change method access modifiers

backend/src/main/java/ch/puzzle/okr/multitenancy/SchemaMultiTenantConnectionProvider.java

@@ -15,6 +15,35 @@
 
 import static ch.puzzle.okr.multitenancy.TenantContext.DEFAULT_TENANT_ID;
 
+/**
+ * The central piece of code of multitenancy.
+ *
+ * <pre>
+ * getConnection(tenantId) sets in each tenant request the specific db schema for the
+ * tenant. This guarantees that each tenant always works in its own DB schema.
+ *
+ * getConnection(tenantId) -> Connection calls in the abstract super class the
+ * getConnection(tenantId) -> Connection which calls the abstract
+ * selectConnectionProvider(tenantIdentifier) -> ConnectionProvider which is implemented
+ * in SchemaMultiTenantConnectionProvider.
+ * </pre>
+ *
+ * <pre>
+ * Some coding details:
+ *
+ * selectConnectionProvider(tenantId) -> ConnectionProvider returns for a tenant a
+ * ConnectionProvider. It first checks if the ConnectionProvider for the tenant is already
+ * cached (in connectionProviderMap). If the ConnectionProvider is cached, it returns it.
+ * Otherwise it creates a ConnectionProvider for the tenant, cache it and return it.
+ *
+ * To create a ConnectionProvider for the tenant, it tries to load the configuration from
+ * the hibernate properties. For this it uses 2 methods of HibernateContext:
+ * getHibernateConfig() if the tenant is the DEFAULT_TENANT_ID (public) and
+ * getHibernateConfig(tenantId) for all other tenants. With this information its then
+ * possible to create and cache a ConnectionProvider for the tenant. If no matching
+ * hibernate properties are found, then an exception is thrown.
+ * </pre>
+ */
 public class SchemaMultiTenantConnectionProvider extends AbstractMultiTenantConnectionProvider<String> {
 
     private static final Logger logger = LoggerFactory.getLogger(SchemaMultiTenantConnectionProvider.class);
@@ -31,15 +60,15 @@ public Connection getConnection(String tenantIdentifier) throws SQLException {
         return getConnection(tenantIdentifier, connection);
     }
 
-    protected Connection getConnection(String tenantIdentifier, Connection connection) throws SQLException {
+    Connection getConnection(String tenantIdentifier, Connection connection) throws SQLException {
         String schema = convertTenantIdToSchemaName(tenantIdentifier);
         logger.debug("Setting schema to {}", schema);
 
         connection.createStatement().execute(String.format("SET SCHEMA '%s';", schema));
         return connection;
     }
 
-    private String convertTenantIdToSchemaName(String tenantIdentifier) {
+    String convertTenantIdToSchemaName(String tenantIdentifier) {
         return Objects.equals(tenantIdentifier, DEFAULT_TENANT_ID) ? tenantIdentifier
                 : MessageFormat.format("okr_{0}", tenantIdentifier);
     }
@@ -54,13 +83,13 @@ protected ConnectionProvider selectConnectionProvider(String tenantIdentifier) {
         return getConnectionProvider(tenantIdentifier);
     }
 
-    protected ConnectionProvider getConnectionProvider(String tenantIdentifier) {
+    ConnectionProvider getConnectionProvider(String tenantIdentifier) {
         return Optional.ofNullable(tenantIdentifier) //
                 .map(connectionProviderMap::get) //
-                .orElseGet(() -> createNewConnectionProvider(tenantIdentifier));
+                .orElseGet(() -> createAndCacheNewConnectionProvider(tenantIdentifier));
     }
 
-    private ConnectionProvider createNewConnectionProvider(String tenantIdentifier) {
+    private ConnectionProvider createAndCacheNewConnectionProvider(String tenantIdentifier) {
         return Optional.ofNullable(tenantIdentifier) //
                 .map(this::createConnectionProvider) //
                 .map(connectionProvider -> {
@@ -78,29 +107,25 @@ private ConnectionProvider createConnectionProvider(String tenantIdentifier) {
                 .orElse(null);
     }
 
-    protected Properties getHibernatePropertiesForTenantIdentifier(String tenantIdentifier) {
+    Properties getHibernatePropertiesForTenantIdentifier(String tenantIdentifier) {
         Properties properties = getHibernateProperties(tenantIdentifier);
         if (properties.isEmpty()) {
-            throw new RuntimeException("Cannot load hibernate properties from application.properties)");
+            throw new RuntimeException("Cannot load hibernate properties from application.properties");
         }
         if (!Objects.equals(tenantIdentifier, DEFAULT_TENANT_ID)) {
             properties.put(AvailableSettings.DEFAULT_SCHEMA, MessageFormat.format("okr_{0}", tenantIdentifier));
         }
         return properties;
     }
 
-    private ConnectionProvider initConnectionProvider(Properties hibernateProperties) {
+    ConnectionProvider initConnectionProvider(Properties hibernateProperties) {
         Map<String, Object> configProperties = convertPropertiesToMap(hibernateProperties);
-        DriverManagerConnectionProviderImpl connectionProvider = getDriverManagerConnectionProviderImpl();
+        DriverManagerConnectionProviderImpl connectionProvider = new DriverManagerConnectionProviderImpl();
         connectionProvider.configure(configProperties);
         return connectionProvider;
     }
 
-    protected DriverManagerConnectionProviderImpl getDriverManagerConnectionProviderImpl() {
-        return new DriverManagerConnectionProviderImpl();
-    }
-
-    private Map<String, Object> convertPropertiesToMap(Properties properties) {
+    Map<String, Object> convertPropertiesToMap(Properties properties) {
         Map<String, Object> configProperties = new HashMap<>();
         for (String key : properties.stringPropertyNames()) {
             String value = properties.getProperty(key);
@@ -109,7 +134,7 @@ private Map<String, Object> convertPropertiesToMap(Properties properties) {
         return configProperties;
     }
 
-    protected Properties getHibernateProperties(String tenantIdentifier) {
+    private Properties getHibernateProperties(String tenantIdentifier) {
         if (tenantIdentifier.equals(DEFAULT_TENANT_ID)) {
             return HibernateContext.getHibernateConfig();
         }