Package org.dbunit.database

Class CachingConnectionProvider

java.lang.Object
org.dbunit.database.CachingConnectionProvider
public class CachingConnectionProvider extends Object
Caches a single IDatabaseConnection so that it - and the table metadata it accumulates - can be reused across many test methods instead of being rebuilt on every call.

A Callable supplies the connection-creation logic; the factory is only invoked when there is no cached connection yet, or when the previously cached one is no longer alive. A dead connection is closed and transparently replaced rather than returned to the caller or left for the next call to fail on.

Usage. Construct one instance per target database and share that same instance across the JdbcDatabaseTester, DataSourceDatabaseTester, JndiDatabaseTester or DefaultDatabaseTester instances that are created for each test, for example via a static field on a common test base class: 

 private static final CachingConnectionProvider CONNECTION_PROVIDER =
         new CachingConnectionProvider();

 @BeforeEach
 void setUp() throws Exception
 {
     final IDatabaseTester tester = new JdbcDatabaseTester(driverClass,
             connectionUrl, username, password, schema, CONNECTION_PROVIDER);
     // The default IOperationListener closes the connection after every
     // onSetup()/onTearDown() call, which would defeat the cache. Pair it
     // with a listener that leaves the connection open, e.g.:
     tester.setOperationListener(IOperationListener.NO_OP_OPERATION_LISTENER);
     ...
 }

Thread safety. Access to the cached connection is synchronized, so concurrent callers cannot create or replace it at the same time. The returned IDatabaseConnection - and the underlying JDBC Connection it wraps - is however not synchronized, so this class is only appropriate for test suites that run sequentially, not for test methods executing concurrently against the same cached connection.

Metadata staleness. Because the whole point of reuse is to avoid re-fetching table metadata, a cached connection's DatabaseDataSet does not notice schema changes (new/dropped/altered tables) made after it was first cached. Do not share a provider across tests that alter DDL mid-run.

Since:
3.4.0

  • Field Details

  • Constructor Details

    • CachingConnectionProvider

      public CachingConnectionProvider()
      Creates a provider that validates the cached connection with the default validation timeout.

    • CachingConnectionProvider

      public CachingConnectionProvider(int validationTimeoutSeconds)
      Creates a provider that validates the cached connection with the given timeout.
      Parameters:
      validationTimeoutSeconds - The number of seconds Connection.isValid(int) is allowed to take when checking whether the cached connection is still alive. Zero means no timeout is applied.

  • Method Details

    • getConnection

      public IDatabaseConnection getConnection(Callable<IDatabaseConnection> connectionFactory) throws Exception
      Returns the cached connection, creating it with the given factory on the first call and again whenever the previously cached connection is no longer alive.
      Parameters:
      connectionFactory - Creates a new connection. Only invoked when there is no live cached connection to reuse.
      Returns:
      The cached, live connection.
      Throws:
      Exception - If connectionFactory throws while creating a new connection.

    • close

      public void close() throws SQLException
      Closes and discards the cached connection, if any. The next call to getConnection(Callable) creates a fresh one.
      Throws:
      SQLException - If closing the cached connection fails.

    • toString

      public String toString()
      Overrides:
      toString in class Object