Utilities and Tools

public class JDBCUtils {
    /**
     * Safely close a JDBC connection, ignoring any exceptions
     * @param connection Connection to close
     */
    public static void safeClose(Connection connection);
    
    /**
     * Safely close a JDBC statement, ignoring any exceptions
     * @param statement Statement to close
     */
    public static void safeClose(Statement statement);
    
    /**
     * Safely close a JDBC result set, ignoring any exceptions
     * @param resultSet ResultSet to close
     */
    public static void safeClose(ResultSet resultSet);
    
    /**
     * Safely close multiple JDBC resources, ignoring any exceptions
     * @param closeables Resources to close
     */
    public static void safeClose(AutoCloseable... closeables);
    
    /**
     * Detect the SQL dialect from a JDBC connection
     * @param connection JDBC connection to analyze
     * @return SQLDialect detected from the connection
     */
    public static SQLDialect dialect(Connection connection);
    
    /**
     * Detect the SQL dialect from a database URL
     * @param url JDBC URL to analyze
     * @return SQLDialect detected from the URL
     */
    public static SQLDialect dialect(String url);
    
    /**
     * Check if a connection is still valid
     * @param connection Connection to test
     * @param timeout Timeout in seconds for the test
     * @return true if connection is valid
     */
    public static boolean isValid(Connection connection, int timeout);
    
    /**
     * Get database product name from connection metadata
     * @param connection JDBC connection
     * @return Database product name
     */
    public static String getDatabaseProductName(Connection connection);
    
    /**
     * Get database product version from connection metadata
     * @param connection JDBC connection
     * @return Database product version
     */
    public static String getDatabaseProductVersion(Connection connection);
    
    /**
     * Create a data source from a JDBC URL
     * @param url JDBC connection URL
     * @param username Database username
     * @param password Database password
     * @return DataSource instance
     */
    public static DataSource dataSource(String url, String username, String password);
}

// Safe resource cleanup
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;

try {
    conn = DriverManager.getConnection("jdbc:h2:mem:test");
    stmt = conn.createStatement();
    rs = stmt.executeQuery("SELECT * FROM users");
    
    // Process results...
    
} catch (SQLException e) {
    // Handle error
} finally {
    // Safe cleanup - no exceptions thrown
    JDBCUtils.safeClose(rs, stmt, conn);
}

// Dialect detection
Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost/test");
SQLDialect dialect = JDBCUtils.dialect(conn);
System.out.println("Detected dialect: " + dialect); // POSTGRES

// Connection validation
if (JDBCUtils.isValid(conn, 5)) {
    // Connection is still good, use it
    DSLContext create = using(conn, dialect);
} else {
    // Connection is stale, get a new one
    conn = dataSource.getConnection();
}

public interface MockDataProvider {
    /**
     * Provide mock results for a SQL execution
     * @param ctx Mock execution context with SQL and parameters
     * @return Array of mock results
     * @throws SQLException if mock execution should simulate an error
     */
    MockResult[] execute(MockExecuteContext ctx) throws SQLException;
}

public class MockConnection implements Connection {
    /**
     * Create a mock connection with a data provider
     * @param provider MockDataProvider for generating results
     */
    public MockConnection(MockDataProvider provider);
    
    /**
     * Create a mock connection with multiple data providers
     * @param providers Array of MockDataProvider instances
     */
    public MockConnection(MockDataProvider... providers);
}

public class MockResult {
    /**
     * Create a mock result for a query
     * @param rows Number of rows affected/returned
     * @param data Result data as jOOQ Result
     */
    public MockResult(int rows, Result<? extends Record> data);
    
    /**
     * Create a mock result for DML operations
     * @param rows Number of rows affected
     */
    public MockResult(int rows);
    
    /**
     * Get the number of rows affected
     * @return Row count
     */
    public int rows();
    
    /**
     * Get the result data
     * @return Result data or null for DML operations
     */
    public Result<? extends Record> data();
}

public interface MockExecuteContext {
    /**
     * Get the SQL being executed
     * @return SQL string
     */
    String sql();
    
    /**
     * Get the bind values
     * @return Array of parameter values
     */
    Object[] bindings();
    
    /**
     * Get the SQL with inlined parameters
     * @return SQL with parameters substituted
     */
    String sqlInlined();
}

// Simple mock data provider
MockDataProvider provider = new MockDataProvider() {
    @Override
    public MockResult[] execute(MockExecuteContext ctx) throws SQLException {
        String sql = ctx.sql();
        
        if (sql.toUpperCase().startsWith("SELECT")) {
            // Mock SELECT results
            DSLContext create = using(SQLDialect.H2);
            Result<Record> result = create.newResult(
                field("id", Integer.class),
                field("name", String.class)
            );
            
            result.add(create.newRecord(result.fields())
                .values(1, "John Doe"));
            result.add(create.newRecord(result.fields())
                .values(2, "Jane Smith"));
                
            return new MockResult[] { new MockResult(2, result) };
            
