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package org.kiwiproject.test.jdbc;
import static org.kiwiproject.base.KiwiPreconditions.requireNotBlank;
import static org.kiwiproject.base.KiwiPreconditions.requireNotNull;
import static org.kiwiproject.base.KiwiStrings.f;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.kiwiproject.jdbc.UncheckedSQLException;
import java.io.Closeable;
import java.io.PrintWriter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.Objects;
import java.util.logging.Logger;
import javax.sql.DataSource;
/**
* A very simple implementation of {@link DataSource} intended to be used only during tests. As its name
* suggests, this implementation stores a single {@link Connection} which is always returned by the
* {@code getConnection} methods.
*
* Note specifically that the single connection ignores calls to {@code close()}, since we do not expect the
* code under test to close connections. To close the single connection, close this instance, which implements
* {@link Closeable} in addition to {@link DataSource}.
*
* The single Connection is eagerly initialized during construction since the expected usage pattern is to create an
* object before all tests run (e.g. using a JUnit {@code @BeforeAll}). Therefore, we keep things simple by eagerly
* initializing instead of waiting for the first {@code getConnection} call to occur.
*
* To be very clear, this is intended to be used only during tests, and specifically in tests that execute within
* a transaction that is rolled back once each test has executed. This ensures no data is actually stored in the
* database making for faster tests (due to no commit overhead) and also permits testing simultaneously against
* a shared database, for example a database setup for multiple developers or continuous integration servers to
* run tests against.
*
* This simple implementation does not support all of the {@link DataSource} methods. See the docs for each method.
*
* @implNote This is heavily influenced from and some code copied from Spring's {@code SingleConnectionDataSource}
* but is much simpler since we do not need it to be as generic as Spring's version. We mostly used the code
* relating to the {@link InvocationHandler} that ignores calls to close a {@code Connection}, but are only handling
* one method {@code close} that we want to intercept.
*/
@SuppressWarnings("RedundantThrows")
@Slf4j
public class SimpleSingleConnectionDataSource implements DataSource, Closeable {
/**
* The test database URL to be passed to {@link DriverManager}.
*
* @see DriverManager#getConnection(String, String, String)
*/
@Getter
private final String url;
/**
* The test database username to be passed to {@link DriverManager}.
*
* @see DriverManager#getConnection(String, String, String)
*/
@Getter
private final String username;
/**
* The test database password to be passed to {@link DriverManager}.
*
* @see DriverManager#getConnection(String, String, String)
*/
@Getter
private final String password;
/**
* The single Connection held by this instance.
*/
private final Connection connection;
/**
* A Connection proxy around {@code connection} that ignores calls to close it.
*/
private final Connection closeSuppressingConnection;
/**
* Create a new SingleConnectionDataSource with the given database URL and username.
* An empty password is supplied to {@link DriverManager}.
*
* The single Connection is eagerly initialized in this constructor.
*
* @param url the database URL
* @param username the database username
*/
public SimpleSingleConnectionDataSource(String url, String username) {
this(url, username, "");
}
/**
* Create a new SingleConnectionDataSource with the given database URL, username, and password
* to be supplied to {@link DriverManager}.
*
* The single Connection is eagerly initialized in this constructor.
*
* @param url the database URL
* @param username the database username
* @param password the database password
*/
public SimpleSingleConnectionDataSource(String url, String username, String password) {
this.url = requireNotBlank(url);
this.username = requireNotNull(username);
this.password = requireNotNull(password);
this.connection = getConnectionFromDriverManager(url, username, password);
this.closeSuppressingConnection = closeSuppressingProxyFor(connection);
}
private static Connection getConnectionFromDriverManager(String url, String username, String password) {
try {
return DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
throw new UncheckedSQLException(f("Error getting Connection for URL {} and username {}", url, username), e);
}
}
/**
* Closes the underlying single {@link Connection}. If any errors occur they are logged at WARN level but
* no exceptions are thrown.
*/
@Override
public void close() {
try {
connection.close();
} catch (Exception e) {
LOG.warn("Error closing single Connection {}", connection, e);
}
}
/**
* Always returns the single Connection stored in this DataSource.
