<Resource name="jdbc/postgres" auth="Container"
      type="javax.sql.DataSource" driverClassName="org.postgresql.Driver"
      url="jdbc:postgresql://localhost:5432/DB"
      username="user" password="pw" maxActive="20" maxIdle="10"
      maxWait="-1"
      factory="org.apache.commons.dbcp.BasicDataSourceFactory"
/>
<ResourceLink name="jdbc/postgres" global="jdbc/postgres"   type="javax.sql.DataSource" />