[misc] implement internal Closable

src/main/java/org/mariadb/jdbc/CallableParameterMetaData.java

@@ -147,40 +147,29 @@ int mapMariaDbTypeToJdbc(String str) {
 
 
     private String[] queryMetaInfos(boolean isFunction) throws SQLException {
-        PreparedStatement preparedStatement;
-        if (database != null) {
-            preparedStatement = con.prepareStatement("select param_list, returns, db, type from mysql.proc where db=? and name=?");
-        } else {
-            preparedStatement = con.prepareStatement("select param_list, returns, db, type from mysql.proc where db=DATABASE() and name=?");
-        }
-
-        ResultSet rs = null;
         String paramList;
         String functionReturn;
-        try {
-            if (database == null) {
-                preparedStatement.setString(1, name);
-            } else {
-                preparedStatement.setString(1, database);
-                preparedStatement.setString(2, name);
-            }
-            rs = preparedStatement.executeQuery();
-            if (!rs.next()) {
-                throw new SQLException((isFunction ? "function" : "procedure") + " `" + name + "` does not exist");
+        try (PreparedStatement preparedStatement = con.prepareStatement(
+                "select param_list, returns, db, type from mysql.proc where name=? and db="
+                + (database != null ? "?" : "DATABASE()"))) {
+
+            preparedStatement.setString(1, name);
+            if (database != null) preparedStatement.setString(2, database);
+
+            try (ResultSet rs = preparedStatement.executeQuery()) {
+                if (!rs.next()) {
+                    throw new SQLException((isFunction ? "function" : "procedure") + " `" + name + "` does not exist");
+                }
+                paramList = rs.getString(1);
+                functionReturn = rs.getString(2);
+                database = rs.getString(3);
+                this.isFunction = "FUNCTION".equals(rs.getString(4));
+                return new String[]{paramList, functionReturn};
             }
-            paramList = rs.getString(1);
-            functionReturn = rs.getString(2);
-            database = rs.getString(3);
-            this.isFunction = "FUNCTION".equals(rs.getString(4));
-            return new String[]{paramList, functionReturn};
+
         } catch (SQLSyntaxErrorException sqlSyntaxErrorException) {
             throw new SQLException("Access to metaData informations not granted for current user. Consider grant select access to mysql.proc "
                     + " or avoid using parameter by name", sqlSyntaxErrorException);
-        } finally {
-            if (rs != null) {
-                rs.close();
-            }
-            preparedStatement.close();
         }
 
     }

src/main/java/org/mariadb/jdbc/MariaDbConnection.java

@@ -583,14 +583,10 @@ public boolean getAutoCommit() throws SQLException {
      * @throws SQLException if something goes wrong talking to the server.
      */
     public void setAutoCommit(boolean autoCommit) throws SQLException {
-        if (autoCommit == getAutoCommit()) {
-            return;
-        }
-        Statement stmt = createStatement();
-        try {
+        if (autoCommit == getAutoCommit()) return;
+
+        try (Statement stmt = createStatement()) {
             stmt.executeUpdate("set autocommit=" + ((autoCommit) ? "1" : "0"));
-        } finally {
-            stmt.close();
         }
     }
 
@@ -600,18 +596,17 @@ public void setAutoCommit(boolean autoCommit) throws SQLException {
      * @throws SQLException if there is an error commiting.
      */
     public void commit() throws SQLException {
-        lock.lock();
-        try {
-            if (!getAutoCommit()) {
-                Statement st = createStatement();
-                try {
-                    st.execute("COMMIT");
-                } finally {
-                    st.close();
+        if (!getAutoCommit()) {
+            lock.lock();
+            try {
+                if (!getAutoCommit()) {
+                    try (Statement st = createStatement()) {
+                        st.execute("COMMIT");
+                    }
                 }
+            } finally {
+                lock.unlock();
             }
-        } finally {
-            lock.unlock();
         }
     }
 
@@ -621,11 +616,8 @@ public void commit() throws SQLException {
      * @throws SQLException if there is an error rolling back.
      */
     public void rollback() throws SQLException {
-        Statement st = createStatement();
-        try {
+        try (Statement st = createStatement()) {
             st.execute("ROLLBACK");
-        } finally {
-            st.close();
         }
     }
 
@@ -643,9 +635,9 @@ public void rollback() throws SQLException {
      * @since 1.4
      */
     public void rollback(final Savepoint savepoint) throws SQLException {
-        Statement st = createStatement();
-        st.execute("ROLLBACK TO SAVEPOINT " + savepoint.toString());
-        st.close();
+        try (Statement st = createStatement()) {
+            st.execute("ROLLBACK TO SAVEPOINT " + savepoint.toString());
+        }
     }
 
