first commit

src/main/java/ru/di9/jdbc/AbstractEntity.java

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+package ru.di9.jdbc;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class AbstractEntity<T> {
+
+    protected T id;
+}

src/main/java/ru/di9/jdbc/DataAccessException.java

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+package ru.di9.jdbc;
+
+import lombok.Getter;
+
+@Getter
+public class DataAccessException extends RuntimeException {
+
+    @SuppressWarnings("java:S1165")
+    private String sql;
+
+    public DataAccessException(String msg, Throwable cause) {
+        super(msg, cause);
+    }
+
+    public DataAccessException(String msg, String sql, Throwable cause) {
+        this(msg + " | " + sql, cause);
+        this.sql = sql;
+    }
+}

src/main/java/ru/di9/jdbc/JdbcTemplate.java

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+package ru.di9.jdbc;
+
+import org.intellij.lang.annotations.Language;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public interface JdbcTemplate {
+
+    void execute(@Language("GenericSQL") String sql) throws DataAccessException;
+
+    void execute(@Language("GenericSQL") String sql, PreparedStatementProcessor psp) throws DataAccessException;
+
+    <T> T query(@Language("GenericSQL") String sql, ResultSetExtractor<T> rse) throws DataAccessException;
+
+    <T> T query(@Language("GenericSQL") String sql, PreparedStatementProcessor psp, ResultSetExtractor<T> rse)
+            throws DataAccessException;
+
+    <T> Optional<T> queryOne(@Language("GenericSQL") String sql, ResultSetExtractor<T> rse)
+            throws DataAccessException;
+
+    <T> Optional<T> queryOne(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                             ResultSetExtractor<T> rse) throws DataAccessException;
+
+    <T> List<T> queryList(@Language("GenericSQL") String sql,
+                          final RowMapper<T> rowMapper) throws DataAccessException;
+
+    <T> List<T> queryList(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                          final RowMapper<T> rowMapper) throws DataAccessException;
+
+    <T> T insert(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                 ResultSetExtractor<T> processGeneratedKey) throws DataAccessException;
+
+    void transaction(Consumer<JdbcTemplate> consumer);
+}