*
* Attempts to close it will be ignored.
*
* @return the single Connection of this DataSource
* @implNote Ignoring Sonar warning about getters and setters using the "expected" fields. While named like
* a getter method, it isn't really a getter method and this rule doesn't apply.
*/
@Override
@SuppressWarnings("java:S4275")
public Connection getConnection() throws SQLException {
return closeSuppressingConnection;
}
/**
* Returns the single Connection if and only if the given username and password match the ones
* provided when this instance was constructed. It does not make sense to allow different username
* and password for the same exact Connection.
*
* @param username the database username
* @param password the database password
* @return the single Connection of this DataSource
* @throws SQLException if the given username and password don't match the ones assigned to this instance
* @implNote Adapted from Spring's {@code SingleConnectionDataSource}
*/
@Override
public Connection getConnection(String username, String password) throws SQLException {
if (Objects.equals(username, this.username) && Objects.equals(password, this.password)) {
return getConnection();
} else {
throw new SQLException("SimpleSingleConnectionDataSource does not support custom username and password");
}
}
/**
* Getting a log writer is not supported.
*
* Always throws an {@link UnsupportedOperationException}.
*/
@Override
public PrintWriter getLogWriter() throws SQLException {
throw new UnsupportedOperationException("getLogWriter");
}
/**
* Setting a log writer is not supported.
*
* Always throws an {@link UnsupportedOperationException}.
*/
@Override
public void setLogWriter(PrintWriter out) throws SQLException {
throw new UnsupportedOperationException("setLogWriter");
}
/**
* Setting a login timeout is not supported.
*/
@Override
public void setLoginTimeout(int seconds) throws SQLException {
throw new UnsupportedOperationException("setLoginTimeout");
}
/**
* Returns 0, indicating the default system timeout is to be used.
*/
@Override
public int getLoginTimeout() throws SQLException {
return 0;
}
/**
* Return a parent logger with the JUL global logger name.
*
* @return a Logger with the global logger name
* @see Logger#GLOBAL_LOGGER_NAME
*/
@Override
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
}
/**
* Returns {@code this} when the specified class is assignment-compatible with this instance.
*
* @throws SQLException if the specified class is not assignment-compatible with this instance
* @implNote This was copied from Spring's {@code SingleConnectionDataSource}.
* @see Class#isInstance(Object)
*/
@Override
@SuppressWarnings("unchecked")
public T unwrap(Class iface) throws SQLException {
if (iface.isInstance(this)) {
return (T) this;
}
throw new SQLException(f("DataSource of type {} cannot be unwrapped as {}",
getClass().getName(), iface.getName()));
}
/**
* Return true when the specified class is assignment-compatible with this instance.
*/
@Override
public boolean isWrapperFor(Class iface) throws SQLException {
return iface.isInstance(this);
}
/**
* Define a dynamic {@link Proxy} that suppresses any calls to {@link Connection#close()} on the
* single connection. We do not want anything actually closing this connection during a test's
* execution.
*
* @implNote Adapted from Spring's {@code SingleConnectionDataSource}.
*/
private static Connection closeSuppressingProxyFor(Connection target) {
requireNotNull(target, "Connection for proxy cannot be null");
return (Connection) Proxy.newProxyInstance(
Connection.class.getClassLoader(),
new Class[]{Connection.class},
new CloseSuppressingInvocationHandler(target));
}
/**
* Invocation handler that suppresses close calls on JDBC Connections.
*
* @implNote This was adapted from Spring's {@code SingleConnectionDataSource}.
*/
@Slf4j
private static class CloseSuppressingInvocationHandler implements InvocationHandler {
private final Connection target;
CloseSuppressingInvocationHandler(Connection target) {
this.target = target;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
var methodName = method.getName();
if ("close".equals(methodName)) {
LOG.trace("Suppressing call to close on target Connection {}", target);
return null;
}
LOG.trace("Invoke method {} on target Connection {}", methodName, target);
try {
return method.invoke(this.target, args);
} catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
}
}