fjdbc: functional wrapper for the JDBC API

fjdbc is a lightweight library to write JDBC code in a more convenient and functional style.

fjdbc is built around a small number of abstractions:

• ConnectionProvider is responsible for getting java.sql.Connection instances.
• DbOperation represents either a single java.sql.Statement, or a sequence of Statements to be executed in a single transaction.
• ResultSetExtractor is a functional interface to extract objects from a java.sql.ResultSet.
• PreparedStatementBinder is a functional interface to bind the parameters of a java.sql.PreparedStatement.
• Query represents a SQL SELECT statement.
• Fjdbc is the library façade.
• SQLException instances are wrapped in an unchecked RuntimeSQLException.

Requires Java >= 8.

Install (Maven)

<dependency>
    <groupId>com.github.ewanld</groupId>
    <artifactId>fjdbc</artifactId>
    <version>0.1.0</version>
</dependency>

Build from source

mvn package

Examples

Setup

final Connection connection = DriverManager.getConnection("jdbc/url/to/database");
final ConnectionProvider cnxProvider = new SingleConnectionProvider(connection);
final Fjdbc fjdbc = new Fjdbc(cnxProvider);

Query the database

final String sql = "select name from user";
final SingleRowExtractor<String> extractor = (rs) -> rs.getString("name");
final List<String> names = fjdbc.query(sql, extractor).toList();

Query the database using a prepared statement

final String sql = "select name from user where role = ?";
final SingleRowExtractor<String> extractor = rs -> rs.getString("name");
final List<String> names = fjdbc
	.query(sql, extractor)
	.setBinder((ps, seq) -> ps.setString(seq.next(), "grunt"))
	.toList();

Execute a statement (update, delete, insert, etc)

final String sql = "update user set name='jack' where name='henri'";
final int nRows = fjdbc.statement(sql).executeAndCommit();

Execute a prepared statement

final String sql = "update user set name=? where name=?";
final int nRows = fjdbc
	.statement(sql)
	.setBinder((ps, seq) -> {
		ps.setString(seq.next(), "jack");
		ps.setString(seq.next(), "henri");
	})
	.executeAndCommit();

Execute a sequence of statements (in a single transaction)

final StatementOperation updateName = fjdbc
	.statement("update user set name=? where name=?")
	.setBinder((ps, seq) -> {
		ps.setString(seq.next(), "jack");
		ps.setString(seq.next(), "henri");
	});

final StatementOperation deleteManagers = fjdbc
	.statement("delete from user where role=?")
	.setBinder((ps, seq) -> {
		ps.setString(seq.next(), "manager");
	});

final int nRows = fjdbc.composite(updateName, deleteManagers).executeAndCommit();