src/main/java/ru/di9/jdbc/JdbcTemplateImpl.java

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+package ru.di9.jdbc;
+
+import org.intellij.lang.annotations.Language;
+
+import javax.sql.DataSource;
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public class JdbcTemplateImpl implements JdbcTemplate {
+    private final DataSource dataSource;
+
+    public JdbcTemplateImpl(DataSource dataSource) {
+        this.dataSource = dataSource;
+    }
+
+    @Override
+    public void execute(@Language("GenericSQL") String sql) throws DataAccessException {
+        try (Connection connection = dataSource.getConnection();
+             Statement statement = connection.createStatement()) {
+            statement.execute(sql);
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public void execute(@Language("GenericSQL") String sql, PreparedStatementProcessor psp) throws DataAccessException {
+        try (Connection connection = dataSource.getConnection();
+             PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+            psp.process(preparedStatement);
+            preparedStatement.execute();
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> T query(@Language("GenericSQL") String sql, ResultSetExtractor<T> rse) throws DataAccessException {
+        try (Connection connection = dataSource.getConnection();
+             Statement statement = connection.createStatement();
+             ResultSet resultSet = statement.executeQuery(sql)) {
+            return rse.extractData(resultSet);
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> T query(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                       ResultSetExtractor<T> rse) throws DataAccessException {
+        try (Connection connection = dataSource.getConnection();
+             PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+            psp.process(preparedStatement);
+            try (ResultSet resultSet = preparedStatement.executeQuery()) {
+                return rse.extractData(resultSet);
+            }
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> Optional<T> queryOne(@Language("GenericSQL") String sql,
+                                    ResultSetExtractor<T> rse) throws DataAccessException {
+        return query(sql, rs -> {
+            if (rs.next()) {
+                return Optional.ofNullable(rse.extractData(rs));
+            } else {
+                return Optional.empty();
+            }
+        });
+    }
+
+    @Override
+    public <T> Optional<T> queryOne(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                                    ResultSetExtractor<T> rse) throws DataAccessException {
+        return query(sql, psp, rs -> {
+            if (rs.next()) {
+                return Optional.ofNullable(rse.extractData(rs));
+            } else {
+                return Optional.empty();
+            }
+        });
+    }
+
+    @Override
+    public <T> List<T> queryList(@Language("GenericSQL") String sql,
+                                 final RowMapper<T> rowMapper) throws DataAccessException {
+        return query(sql, createResultSetExtractorList(rowMapper));
+    }
+
+    @Override
+    public <T> List<T> queryList(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                                 final RowMapper<T> rowMapper) throws DataAccessException {
+        return query(sql, psp, createResultSetExtractorList(rowMapper));
+    }
+
+    @Override
+    public <T> T insert(@Language("GenericSQL") String sql, PreparedStatementProcessor psp,
+                        ResultSetExtractor<T> processGeneratedKey) throws DataAccessException {
+        try (Connection connection = dataSource.getConnection();
+             PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
+            psp.process(preparedStatement);
+            preparedStatement.execute();
+            try (ResultSet generatedKeys = preparedStatement.getGeneratedKeys()) {
+                generatedKeys.next();
+                return processGeneratedKey.extractData(generatedKeys);
+            }
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public void transaction(Consumer<JdbcTemplate> consumer) {
+        Connection connection = null;
+        try {
+            connection = dataSource.getConnection();
+            connection.createStatement().execute("BEGIN TRANSACTION");
+            consumer.accept(new JdbcTemplateTransactional(connection));
+            connection.createStatement().execute("COMMIT");
+        } catch (SQLException e) {
+            if (connection != null) {
+                try {
+                    connection.createStatement().execute("ROLLBACK");
+                    throw new DataAccessException("Error transaction", e);
+                } catch (SQLException e1) {
+                    DataAccessException exception = new DataAccessException("Error rollback", e1);
+                    exception.addSuppressed(e1);
+                    throw exception;
+                }
+            }
+        } finally {
+            if (connection != null) {
+                try {
+                    connection.close();
+                } catch (SQLException e) {
+                    throw new DataAccessException("Error close connection", e);
+                }
+            }
+        }
+    }
+
+    private <T> ResultSetExtractor<List<T>> createResultSetExtractorList(final RowMapper<T> rowMapper) {
+        return rs -> {
+            List<T> resultList;
+            int rowNum = 0;
+            if (rs.next()) {
+                resultList = new ArrayList<>();
+
+                do {
+                    resultList.add(rowMapper.mapRow(rs, rowNum++));
+                } while (rs.next());
+            } else {
+                resultList = Collections.emptyList();
+            }
+
+            return resultList;
+        };
+    }
+
+    static DataAccessException throwDataAccessException(String sql, Exception e) {
+        return new DataAccessException("Error execute SQL", sql, e);
+    }
+}

