Adding a Pre-constructed Bean to a Spring Application Context

Question

I am writing a class that implements the following method:

public void run(javax.sql.DataSource dataSource);

Within this method, I wish to

Answer 1

You can create a wrapper class for a DataSource that simply delegates to a contained DataSource

public class DataSourceWrapper implements DataSource {

DataSource dataSource;

public void setDataSource(DataSource dataSource) {
    this.dataSource = dataSource;
}

@Override
public Connection getConnection() throws SQLException {
    return dataSource.getConnection();
}

@Override
public Connection getConnection(String username, String password)
        throws SQLException {
    return dataSource.getConnection(username, password);
}
//delegate to all the other DataSource methods
}

Then in you Spring context file you declare DataSourceWrapper and wire it into all your beans. Then in your method you get a reference to DataSourceWrapper and set the wrapped DataSource to the one passed in to your method.

This all working is highly depended on what happens in your Spring context file when its being loaded. If a bean requires the DataSource to already be available when the context loads then you may have to write a BeanFactoryPostProcessor that alters the Spring context file as it loads, rather then doing things after the load (though perhaps a lazy-init could solve this issue).