     /**
@@ -722,19 +714,12 @@ public void setReadOnly(final boolean readOnly) throws SQLException {
      * @see #setCatalog
      */
     public String getCatalog() throws SQLException {
-        String catalog = null;
-        Statement st = null;
-        try {
-            st = createStatement();
-            ResultSet rs = st.executeQuery("select database()");
-            rs.next();
-            catalog = rs.getString(1);
-        } finally {
-            if (st != null) {
-                st.close();
+        try (Statement st = createStatement()) {
+            try (ResultSet rs = st.executeQuery("select database()")) {
+                rs.next();
+                return rs.getString(1);
             }
         }
-        return catalog;
     }
 
     /**
@@ -768,25 +753,23 @@ public void setCatalog(final String catalog) throws SQLException {
      * @see #setTransactionIsolation
      */
     public int getTransactionIsolation() throws SQLException {
-        final Statement stmt = createStatement();
-        try {
-            final ResultSet rs = stmt.executeQuery("SELECT @@tx_isolation");
-            rs.next();
-            final String response = rs.getString(1);
-            if (response.equals("REPEATABLE-READ")) {
-                return Connection.TRANSACTION_REPEATABLE_READ;
-            }
-            if (response.equals("READ-UNCOMMITTED")) {
-                return Connection.TRANSACTION_READ_UNCOMMITTED;
-            }
-            if (response.equals("READ-COMMITTED")) {
-                return Connection.TRANSACTION_READ_COMMITTED;
-            }
-            if (response.equals("SERIALIZABLE")) {
-                return Connection.TRANSACTION_SERIALIZABLE;
+        try (Statement stmt = createStatement()) {
+            try (ResultSet rs = stmt.executeQuery("SELECT @@tx_isolation")) {
+                rs.next();
+                final String response = rs.getString(1);
+                if (response.equals("REPEATABLE-READ")) {
+                    return Connection.TRANSACTION_REPEATABLE_READ;
+                }
+                if (response.equals("READ-UNCOMMITTED")) {
+                    return Connection.TRANSACTION_READ_UNCOMMITTED;
+                }
+                if (response.equals("READ-COMMITTED")) {
+                    return Connection.TRANSACTION_READ_COMMITTED;
+                }
+                if (response.equals("SERIALIZABLE")) {
+                    return Connection.TRANSACTION_SERIALIZABLE;
+                }
             }
-        } finally {
-            stmt.close();
         }
         throw ExceptionMapper.getSqlException("Could not get transaction isolation level");
     }
@@ -825,36 +808,27 @@ public void setTransactionIsolation(final int level) throws SQLException {
      * @see SQLWarning
      */
     public SQLWarning getWarnings() throws SQLException {
-        if (warningsCleared || isClosed() || !protocol.hasWarnings()) {
-            return null;
-        }
-        Statement st = null;
-        ResultSet rs = null;
+        if (warningsCleared || isClosed() || !protocol.hasWarnings()) return null;
+
         SQLWarning last = null;
         SQLWarning first = null;
-        try {
-            st = this.createStatement();
-            rs = st.executeQuery("show warnings");
-            // returned result set has 'level', 'code' and 'message' columns, in this order.
-            while (rs.next()) {
-                int code = rs.getInt(2);
-                String message = rs.getString(3);
-                SQLWarning warning = new SQLWarning(message, ExceptionMapper.mapCodeToSqlState(code), code);
-                if (first == null) {
-                    first = warning;
-                    last = warning;
-                } else {
-                    last.setNextWarning(warning);
-                    last = warning;
+
+        try (Statement st = this.createStatement()) {
+            try (ResultSet rs = st.executeQuery("show warnings")) {
+                // returned result set has 'level', 'code' and 'message' columns, in this order.
+                while (rs.next()) {
+                    int code = rs.getInt(2);
+                    String message = rs.getString(3);
+                    SQLWarning warning = new SQLWarning(message, ExceptionMapper.mapCodeToSqlState(code), code);
+                    if (first == null) {
+                        first = warning;
+                        last = warning;
+                    } else {
+                        last.setNextWarning(warning);
+                        last = warning;
+                    }
                 }
             }
-        } finally {
-            if (rs != null) {
-                rs.close();
-            }
-            if (st != null) {
-                st.close();
-            }
         }
         return first;
     }
@@ -968,8 +942,9 @@ public Savepoint setSavepoint() throws SQLException {
      */
     public Savepoint setSavepoint(final String name) throws SQLException {
         Savepoint savepoint = new MariaDbSavepoint(name, savepointCount++);
-        Statement st = createStatement();
-        st.execute("SAVEPOINT " + savepoint.toString());
+        try (Statement st = createStatement()) {
+            st.execute("SAVEPOINT " + savepoint.toString());
+        }
         return savepoint;
 
     }
@@ -986,9 +961,9 @@ public Savepoint setSavepoint(final String name) throws SQLException {
      * @since 1.4
      */
     public void releaseSavepoint(final Savepoint savepoint) throws SQLException {
-        Statement st = createStatement();
-        st.execute("RELEASE SAVEPOINT " + savepoint.toString());
-        st.close();
+        try (Statement st = createStatement()) {
+            st.execute("RELEASE SAVEPOINT " + savepoint.toString());
+        }
     }
 
