sql refactoring

db/src/main/java/org/zhdev/sql/H2SqlConnection.java

@@ -1,9 +0,0 @@
-package org.zhdev.sql;
-
-import org.zhdev.util.SqlUtils;
-
-public final class H2SqlConnection extends AbstractSqlConnection {
-    public H2SqlConnection(String path, String username, String password) {
-        super(SqlUtils.createH2Connection(path, username, password));
-    }
-}

db/src/main/java/org/zhdev/sql/MySqlConnection.java

@@ -1,9 +0,0 @@
-package org.zhdev.sql;
-
-import org.zhdev.util.SqlUtils;
-
-public final class MySqlConnection extends AbstractSqlConnection {
-    public MySqlConnection(String address, String dbname, String username, String password, boolean ssl) {
-        super(SqlUtils.createMySqlConnection(address, dbname, username, password, ssl));
-    }
-}

db/src/main/java/org/zhdev/sql/SqlAdapter.java

@@ -1,51 +0,0 @@
-package org.zhdev.sql;
-
-import org.zhdev.util.CheckedFunction;
-
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.util.Objects;
-
-public final class SqlAdapter implements AutoCloseable {
-    private SqlConnection connection = SqlConnection.NOT_ESTABLISHED;
-
-    public SqlConnection getConnection() {
-        return connection;
-    }
-
-    public void setConnection(SqlConnection connection) {
-        Objects.requireNonNull(connection, "connection");
-        this.connection = connection;
-    }
-
-    public <T> T prepareStatement(CheckedFunction<PreparedStatement, T, SQLException> function, String query, Object... args) throws SqlException {
-        try (PreparedStatement statement = connection.prepareStatement(query)) {
-            for (int i = 0, j = 1; i < args.length; i++, j++) {
-                statement.setObject(j, args[i]);
-            }
-            return function.apply(statement);
-        } catch (SQLException e) {
-            throw new SqlException(e);
-        }
-    }
-
-    public <T> T executeQuery(CheckedFunction<ResultSet, T, SQLException> function, String query, Object... args) throws SqlException {
-        return prepareStatement(statement -> {
-            try (ResultSet set = statement.executeQuery()) {
-                return function.apply(set);
-            }
-        }, query, args);
-    }
-
-    public boolean isClosed() {
-        return connection.isClosed();
-    }
-
-    public void close() {
-        if (connection.isClosed()) {
-            connection.close();
-        }
-        connection = SqlConnection.CLOSED;
-    }
-}

db/src/main/java/org/zhdev/sql/SqlConnection.java

@@ -1,46 +0,0 @@
-package org.zhdev.sql;
-
-import java.sql.PreparedStatement;
-import java.sql.SQLException;
-
-public interface SqlConnection extends AutoCloseable {
-    SqlConnection NOT_ESTABLISHED = new SqlConnection() {
-        @Override
-        public PreparedStatement prepareStatement(String query) {
-            throw new SqlException("Connection not established");
-        }
-
-        @Override
-        public boolean isClosed() {
-            return true;
-        }
-
-        @Override
-        public void close() {
-            throw new SqlException("Connection not established");
-        }
-    };
-    SqlConnection CLOSED = new SqlConnection() {
-        @Override
-        public PreparedStatement prepareStatement(String query) {
-            throw new SqlException("Connection closed");
-        }
-
-        @Override
-        public boolean isClosed() {
-            return true;
-        }
-
-        @Override
-        public void close() {
-            throw new SqlException("Connection closed");
-        }
-    };
-
-    PreparedStatement prepareStatement(String query) throws SQLException;
-
-    boolean isClosed();
-
-    @Override
-    void close();
-}

db/src/main/java/org/zhdev/sql/SqliteConnection.java

@@ -1,9 +0,0 @@
-package org.zhdev.sql;
-
-import org.zhdev.util.SqlUtils;
-
-public class SqliteConnection extends AbstractSqlConnection {
-    public SqliteConnection(String path) {
-        super(SqlUtils.createSqliteConnection(path));
-    }
-}

db/src/main/java/org/zhdev/varioutil/sql/AbstractProvider.java

@@ -0,0 +1,26 @@
+package org.zhdev.varioutil.sql;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+
+abstract class AbstractProvider implements ConnectionProvider {
+    private final Connection connection;
+
+    AbstractProvider(Connection connection) {
+        this.connection = connection;
+    }
+
+    @Override
+    public Connection getConnection() {
+        return connection;
+    }
+
+    @Override
+    public boolean isClosed() {
+        try {
+            return connection.isClosed();
+        } catch (SQLException e) {
+            throw new SqlException(e);
+        }
+    }
+}

