JNDI DataSource implementation

DataSourceHierarchyContextFactory.java

import com.microsoft.sqlserver.jdbc.SQLServerDataSource;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.naming.spi.InitialContextFactory;
import javax.sql.DataSource;
import java.util.Hashtable;

public class DataSourceHierarchyContextFactory implements InitialContextFactory {

    private final Context hierarchy;

    public DataSourceHierarchyContextFactory() {
        DataSource dataSource = getDataSource("localhost", 0, "database", "username", "password");
        try {
            hierarchy = getContextWrapper(getContextWrapper(dataSource));
        } catch (NamingException e) {
            throw new IllegalStateException("Can't create Context", e);
        }
    }

    @Override
    public Context getInitialContext(Hashtable<?, ?> environment) {
        return hierarchy;
    }

    private Context getContextWrapper(Object object) throws NamingException {
        return new InitialContext(true) {
            public Object lookup(String name) {
                return object;
            }
        };
    }

    private static DataSource getDataSource(String host, int port, String database, String user, String password) {
        SQLServerDataSource ds = new SQLServerDataSource();
        ds.setServerName(host);
        ds.setPortNumber(port);
        ds.setDatabaseName(database);
        ds.setUser(user);
        ds.setPassword(password);
        return ds;
    }
}


import org.junit.BeforeClass;

import javax.naming.Context;
import javax.naming.NamingException;

public class JndiDataSourceTest {

    @BeforeClass
    public static void setup() throws NamingException {
        System.setProperty(Context.INITIAL_CONTEXT_FACTORY, DataSourceHierarchyContextFactory.class.getCanonicalName());
    }

    @Test
    public void createDataSource throws SQLException {
        Context initContext = new InitialContext();
	Context envContext = (Context) initContext.lookup("java:/contexts/database");
	DataSource dataSource = (DataSource) envContext.lookup("application-connection");
        ResultSet resultSet = dataSource.getConnection().createStatement().executeQuery("SELECT 1");
        resultSet.next();
        int one = resultSet.getInt(1);
        Assert.assertEquals(1, one);
    }
}

Steps to create JNDI:

1. Create Context: (specify true for lazy loading)

new InitialContext(true) {
    public Object lookup(String name) {
        return object;
    }
};

2. Create ContextFactory:

public class JndiContextFactory implements InitialContextFactory {
    @Override
    public Context getInitialContext(Hashtable<?, ?> environment) {
        return context;
    }
}

3. Register ContextFactory in JNDI:

System.setProperty(Context.INITIAL_CONTEXT_FACTORY, JndiContextFactory.class.getCanonicalName());