src/main/java/ru/di9/jdbc/JdbcTemplateTransactional.java

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+package ru.di9.jdbc;
+
+import lombok.RequiredArgsConstructor;
+
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+import static ru.di9.jdbc.JdbcTemplateImpl.throwDataAccessException;
+
+@RequiredArgsConstructor
+public class JdbcTemplateTransactional implements JdbcTemplate, AutoCloseable {
+    private final Connection connection;
+
+    @Override
+    public void close() throws Exception {
+        connection.close();
+    }
+
+    @Override
+    public void execute(String sql) throws DataAccessException {
+        try (Statement statement = connection.createStatement()) {
+            statement.execute(sql);
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public void execute(String sql, PreparedStatementProcessor psp) throws DataAccessException {
+        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+            psp.process(preparedStatement);
+            preparedStatement.execute();
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> T query(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
+        try (Statement statement = connection.createStatement();
+             ResultSet resultSet = statement.executeQuery(sql)) {
+            return rse.extractData(resultSet);
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> T query(String sql, PreparedStatementProcessor psp, ResultSetExtractor<T> rse) throws DataAccessException {
+        try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+            psp.process(preparedStatement);
+            try (ResultSet resultSet = preparedStatement.executeQuery()) {
+                return rse.extractData(resultSet);
+            }
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public <T> Optional<T> queryOne(String sql, ResultSetExtractor<T> rse) throws DataAccessException {
+        return query(sql, rs -> {
+            if (rs.next()) {
+                return Optional.ofNullable(rse.extractData(rs));
+            } else {
+                return Optional.empty();
+            }
+        });
+    }
+
+    @Override
+    public <T> Optional<T> queryOne(String sql, PreparedStatementProcessor psp, ResultSetExtractor<T> rse) throws DataAccessException {
+        return query(sql, psp, rs -> {
+            if (rs.next()) {
+                return Optional.ofNullable(rse.extractData(rs));
+            } else {
+                return Optional.empty();
+            }
+        });
+    }
+
+    @Override
+    public <T> List<T> queryList(String sql, RowMapper<T> rowMapper) throws DataAccessException {
+        return query(sql, createResultSetExtractorList(rowMapper));
+    }
+
+    @Override
+    public <T> List<T> queryList(String sql, PreparedStatementProcessor psp, RowMapper<T> rowMapper) throws DataAccessException {
+        return query(sql, psp, createResultSetExtractorList(rowMapper));
+    }
+
+    @Override
+    public <T> T insert(String sql, PreparedStatementProcessor psp, ResultSetExtractor<T> processGeneratedKey) throws DataAccessException {
+        try (PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
+            psp.process(preparedStatement);
+            preparedStatement.execute();
+            try (ResultSet generatedKeys = preparedStatement.getGeneratedKeys()) {
+                generatedKeys.next();
+                return processGeneratedKey.extractData(generatedKeys);
+            }
+        } catch (SQLException e) {
+            throw throwDataAccessException(sql, e);
+        }
+    }
+
+    @Override
+    public void transaction(Consumer<JdbcTemplate> consumer) {
+        consumer.accept(this);
+    }
+
+    private <T> ResultSetExtractor<List<T>> createResultSetExtractorList(final RowMapper<T> rowMapper) {
+        return rs -> {
+            List<T> resultList;
+            int rowNum = 0;
+            if (rs.next()) {
+                resultList = new ArrayList<>();
+
+                do {
+                    resultList.add(rowMapper.mapRow(rs, rowNum++));
+                } while (rs.next());
+            } else {
+                resultList = Collections.emptyList();
+            }
+
+            return resultList;
+        };
+    }
+}

src/main/java/ru/di9/jdbc/PreparedStatementProcessor.java

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+package ru.di9.jdbc;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface PreparedStatementProcessor {
+
+    void process(PreparedStatement ps) throws SQLException;
+}

src/main/java/ru/di9/jdbc/ResultSetExtractor.java

@@ -0,0 +1,10 @@
+package ru.di9.jdbc;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+@FunctionalInterface
+public interface ResultSetExtractor<T> {
+
+    T extractData(ResultSet rs) throws SQLException, DataAccessException;
+}

src/main/java/ru/di9/jdbc/ReturnGeneratedKeyHelper.java

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+package ru.di9.jdbc;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class ReturnGeneratedKeyHelper {
+    public static final ResultSetExtractor<Long> RETURN_GENERATED_KEY_FIRST_LONG = rs -> rs.getLong(1);
+    public static final ResultSetExtractor<Integer> RETURN_GENERATED_KEY_FIRST_INT = rs -> rs.getInt(1);
+}

src/main/java/ru/di9/jdbc/RowMapper.java

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+package ru.di9.jdbc;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public interface RowMapper<T> {
+
+    T mapRow(ResultSet rs, int rowNum) throws SQLException;
+}