db/src/main/java/org/zhdev/varioutil/sql/H2Provider.java

@@ -0,0 +1,9 @@
+package org.zhdev.varioutil.sql;
+
+import org.zhdev.varioutil.util.SqlUtils;
+
+public class H2Provider extends AbstractProvider {
+    public H2Provider(String path, String username, String password) {
+        super(SqlUtils.createH2Connection(path, username, password));
+    }
+}

db/src/main/java/org/zhdev/varioutil/sql/MysqlProvider.java

@@ -0,0 +1,9 @@
+package org.zhdev.varioutil.sql;
+
+import org.zhdev.varioutil.util.SqlUtils;
+
+public class MysqlProvider extends AbstractProvider {
+    public MysqlProvider(String address, String dbname, String username, String password, boolean ssl) {
+        super(SqlUtils.createMysqlConnection(address, dbname, username, password, ssl));
+    }
+}

db/src/main/java/org/zhdev/varioutil/sql/NullProvider.java

@@ -0,0 +1,17 @@
+package org.zhdev.varioutil.sql;
+
+import java.sql.Connection;
+
+class NullProvider implements ConnectionProvider {
+    private final String message;
+
+    NullProvider(String message) {
+        this.message = message;
+    }
+
+
+    @Override
+    public Connection getConnection() {
+        throw new SqlException(message);
+    }
+}

db/src/main/java/org/zhdev/varioutil/sql/SqlAdapter.java

@@ -0,0 +1,64 @@
+package org.zhdev.varioutil.sql;
+
+import org.zhdev.varioutil.util.CheckedFunction;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.Objects;
+
+public final class SqlAdapter implements AutoCloseable {
+    private ConnectionProvider provider = ConnectionProvider.NOT_ESTABLISHED;
+
+    public void setProvider(ConnectionProvider provider) {
+        Objects.requireNonNull(provider, "provider");
+        this.provider = provider;
+    }
+
+    private static void applyArgs(PreparedStatement statement, Object[] args) throws SQLException {
+        for (int i = 0, j = 1; i < args.length; i++, j++) {
+            statement.setObject(j, args[i]);
+        }
+    }
+
+    public <T> T prepareStatement(CheckedFunction<PreparedStatement, T, SQLException> function, String query, Object... args) throws SqlException {
+        try (PreparedStatement statement = provider.getConnection().prepareStatement(query)) {
+            applyArgs(statement, args);
+            return function.apply(statement);
+        } catch (SQLException e) {
+            throw new SqlException(e);
+        }
+    }
+
+    public <T> T prepareStatement(int autoGeneratedKeys, CheckedFunction<PreparedStatement, T, SQLException> function, String query, Object... args) throws SqlException {
+        try (PreparedStatement statement = provider.getConnection().prepareStatement(query, autoGeneratedKeys)) {
+            applyArgs(statement, args);
+            return function.apply(statement);
+        } catch (SQLException e) {
+            throw new SqlException(e);
+        }
+    }
+
+    public <T> T executeQuery(CheckedFunction<ResultSet, T, SQLException> function, String query, Object... args) throws SqlException {
+        return prepareStatement(statement -> {
+            try (ResultSet set = statement.executeQuery()) {
+                return function.apply(set);
+            }
+        }, query, args);
+    }
+
+
+
+    public boolean isClosed() {
+        return provider.isClosed();
+    }
+
+    public void close() {
+        if (!provider.isClosed()) {
+            provider.close();
+        }
+        provider = ConnectionProvider.CLOSED;
+    }
+
+}

db/src/main/java/org/zhdev/varioutil/sql/SqlException.java

@@ -1,4 +1,4 @@
-package org.zhdev.sql;
+package org.zhdev.varioutil.sql;
 
 public class SqlException extends RuntimeException {
     public SqlException() {

db/src/main/java/org/zhdev/varioutil/sql/SqliteProvider.java

@@ -0,0 +1,9 @@
+package org.zhdev.varioutil.sql;
+
+import org.zhdev.varioutil.util.SqlUtils;
+
+public class SqliteProvider extends AbstractProvider {
+    public SqliteProvider(String path) {
+        super(SqlUtils.createSqliteConnection(path));
+    }
+}

db/src/main/java/org/zhdev/varioutil/util/SqlUtils.java

@@ -1,35 +1,34 @@
-package org.zhdev.util;
+package org.zhdev.varioutil.util;
 
