User) primaryDbUsers.get(2);
+		CaffeineConnection.useDatabase("secondary");
+		List<CaffeineObject> secondaryDbUsers = CaffeineConnection.objectQuery("select * from users");
+		User user4 = (User) secondaryDbUsers.get(0);
+		User user5 = (User) secondaryDbUsers.get(1);
+		User user6 = (User) secondaryDbUsers.get(2);
+		CaffeineConnection.useDatabase("tertiary");
+		List<CaffeineObject> tertiaryDbUsers = CaffeineConnection.objectQuery("select * from users");
+		User user7 = (User) tertiaryDbUsers.get(0);
+		User user8 = (User) tertiaryDbUsers.get(1);
+		User user9 = (User) tertiaryDbUsers.get(2);
+		assertArrayEquals("first names from first database should match expected", new String[] { "Grawr", "Nick", "Test" }, new String[] { user1.getFirstName(), user2.getFirstName(), user3.getFirstName() });
+		assertArrayEquals("first names from second database should match expected", new String[] { "Saint", "Easter", "Freddy" }, new String[] { user4.getFirstName(), user5.getFirstName(), user6.getFirstName() });
+		assertArrayEquals("first names from third database should match expected", new String[] { "Oliver", "Thomas", "Tiger" }, new String[] { user7.getFirstName(), user8.getFirstName(), user9.getFirstName() });
+	}
+
 	@Test
 	public void rawQueryRawData() throws Exception {
 		List<HashMap<String, Object>> rawReturn = CaffeineConnection.rawQuery("select downloads.*, users.* from downloads join users on downloads.user_id = users.id where downloads.id in (1, 2, 3) order by downloads.id asc");
@@ -733,19 +756,24 @@ public void updateValidations() throws Exception {
 	@Before
 	public void setUp() throws Exception {
 		// The database must already exist, but should be blank otherwise.
-		CaffeineConnection.setConfiguration(System.getenv("CAFFEINE_DB_DRIVER"), System.getenv("CAFFEINE_DB_TEST_URL"), System.getenv("CAFFEINE_DB_USERNAME"), System.getenv("CAFFEINE_DB_PASSWORD"));
+		CaffeineConnection.addDatabaseConnection("primary", System.getenv("CAFFEINE_DB_DRIVER"), System.getenv("CAFFEINE_DB_TEST_URL"), System.getenv("CAFFEINE_DB_USER"), System.getenv("CAFFEINE_DB_PASSWORD"));
+		CaffeineConnection.addDatabaseConnection("secondary", System.getenv("CAFFEINE_DB_DRIVER"), System.getenv("CAFFEINE_DB_TEST_URL_2"), System.getenv("CAFFEINE_DB_USER"), System.getenv("CAFFEINE_DB_PASSWORD"));
+		CaffeineConnection.addDatabaseConnection("tertiary", System.getenv("CAFFEINE_DB_DRIVER"), System.getenv("CAFFEINE_DB_TEST_URL_3"), System.getenv("CAFFEINE_DB_USER"), System.getenv("CAFFEINE_DB_PASSWORD"));
 		insertTables();
 		insertUsers();
 		insertDownloads();
+		CaffeineConnection.useDatabase("primary");
 	}
 
 	@After
 	public void tearDown() throws Exception {
+		CaffeineConnection.useDatabase("primary");
 		CaffeineConnection.rawUpdate("drop table if exists users");
 		CaffeineConnection.rawUpdate("drop table if exists downloads");
 	}
 
 	public void insertTables() throws Exception {
+		CaffeineConnection.useDatabase("primary");
 		CaffeineConnection.rawUpdate("drop table if exists users");
 		CaffeineConnection.rawUpdate("drop table if exists downloads");
 		CaffeineConnection.rawUpdate("create table if not exists users (" +
@@ -762,17 +790,51 @@ public void insertTables() throws Exception {
 			"org_id integer, " +
 			"user_id integer)"
 		);
+		CaffeineConnection.useDatabase("secondary");
+		CaffeineConnection.rawUpdate("drop table if exists users");
+		CaffeineConnection.rawUpdate("create table if not exists users (" +
+			"id serial primary key, " +
+			"first_name varchar(255), " +
+			"last_name varchar(255), " +
+			"encrypted_password varchar(255), " +
+			"sign_in_count integer, " +
+			"role varchar(255))"
+		);
+		CaffeineConnection.useDatabase("tertiary");
+		CaffeineConnection.rawUpdate("drop table if exists users");
+		CaffeineConnection.rawUpdate("create table if not exists users (" +
+			"id serial primary key, " +
+			"first_name varchar(255), " +
+			"last_name varchar(255), " +
+			"encrypted_password varchar(255), " +
+			"sign_in_count integer, " +
+			"role varchar(255))"
+		);
 	}
 
 	private void insertUsers() throws Exception {
+		CaffeineConnection.useDatabase("primary");
 		CaffeineConnection.rawUpdate("insert into users (first_name, last_name, encrypted_password, sign_in_count, role) values " +
 			"('Grawr', 'McPhee', 'qwerqwer', 13, 'admin')," +
 			"('Nick', 'Case', 'asdfasdf', 0, 'super')," +
 			"('Test', 'User', 'zxcvzxcv', 3, 'moderator')"
 		);
+		CaffeineConnection.useDatabase("secondary");
+		CaffeineConnection.rawUpdate("insert into users (first_name, last_name, encrypted_password, sign_in_count, role) values " +
+			"('Saint', 'Nicholas', 'opueritpu', 24, 'admin')," +
+			"('Easter', 'Bunny', 'ivobhasd', 4, 'moderator')," +
+			"('Freddy', 'Krueger', '0392ujv', 1, 'normal')"
+		);
+		CaffeineConnection.useDatabase("tertiary");
+		CaffeineConnection.rawUpdate("insert into users (first_name, last_name, encrypted_password, sign_in_count, role) values " +
+			"('Oliver', 'Cromwell', 'v0fd8h', 99, 'super')," +
+			"('Thomas', 'Jefferson', 'as632zz', 357, 'super')," +
+			"('Tiger', 'McLion', 'zxcvzxcv', 67, 'moderator')"
+		);
 	}
 
 	private void insertDownloads() throws Exception {
+		CaffeineConnection.useDatabase("primary");
 		CaffeineConnection.rawUpdate("insert into downloads (file_file_name, org_id, user_id) values " +
 			"('FileTest num 1', 2, 2)," +
 			"('FileTest num 2', 1, 3)," +