make ofbiz more object friendly goes against the orginal design and
David has address why.
=========================
BJ Freeman
Strategic Power Office with Supplier Automation
<http://www.businessesnetwork.com/automation/viewforum.php?f=52>
Specialtymarket.com <http://www.specialtymarket.com/>
Systems Integrator-- Glad to Assist
Chat Y! messenger: bjfr33man
Marc Morin sent the following on 12/10/2010 7:20 AM:
In the spirit of changing the entity/delegator interface more object friendly, why not
take this to then next step and generate POJO interfaces for each entity. These would
extend GenericValue but provide a simple gettor/settor facade allowing compile time type
checking and removing of the "string" code for much of the business logic
written in java.
We have done such a thing (again in our forked application), and it makes the
Java code much more readable and easier to use. The general structure is
public class Person extends AbstractGenericValue<Person>
{
public static final String ENTITY = "Person";
// constructor, only called from makeValue, MUST be associated with a
delegator
protected Person(Delegator delegator) {...}
// factory method
public static Person newInstance(Delegator delegator) {...}
// generate finders, by pkey, etc...
public static Person findOne(Delegator delegator, String partyId){...}
// getter and settors
public String getFirstName() {
return getString("firstName");
}
public Person setFirstName(String value) {
set("firstName", value);
return this;
}
// relationships
public Party getParty() throws GenericEntityException {...}
public PartyNameView getPartyNameView() throws GenericEntityException{...}
}
This allows code that is much easier to debug and less error prone.. example
below is for navigating orders.
OrderHeader orderHeader = OrderHeader.findOne(delegator, orderId);
// get the orderItems
List<OrderItem> orderItems = orderHeader.getOrderItemList();
BigDecimal totalQuantity = BigDecimal.ZERO;
for (OrderItem orderItem: orderItems) {
totalQuantity = totalQuantity.add(orderItem.getQuantity());
}
I know we want to encourage business logic in minlang, etc... but if it is
written in java, and there is a LOT of code in java, shopping cart, etc...
this makes that code MUST more readable and maintainable. The binding between
the entity model and the java implementation can be caught as a compile time
error... significantly lowers the maintenance cost of the code.
This may be pushing a rope, but we use this ALL the time for our groovy and java code.
(would also apply to jsp code obviously). Minilang code can be type checked by the
reader... (want to check for static errors in code, without the need to "run"
the code).
We have implemented the generators, and the refactoring/abstracting to enable this. We
find it works great and doesn't break ANY of the nice ofbiz extend entity semantics,
etc.... Of course if you extend an entity and then want java business logic to use it...
you need to access those items either with "strings" as stock ofbiz, or redo an
entity-gen. But if there is no java code using the entities, no need to auto-gen.
As another note, we have done a similar thing with the service interface.... as you might
have guessed, we're a fan of ofbiz extensibility, but NOT on how it encourages poor Java
implementation practices. ("String" object references, non-type safe, public
static methods everywhere.... etc...)
Marc
----- Original Message -----
On 10/12/2010, at 8:54 AM, Adam Heath wrote:
On 12/09/2010 01:48 PM, Scott Gray wrote:
On 10/12/2010, at 5:53 AM, Adam Heath wrote:
On 12/09/2010 12:03 AM, Scott Gray wrote:
On 9/12/2010, at 11:50 AM, Adam Heath wrote:
On 12/08/2010 03:00 PM, Scott Gray wrote:
On 8/12/2010, at 4:29 AM, Adam Heath wrote:
I've deprecated findByAnd locally, replacing calls with a
variant that
takes a boolean, which specifies whether to use the cache.
Initially, my replacement just added a new findByAnd. However,
I'm now starting to lean towards replacing with findList
instead. However, in my opinion, I think that will make
programming ofbiz more
difficult.
I'd like to add a findList variant, that takes a Map instead
of an
EntityCondition. Without this new variant, there would be ton
of variants that would only need to import EntityCondition,
just to
create a condition.
There are also performance considerations to consider.
EntityCondition.makeCondition(Map) directly takes the map,
doing no
processing. However, EntityCondition.makeCondition(Object...)
eventually calls EntityUtil.makeFields, which does a little
more than
UtilMisc. In addition to the iteration over the array, it also
does a
check on the value for Comparable/Serializable. This latter
check seems a bit superfluous, as eventually the base
condition classes
check the values against the model.
So, from a purist stand point, even tho findByAnd could be
replaced by
findList, I think it is too useful; it saves enough code in
application layers, imho.
This reminded me of the query objects with method chaining that
I suggested a while back so I threw them together this morning.
Here are some examples:
thisContent = delegator.findByPrimaryKeyCache("Content",
UtilMisc.toMap("contentId", assocContentId));
// becomes
thisContent =
EntityOne.query(delegator).from("Content").where("contentId",
assocContentId).cache().find();
api: EntityOne(delegator).from()....
in foo.groovy:
use(DelegatorCategory) {
}
class DelegatorCategory {
public static EntityOneBuilder EntityOne(Delegator delegator) {
return new EntityOneBuilder(delegator);
}
} class EntityOneBuilder {
public EntityOneBuilder from(String entityName) {
return this;
}
public GenericValue query() {
return delegator.findOne(....);
}
}
This is almost like what you suggested, but it removes the
query() method that starts thte builder, and changes the find()
to query().
EntityList would be done the same one.
The way you have it, is that the start(EntityOne, EntityList)
and the end(find(), list()), are 2 things that have to be
remembered. My version just has one thing(the start of the
call).
This is all groovy DSL related though right? I hadn't worried
about groovy too much because I knew we had a fair bit of
flexibility thanks to the language features. The API I've written
to date was solely intended for java development but seems
succinct enough that not much would need to change for groovy.
Also EntityList's execute methods so far are:
list() iterator()
first() count()
All primary methods should be query(), imho.
interface GenericQueryBuilder<T> {
T query();
}
public class EntityOne implements
GenericQueryBuilder<GenericValue> {
public GenericValue query() {}
}
public class EntityList implements
GenericQueryBuilder<List<GenericValue>>, Iterable<GenericValue> {
public List<GenericValue> query() {}
public Iterator<GenericValue> iterator() {}
...
}
I'm not opposed to that, but I'll need another method name for
specifying the delegator. How about use(delegator)?
public final class EntityBuilderUtil {
public static EntityOne one(Delegator delegator) {
return new EntityOne(delegator);
}
public static EntityList list(Delegator delegator) {
return new EntityList(delegator);
}
}
This also means that java api code only needs to import one class.
Plus, if this class is used as a groovy category, then groovy code
can do this:
one(delegator).cache(true).....
As groovy will see one as a method call, taking a variable with type
Delegator, and search all its categories to find a matching method.
You'll get all things for free.
Works for me.
Thanks
Scott