-import org.zhdev.sql.SqlException;
+import org.zhdev.varioutil.sql.SqlException;
 
-import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.sql.*;
 
 public class SqlUtils {
     public static final char[] ESCAPE_CHARS = {'%', '_', '[', ']', '^'};
 
-    public static Connection createMySqlConnection(String address, String dbname, String username, String password, boolean ssl) throws SqlException {
+    private static boolean sqlite;
+    private static boolean h2;
+    private static boolean mysql;
+
+    public static Connection createMysqlConnection(String address, String dbname, String username, String password, boolean ssl) throws SqlException {
         try {
-            try {
-                Class.forName("com.mysql.cj.jdbc.Driver");
-            } catch (ClassNotFoundException e) {
-                Class.forName("com.mysql.jdbc.Driver");
-            }
             if (!address.contains(":")) {
                 address = address + ":3306";
             }
             return DriverManager.getConnection("jdbc:mysql://" + address + '/' + dbname + "?useSSL=" + ssl, username, password);
         } catch (SQLException e) {
             throw new SqlException(e);
-        } catch (ClassNotFoundException e) {
-            throw new SqlException("No suitable driver");
         }
     }
 
     public static Connection createH2Connection(String path, String username, String password) throws SqlException {
         try {
-            Class.forName("org.h2.Driver");
+            DriverManager.registerDriver(new org.h2.Driver());
             Connection connection;
             if (username != null) {
                 connection = DriverManager.getConnection("jdbc:h2:./" + path + ";mode=MySQL;AUTO_SERVER=TRUE", username, password);
@@ -37,29 +36,29 @@ public class SqlUtils {
                 connection = DriverManager.getConnection("jdbc:h2:./" + path + ";mode=MySQL;AUTO_SERVER=TRUE", "sa", "");
             }
             return connection;
-        } catch (ClassNotFoundException e) {
+        } catch (NoClassDefFoundError e) {
             throw new SqlException("No suitable driver");
         } catch (SQLException e) {
             throw new SqlException(e);
         }
     }
 
-    public static Connection createSqliteConnection(String path) throws SqlException {
+    public static Connection createSqliteConnection(String pathname) throws SqlException {
-        File file = new File(path);
+        Path path = Paths.get(pathname);
-        if (!file.exists()) {
+        if (!Files.exists(path)) {
-            File parent = file.getParentFile();
+            Path parent = path.getParent();
-            if (parent != null) {
-                parent.mkdirs();
-            }
             try {
-                file.createNewFile();
+                if (parent != null) {
+                    Files.createDirectories(parent);
+                }
+                Files.createFile(path);
             } catch (IOException e) {
                 throw new SqlException(e);
             }
         }
         try {
             Class.forName("org.sqlite.JDBC");
-            return DriverManager.getConnection("jdbc:sqlite:" + file);
+            return DriverManager.getConnection("jdbc:sqlite:" + path);
         } catch (ClassNotFoundException e) {
             throw new SqlException("No suitable driver");
         } catch (SQLException e) {
@@ -101,4 +100,49 @@ public class SqlUtils {
     public static String unescape(String str, String escape) {
         return StringUtils.unescape(str, escape, ESCAPE_CHARS);
     }
+
+    private static void initializeH2() {
+        if (h2) {
+            return;
+        }
+
+        try {
+            DriverManager.registerDriver(new org.h2.Driver());
+        } catch (NoClassDefFoundError | SQLException ignored) {}
+
+        h2 = true;
+    }
+
+    private static void initializeMySql() {
+        if (mysql) {
+            return;
+        }
+
+        try {
+            try {
+                DriverManager.registerDriver(new com.mysql.cj.jdbc.Driver());
+            } catch (NoClassDefFoundError e) {
+                DriverManager.registerDriver(new com.mysql.jdbc.Driver());
+            }
+        } catch (NoClassDefFoundError | SQLException ignored) {}
+
+        mysql = true;
+    }
+
+    private static void initializeSqlite() {
+        if (sqlite) {
+            return;
+        }
+
+        try {
+            DriverManager.registerDriver(new org.sqlite.JDBC());
+        } catch (NoClassDefFoundError | SQLException ignored) {}
+
+        sqlite = true;
+    }
+
+    static {
+        initializeH2();
+        initializeMySql();
+    }
 }