        } else if (sql.toUpperCase().startsWith("INSERT")) {
            // Mock INSERT result
            return new MockResult[] { new MockResult(1) };
            
        } else {
            throw new SQLException("Unexpected SQL: " + sql);
        }
    }
};

// Use mock connection in tests
Connection mockConn = new MockConnection(provider);
DSLContext create = using(mockConn, SQLDialect.H2);

// This will use the mock provider
Result<Record> authors = create.select()
    .from("authors")
    .fetch();

assertEquals(2, authors.size());
assertEquals("John Doe", authors.get(0).get("name"));

public class Convert {
    /**
     * Convert a value to a specific type
     * @param from Value to convert
     * @param toClass Target type class
     * @return Converted value
     */
    public static <T> T convert(Object from, Class<T> toClass);
    
    /**
     * Convert a value using a specific converter
     * @param from Value to convert
     * @param converter Converter instance
     * @return Converted value
     */
    public static <T, U> U convert(T from, Converter<T, U> converter);
    
    /**
     * Check if conversion is possible between two types
     * @param from Source type
     * @param to Target type
     * @return true if conversion is supported
     */
    public static boolean canConvert(Class<?> from, Class<?> to);
    
    /**
     * Convert an array of values to a specific type
     * @param from Array of values to convert
     * @param toClass Target component type
     * @return Array with converted values
     */
    public static <T> T[] convertArray(Object[] from, Class<T> toClass);
    
    /**
     * Convert a collection to a list of specific type
     * @param from Collection to convert
     * @param toClass Target element type
     * @return List with converted elements
     */
    public static <T> List<T> convertCollection(Collection<?> from, Class<T> toClass);
}

public class JSONObject {
    /**
     * Create an empty JSON object
     */
    public JSONObject();
    
    /**
     * Create a JSON object from a string
     * @param json JSON string to parse
     */
    public JSONObject(String json);
    
    /**
     * Put a key-value pair in the JSON object
     * @param key JSON key
     * @param value JSON value
     * @return This JSONObject for chaining
     */
    public JSONObject put(String key, Object value);
    
    /**
     * Get a value by key
     * @param key JSON key
     * @return Value or null if not found
     */
    public Object get(String key);
    
    /**
     * Get a typed value by key
     * @param key JSON key
     * @param type Expected value type
     * @return Typed value or null if not found
     */
    public <T> T get(String key, Class<T> type);
    
    /**
     * Convert to JSON string
     * @return JSON string representation
     */
    public String toJSONString();
}

public class JSONArray {
    /**
     * Create an empty JSON array
     */
    public JSONArray();
    
    /**
     * Create a JSON array from a string
     * @param json JSON array string to parse
     */
    public JSONArray(String json);
    
    /**
     * Add a value to the array
     * @param value Value to add
     * @return This JSONArray for chaining
     */
    public JSONArray add(Object value);
    
    /**
     * Get a value by index
     * @param index Array index
     * @return Value at index
     */
    public Object get(int index);
    
    /**
     * Get array size
     * @return Number of elements
     */
    public int size();
    
    /**
     * Convert to JSON string
     * @return JSON array string representation
     */
    public String toJSONString();
}

public class JSONParser {
    /**
     * Parse a JSON string into an object
     * @param json JSON string to parse
     * @return JSONObject or JSONArray
     */
    public static Object parse(String json);
    
    /**
     * Parse a JSON string into a JSONObject
     * @param json JSON object string
     * @return JSONObject instance
     */
    public static JSONObject parseObject(String json);
    
    /**
     * Parse a JSON string into a JSONArray
     * @param json JSON array string
     * @return JSONArray instance
     */
    public static JSONArray parseArray(String json);
}

// Working with JSON data
JSONObject author = new JSONObject()
    .put("id", 1)
    .put("firstName", "John")
    .put("lastName", "Doe")
    .put("active", true);

String jsonString = author.toJSONString();
// {"id":1,"firstName":"John","lastName":"Doe","active":true}

// Parse JSON from database
Result<Record1<String>> jsonResults = create
    .select(field("author_data", String.class))
    .from("authors")
    .fetch();

for (Record1<String> record : jsonResults) {
    JSONObject authorData = JSONParser.parseObject(record.value1());
    String name = authorData.get("firstName", String.class);
    Integer id = authorData.get("id", Integer.class);
}

// Type conversion with JSON
Object value = "123";
Integer intValue = Convert.convert(value, Integer.class);
String stringValue = Convert.convert(intValue, String.class);

public class CSVReader {
    /**
     * Create a CSV reader from a file
     * @param file CSV file to read
     */
    public CSVReader(File file);
    