     /**
@@ -1405,10 +1380,12 @@ public void setHostFailed() {
      */
     public int getLowercaseTableNames() throws SQLException {
         if (lowercaseTableNames == -1) {
-            Statement st = createStatement();
-            ResultSet rs = st.executeQuery("select @@lower_case_table_names");
-            rs.next();
-            lowercaseTableNames = rs.getInt(1);
+            try (Statement st = createStatement()) {
+                try (ResultSet rs = st.executeQuery("select @@lower_case_table_names")) {
+                    rs.next();
+                    lowercaseTableNames = rs.getInt(1);
+                }
+            }
         }
         return lowercaseTableNames;
     }
@@ -1420,9 +1397,8 @@ public int getLowercaseTableNames() throws SQLException {
      * @throws SQLException if security manager doesn't permit it.
      */
     public void abort(Executor executor) throws SQLException {
-        if (this.isClosed()) {
-            return;
-        }
+        if (this.isClosed()) return;
+
         SQLPermission sqlPermission = new SQLPermission("callAbort");
         SecurityManager securityManager = System.getSecurityManager();
         if (securityManager != null && sqlPermission != null) {
@@ -1431,6 +1407,7 @@ public void abort(Executor executor) throws SQLException {
         if (executor == null) {
             throw ExceptionMapper.getSqlException("Cannot abort the connection: null executor passed");
         }
+
         executor.execute(new Runnable() {
             @Override
             public void run() {

src/main/java/org/mariadb/jdbc/internal/packet/send/gssapi/StandardGssapiAuthentication.java

@@ -80,16 +80,16 @@ public void authenticate(final PacketOutputStream writer, final String serverPri
             final File jaasConfFile;
             try {
                 jaasConfFile = File.createTempFile("jaas.conf", null);
-                final PrintStream bos = new PrintStream(new FileOutputStream(jaasConfFile));
-                bos.print(String.format(
-                        "Krb5ConnectorContext {\n"
-                                + "com.sun.security.auth.module.Krb5LoginModule required "
-                                + "useTicketCache=true "
-                                + "debug=true "
-                                + "renewTGT=true "
-                                + "doNotPrompt=true; };"
-                ));
-                bos.close();
+                try (PrintStream bos = new PrintStream(new FileOutputStream(jaasConfFile))) {
+                    bos.print(String.format(
+                            "Krb5ConnectorContext {\n"
+                                    + "com.sun.security.auth.module.Krb5LoginModule required "
+                                    + "useTicketCache=true "
+                                    + "debug=true "
+                                    + "renewTGT=true "
+                                    + "doNotPrompt=true; };"
+                    ));
+                }
                 jaasConfFile.deleteOnExit();
             } catch (final IOException ex) {
                 throw new IOError(ex);

src/main/java/org/mariadb/jdbc/internal/protocol/AbstractQueryProtocol.java

@@ -730,12 +730,12 @@ public void setCatalog(final String database) throws QueryException {
      */
     @Override
     public void cancelCurrentQuery() throws QueryException, IOException {
-        MasterProtocol copiedProtocol = new MasterProtocol(urlParser, new ReentrantLock());
-        copiedProtocol.setHostAddress(getHostAddress());
-        copiedProtocol.connect();
-        //no lock, because there is already a query running that possessed the lock.
-        copiedProtocol.executeQuery("KILL QUERY " + serverThreadId);
-        copiedProtocol.close();
+        try (MasterProtocol copiedProtocol = new MasterProtocol(urlParser, new ReentrantLock())) {
+            copiedProtocol.setHostAddress(getHostAddress());
+            copiedProtocol.connect();
+            //no lock, because there is already a query running that possessed the lock.
+            copiedProtocol.executeQuery("KILL QUERY " + serverThreadId);
+        }
     }
 
     @Override

src/main/java/org/mariadb/jdbc/internal/protocol/MasterProtocol.java

@@ -57,12 +57,13 @@ WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWIS
 import org.mariadb.jdbc.internal.failover.Listener;
 import org.mariadb.jdbc.internal.failover.tools.SearchFilter;
 
+import java.io.Closeable;
 import java.util.ArrayDeque;
 import java.util.List;
 import java.util.concurrent.locks.ReentrantLock;
 
 
-public class MasterProtocol extends AbstractQueryProtocol {
+public class MasterProtocol extends AbstractQueryProtocol implements Closeable {
 
     /**
      * Get a protocol instance.

src/test/java/org/mariadb/jdbc/AllowMultiQueriesTest.java

@@ -119,7 +119,6 @@ public void allowMultiQueriesFetchInsertSelectTest() throws SQLException {
             try (Statement statement = connection.createStatement()) {
                 statement.setFetchSize(1);
                 statement.execute("INSERT INTO AllowMultiQueriesTest2(test) VALUES ('a'), ('b');SELECT * from AllowMultiQueriesTest;SELECT 3;");
-                statement.close();
             }
         }
     }