@PersistenceContext in a SFSB created by a factory

[newlukai]

Hi there,

is it possible to have a PersistenceContext in a bean (don't really know which type it is, sorry, I'm a noob somedays :D) which is created by a factory?

The thing I want to do is to imlpement the possibility to switch the implementation of an interface. This works. In one of these implementations I want to obtain the PersistenceContext and that doesn't work.

But let me show you some code:

@Name("upDownloadFactory")
@Scope(ScopeType.APPLICATION)
@Startup
public class UpDownloadFactory implements Serializable {
 private String className;

 @Out(required=false)
 private UpDownload upDownload;

 @Factory(value="upDownload", scope=ScopeType.SESSION, autoCreate=true)
 public UpDownload getUpDownload() {
 if(upDownload == null) {
 try {
 if(className == null || className.equals("")) {
 className = "com.idsscheer.ares.sessions.UpDownloadDatabase";
 }
 upDownload = (UpDownload) Class.forName(className).newInstance();
 ... and so on ...
 }

 return upDownload;
 }

 public void setClassName(String className) {
 this.className = className;
 }
}

This is the factory I wrote. As you can see the implementation has to be set in components.xml and sets the className property. All those parameters I set in the @Factory annotation shall setup the "upDownload" as SFSB.

Here is one implementation of the managed bean:

@Scope(ScopeType.SESSION)
@Stateful
public class UpDownloadDatabase implements UpDownload, Serializable {
 @PersistenceContext(unitName = "aresDatabase")
 private transient EntityManager em;

 public boolean upload(UpDownloadFileinfo fileInfo) {
 ... do the upload with em ...
 }

 public List<UpDownloadFileinfo> getAttachedFiles(long testactionID) {
 ... show a list of attached files ...
 }

 @Remove @Destroy
 public void destroy() {
 }
}

In this implementation the EntityManager is needed but on invokation of this bean the console tells me that

Caused by: java.lang.IllegalArgumentException: @PersistenceContext may only be used on session bean or message driven bean components: upDownload
 at org.jboss.seam.Component.initMembers(Component.java:663)
 at org.jboss.seam.Component.<init>(Component.java:253)
 at org.jboss.seam.Component.<init>(Component.java:203)
 at org.jboss.seam.init.Initialization.addComponent(Initialization.java:851)
 ... 93 more

Has anybody an idea how to implement such a factory?

Thanks in advance
Newlukai

[pmuir]

For Seam injection to work you have to instantiate the component through Seam e.g. Component.getInstance(). If you make the UpDownloadDatabase a Seam component then this is all you need to do.

If you want it as a non-seam SFSB, you need to ask EJB3 to instantiate it for you (e.g. JNDI lookup, @EJB).

[newlukai]

So I have to change the @Factory method to

upDownload = Component.getInstance("upDownload");

? But, the component "upDownload" isn't yet instantiated, so Seam would look up for "upDownload" and since the @Name is missing on UpDownloadDatabase it would just find the @Factory in UpDownloadFactory. I'm sure I've accidentally ignored something but for me it looks like this would be a recursive call, isn't it?

On the other side, when I call Component.getInstance() it isn't possible to switch the implementation via components.xml anymore?!?

A workaround would be sth like this:

@Name("upDownloadFactory")
@Scope(ScopeType.APPLICATION)
@Startup
public class UpDownloadFactory implements Serializable {
 private String className;

 @Out(required=false)
 private UpDownload upDownload;

 @Factory(value="upDownload", scope=ScopeType.SESSION, autoCreate=true)
 public UpDownload getUpDownload() {
 if(upDownload == null) {
 try {
 if(className == null || className.equals("")) {
 className = "Database";
 }
 upDownload = (UpDownload) Component.getInstance("upDownload"+className);
 ... and so on ...
 }

 return upDownload;
 }

 public void setClassName(String className) {
 this.className = className;
 }
}

@Scope(ScopeType.SESSION)
@Stateful
@Name("upDownloadDatabase")
public class UpDownloadDatabase implements UpDownload, Serializable {
 @PersistenceContext(unitName = "aresDatabase")
 private transient EntityManager em;

 public boolean upload(UpDownloadFileinfo fileInfo) {
 ... do the upload with em ...
 }

 public List<UpDownloadFileinfo> getAttachedFiles(long testactionID) {
 ... show a list of attached files ...
 }

 @Remove @Destroy
 public void destroy() {
 }
}

@Scope(ScopeType.SESSION)
@Stateful
@Name("upDownloadFilesystem")
public class UpDownloadFilesystem implements UpDownload, Serializable {
 public boolean upload(UpDownloadFileinfo fileInfo) {
 ... do the upload with em ...
 }

 public List<UpDownloadFileinfo> getAttachedFiles(long testactionID) {
 ... show a list of attached files ...
 }

 @Remove @Destroy
 public void destroy() {
 }
}

Would that be possible?

[pmuir]

"Newlukai" wrote:
So I have to change the @Factory method to

upDownload = Component.getInstance("upDownload");

? But, the component "upDownload" isn't yet instantiated, so Seam would look up for "upDownload" and since the @Name is missing on UpDownloadDatabase it would just find the @Factory in UpDownloadFactory. I'm sure I've accidentally ignored something but for me it looks like this would be a recursive call, isn't it?

Yes. Your desgin has flaws.

If all you want to do is switch out the implementation from components.xml then you can just.

<component name="upDownload" class="UpDownloadDatabase" />
<!--<component name="upDownload" class="UpDownloadFileSystem" />-->

and miss out the @Name annotations on the class. You don't need your factory.

[newlukai]

OK. I changed this. I'm wondering why I didn't do that before ...

And yap, it works now ;)

Now I'm running into another problem I've to figure out. You don't know why an uninvolved Seam component turns to null as soon as I click on upload on a ice:inputFile?