@Override
	protected BasicDataSource createInstance() throws Exception {
		BasicDataSource ds = new BasicDataSource();
		ds.setDriverClassName("org.postgresql.Driver");
		if (StringUtils.hasText(dbUser)) {
			ds.setUsername(dbUser);
		}
		if (StringUtils.hasText(dbPassword)) {
			ds.setPassword(dbPassword);
		}
		ds.setUrl("jdbc:postgresql://" + dbHost + ":" + dbPort + "/" + dbName);
		return ds;
	}
Factory bean for configuring a {@link DataSource}. Needed to use
both command-line props and a control file.

@author Janne Valkealahti
extensions/spring-xd-extension-gpfdist/src/main/java/org/springframework/xd/greenplum/support/GreenplumDataSourceFactoryBean.java