Hi Adolfo,
I wrote something which has been working well
for me - it makes extensive use of the Jakarta
Digester utility and some classes similar to
BeanUtils and PropertyUtils
Works something like this:
Can pass "simple" objects like Integer, String, Float
(the kinds that you can use in JDBC setObject calls) or beans.
Can get beans, simple objects, or arrays of each back as results.
Java like this:
public class UselessAction extends SubclassedAction {
// SubclassedAction extends Action and build a DaoFactory on
// startup, passing it in to the perform method of my application
// actions
performAction(ActionMapping mapping, blah blah, ActionForm form,
DaoFactory df) {
Customer[] customers;
DataAccessor dao = df.getDataAccessor("invoice");
// just a wrapper around a hashmap that takes care of primitive
// wrapping and java.util.Date -> java.sql.Date, etc
ParameterSet params = new ParameterSet();
params.addParameter("userId", 0)
dao.execute("retrieveCustomers", params);
customers = (Customer)dao.getResults(new Customer[0]);
Invoice invoice = new Invoice();
PropertyUtils.copyProperties(invoice, form);
ParameterSet invoiceParams = new ParameterSet();
params.addParameter("userId", 0)
invoiceParams.addParameter("invoice", invoice);
dao.execute("saveInvoice", params);
}
}
The DaoFactory is built on startup by Digester
The XML looks like this:
<daomap>
<connections>
<connection name="sam" alias="primary">
</connections>
<beans>
<bean name="com.kensfoods.example.Invoice" alias="invoice"/>
<bean name="com.kensfoods.example.Customer" alias="customer"/>
</beans>
<datasources>
<datasource>
<datasource-name>invoice</datasource-name>
<connection-alias>primary</connection-alias>
<method>
<method-name>retrieveCustomers</method-name>
<statement>
<call>{call sbrGetCustomers(?)}</call>
<input>
<parameter name="userId" position="1"
type="java.lang.Integer"/>
</input>
<output/>
</statement>
<result bean="customer">
<field property="customerId"/>
<field property="customerName"/>
<field property="address1"/>
<field property="address2"/>
<field property="address3"/>
<field property="city"/>
<!-- etc.... -->
</result>
</method>
<method>
<method>
<method-name>saveInvoice</method-name>
<statement>
<call>{? = call sbrPutInvoice(?,?,?,?,?,?,?,...</call>
<input>
<parameter name="userId" position="2"
type="java.lang.Integer"/>
<parameter name="invoiceId" bean="invoice" position="3"/>
<parameter name="invoiceNumber" bean="invoice"
position="4"/>
<!-- etc.... -->
<output>
<parameter name="return" position="1"
type="java.lang.Integer"/>
<parameter name="invoiceId" position="3"
type="java.lang.Integer"/>
</output>
</statement>
<post-call>
<set source="output" from="invoiceId" to="invoice"
to-property="invoiceId"/>
</post-call>
<result/>
</method>
</datasource>
</datasources>
</daomap>
It works great for me - I hope that this gives you some ideas,
Casey
> Subject: DAO open source? From: "Adolfo Miguelez"
> <[EMAIL PROTECTED]> Date: Tue, 14 May 2002 18:09:59 +0000 To:
> [EMAIL PROTECTED]
>
> Hi All,
>
> probably a little out of Struts scope but, not a problem for many of
> you, since it plugs in struts. I need to code an DAO class that, via
> JDBC, accesses a database. Database is Oracle 8i. We intend to manage
> any kind of database data.
> My employer suggested my that class could have a principal method
> execute(...) signed like that:
>
> public static HashMap execute(String query, String datasource, String
> DBuser, String DBpassword, ArrayList parameters);
>
> The class accesses PL/SQL stored procedures by means of
> CallableStatements, which actually hold the business logic.
>
> * Returned hashmap contains return values indexed by return parameter
> name, including arrayList converted form resulsets and
> * ArrayList parameters holds next info about each parameter:
> - IN/OUT/INOUT
> - type
> - value
> in order that method can be able to work out the actual
> CallableStatement.
> That is the scenario. However, I am not sure about this design, and I
> have some questions so, I would appreciate opinions.
>
> - Firstly, passing parameter types I think is quite messy for the
> programmer. Furthermore, method can inspect in runtime database column
> types and cast, or match itself, input parameter types for database
> types. I would free this (pointless?) load to programmer that use this
> class.
>
> - Maynbe using dynabeans rather than hashmaps in the return from the
> method,
>
> - is good idea to make execute() static?
>
> - Does any of you know a open source DAO, or example to look at?
>
> Regards,
>
> Adolfo.
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