[4.x] Closeable jdbc pool (helidon-io#8571)

* Add close methods to database client classes
- Extended DbClient with AutoCloseable interface
- Updated copyright
* Small fixes to the contribution to align with copyright and formatting rules

---------

Co-authored-by: bjcoombs <ben.coombs@senapt.co.uk>

Author: tomas-langer

dbclient/dbclient/src/main/java/io/helidon/dbclient/DbClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2019, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,7 +31,7 @@
 /**
  * Helidon database client.
  */
-public interface DbClient {
+public interface DbClient extends AutoCloseable {
 
     /**
      * Qualifier used for mapping using {@link io.helidon.common.mapper.MapperManager#map(Object, Class, Class, String...)}.
@@ -77,6 +77,13 @@ public interface DbClient {
      */
     <C> C unwrap(Class<C> cls);
 
+
+    /**
+     * Closes the DbClient and releases any associated resources.
+     */
+    @Override
+    void close();
+
     /**
      * Create Helidon database client.
      *

dbclient/dbclient/src/main/java/io/helidon/dbclient/DbClientBase.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,4 +39,9 @@ protected DbClientBase(DbClientContext context) {
     public DbClientContext context() {
         return context;
     }
+
+    @Override
+    public void close() {
+        // No-op by default
+    }
 }

dbclient/hikari/src/main/java/io/helidon/dbclient/hikari/HikariConnectionPool.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2023, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,12 +27,13 @@
 import io.helidon.common.config.Config;
 import io.helidon.dbclient.DbClientException;
 import io.helidon.dbclient.hikari.spi.HikariMetricsProvider;
+import io.helidon.dbclient.jdbc.CloseableJdbcConnectionPool;
 import io.helidon.dbclient.jdbc.JdbcConnectionPool;
 
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 
-class HikariConnectionPool implements JdbcConnectionPool {
+class HikariConnectionPool implements CloseableJdbcConnectionPool {
 
     private final HikariDataSource dataSource;
     private final String dbType;
@@ -71,6 +72,11 @@ public Connection connection() {
         }
     }
 
+    @Override
+    public void close() {
+        dataSource.close();
+    }
+
     @Override
     public String dbType() {
         return dbType;

dbclient/jdbc/src/main/java/io/helidon/dbclient/jdbc/CloseableJdbcConnectionPool.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2024 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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.
+ */
+
+package io.helidon.dbclient.jdbc;
+
+/**
+ * CloseableJdbcConnectionPool is an interface that represents a JDBC connection pool that can be closed.
+ * It extends the JdbcConnectionPool interface and the AutoCloseable interface.
+ *
+ * @see JdbcConnectionPool
+ * @see AutoCloseable
+ */
+public interface CloseableJdbcConnectionPool extends JdbcConnectionPool, AutoCloseable {
+}

dbclient/jdbc/src/main/java/io/helidon/dbclient/jdbc/JdbcClient.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2019, 2024 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package io.helidon.dbclient.jdbc;
 
+import java.lang.System.Logger.Level;
 import java.sql.Connection;
 
 import io.helidon.dbclient.DbClient;
@@ -24,6 +25,7 @@
  * Helidon DB implementation for JDBC drivers.
  */
 class JdbcClient extends DbClientBase implements DbClient {
+    private static final System.Logger LOGGER = System.getLogger(JdbcClient.class.getName());
 
     private final JdbcConnectionPool connectionPool;
 
@@ -64,6 +66,17 @@ public JdbcClientContext context() {
         return (JdbcClientContext) super.context();
     }
 
+    @Override
+    public void close() {
+        if (connectionPool instanceof CloseableJdbcConnectionPool cjcp) {
+            try {
+                cjcp.close();
+            } catch (Exception e) {
+                LOGGER.log(Level.WARNING, "Failed to close the connection pool", e);
+            }
+        }
+    }
+
     @Override
     public <C> C unwrap(Class<C> cls) {
         if (Connection.class.isAssignableFrom(cls)) {