    /**
     * Create a CSV reader from an input stream
     * @param inputStream Stream containing CSV data
     */
    public CSVReader(InputStream inputStream);
    
    /**
     * Read the next CSV record
     * @return Array of field values or null if end of file
     */
    public String[] readNext();
    
    /**
     * Read all CSV records
     * @return List of string arrays representing records
     */
    public List<String[]> readAll();
    
    /**
     * Close the CSV reader
     */
    public void close();
}

public class CSVParser {
    /**
     * Parse a CSV line into fields
     * @param csvLine CSV line to parse
     * @return Array of field values
     */
    public static String[] parseLine(String csvLine);
    
    /**
     * Parse CSV line with custom separator
     * @param csvLine CSV line to parse
     * @param separator Field separator character
     * @return Array of field values
     */
    public static String[] parseLine(String csvLine, char separator);
}

public class Reflect {
    /**
     * Create a Reflect wrapper around an object
     * @param object Object to wrap
     * @return Reflect instance
     */
    public static Reflect on(Object object);
    
    /**
     * Create a Reflect wrapper around a class
     * @param clazz Class to wrap
     * @return Reflect instance
     */
    public static Reflect on(Class<?> clazz);
    
    /**
     * Create a new instance of the wrapped class
     * @param args Constructor arguments
     * @return New Reflect instance wrapping the created object
     */
    public Reflect create(Object... args);
    
    /**
     * Call a method on the wrapped object
     * @param name Method name
     * @param args Method arguments
     * @return Reflect instance wrapping the method result
     */
    public Reflect call(String name, Object... args);
    
    /**
     * Get a field value from the wrapped object
     * @param name Field name
     * @return Reflect instance wrapping the field value
     */
    public Reflect field(String name);
    
    /**
     * Set a field value on the wrapped object
     * @param name Field name
     * @param value New field value
     * @return This Reflect instance for chaining
     */
    public Reflect set(String name, Object value);
    
    /**
     * Get the wrapped object
     * @return The underlying object
     */
    public <T> T get();
    
    /**
     * Get the wrapped object as a specific type
     * @param type Target type class
     * @return The underlying object cast to the target type
     */
    public <T> T get(Class<T> type);
}

// Reflection utilities for POJO mapping
public class AuthorPojo {
    private String firstName;
    private String lastName;
    
    // getters and setters...
}

// Use reflection to create and populate POJO
Reflect authorReflect = Reflect.on(AuthorPojo.class).create();
authorReflect
    .set("firstName", "John")
    .set("lastName", "Doe");

AuthorPojo author = authorReflect.get(AuthorPojo.class);

// Call methods via reflection
String fullName = Reflect.on(author)
    .call("getFirstName")
    .get(String.class) + " " + 
    Reflect.on(author)
    .call("getLastName")
    .get(String.class);

// CSV bulk loading example
try (CSVReader reader = new CSVReader(new File("authors.csv"))) {
    List<String[]> records = reader.readAll();
    
    for (String[] record : records) {
        create.insertInto(AUTHOR)
            .set(AUTHOR.FIRST_NAME, record[0])
            .set(AUTHOR.LAST_NAME, record[1])
            .set(AUTHOR.EMAIL, record[2])
            .execute();
    }
}

public class R2DBCUtils {
    /**
     * Convert a reactive R2DBC result to jOOQ Result
     * @param publisher R2DBC result publisher
     * @param recordType Target record type
     * @return CompletableFuture with jOOQ Result
     */
    public static <R extends Record> CompletableFuture<Result<R>> 
        collect(Publisher<R> publisher, Class<R> recordType);
    
    /**
     * Execute a jOOQ query reactively with R2DBC
     * @param query jOOQ query to execute
     * @param connection R2DBC connection
     * @return Publisher of records
     */
    public static <R extends Record> Publisher<R> 
        executeAsync(Query query, io.r2dbc.spi.Connection connection);
}

// Reactive query execution
io.r2dbc.spi.ConnectionFactory factory = 
    ConnectionFactories.get("r2dbc:postgresql://localhost/test");

DSLContext create = using(factory);

// Reactive SELECT
Publisher<AuthorRecord> authorsPublisher = create
    .selectFrom(AUTHOR)
    .where(AUTHOR.ACTIVE.eq(true))
    .fetchPublisher();

// Convert to CompletableFuture
CompletableFuture<Result<AuthorRecord>> authorsFuture = 
    R2DBCUtils.collect(authorsPublisher, AuthorRecord.class);

authorsFuture.thenAccept(authors -> {
    System.out.println("Found " + authors.size() + " active authors");
});