[jboss-user] [JBoss Seam] - Creating and Updating records in single operation: sensible
Hi
I'm interested to hear people's opinions on the way I've implemented a
solution. I'd like to know if there's a cleaner or simpler pattern...
Requirement:
When a user clicks an 'update' button, create a new record in a table and also
update an existing record in the same table. The UI page uses <h:inputText/> fields.
Application flow:
1. User selects an existing record from a CRUD page and is presented with an edit page for
a that record
2. User edits some fields of that record and clicks 'update'
3. A new record must be created, which is a copy of the existing record but with any
fields the user changed in step 2 upated with those changes
4. Some non-UI fields of the existing record must be changed and the record then updated
in the table (this record must otherwise remain unchanged)
A solution:
Relevant code (abridged for brevity):
i. Edit page extract:
note: This page is rendered after the user selects a record from a different CRUD page.
<h:form>
|
| <s:decorate id="decoration" template="edit.xhtml">
| <h:inputText id="one"
| value="#{myEntityHome.instance.UIProperty}" >
| <a:support event="onblur" reRender="decoration"
| bypassUpdates="true" ajaxSingle="true" />
| </h:inputText>
| </s:decorate>
|
| <h:commandButton id="update" value="Update"
action="#{myEntityHome.update}" />
|
| </h:form>
ii. Extended Home component:
note:
a. find() is invoked in step 1 (when the user selects a record on the CRUD page).
b. update() is invoked in step 2 (when the user clicks the update button).
c. Assume MyEntity is a simple EJB Entity with properties corresponding to those
referenced below.
| @Name("myEntityHome")
| public class MyEntityHome extends EntityHome<MyEntity>
|
| private MyEntity existingEntity;
| private List<AssociatedEntityList> associatedEntityLists = new
ArrayList<AssociatedEntityList>();
|
| @In(create = true)
| EntityManager em;
|
| public List<AssociatedEntityList> getAssociatedEntityLists() {
| return associatedEntityLists;
| }
|
| @Override
| public MyEntity find() {
|
| // Store the contents of the existing entity
| MyEntity myEntity = super.find();
| existingEntity = new MyEntity(myEntity.getId(),
| myEntity.getUIProperty(),
| myEntity.getNonUIProperty(),
| myEntity.getAssociatedEntityLists());
| return myEntity;
| }
|
|
| @Begin(join = true, flushMode = FlushModeType.MANUAL)
| @Override
| @Transactional
| public String update() {
|
| // For step 3
| MyEntity myEntity = createNewEntity();
|
| // For step 4: Refresh the existing entity as the user may have changed
| // some UI fields, which must not be updated in the db
| em.refresh(getInstance());
|
| // For step 4
| getInstance().setNonUIProperty("changed");
|
| entityManager.flush();
| Contexts.removeFromAllContexts("myEntityHome");
| return "createdAndUpdated";
| }
|
|
| private MyEntity createNewEntity() {
|
| MyEntity myEntity = new MyEntity();
|
| // Copy contents of current UI fields into the newly created entity
| myEntity.setUIPropertyOne(getInstance().getUIPropertyOne());
|
| // Copy contents of non-UI fields into the newly created entity
| myEntity.setNonUIPropertyOne(getInstance().getNonUIPropertyOne());
|
| // Copy associated entities into the newly created entity
| for (AssociatedEntityList ael : associatedEntityLists)
| ael.setMyEntity(myEntity);
| myEntity.setAssociatedEntityLists(associatedEntityLists);
|
| return myEntity;
| }
As you can see, I'm using EntityManager refreshing and manual flushing and am having
to make a 'clone' (which could be done by implementing Cloneable instead) of the
existing entity in createNewEntity().
Any feedback appreciated...
Thanks
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