EJB3 entity bean update, best practice

I have an ejb3 entity bean that models a time that can be reserved in a booking system.
I need a way to reserve the time for a specific user. Ofcourse the reservation should not overwrite if the time has already been reserved by another user.
What is the best/cleaneste way to provide this service?
I have thought of the following ways.
I could put a version field on the entity. When the user is set in the frontend the entitybean will check that the time is not already reserved. If not it will be sent backup to the stateless session bean for persisting. If the time has been reserved by another user in the meantime JPA will throw an exception since the version doesn't match any more. The frontend can then show the error to the user.
I could make the frontend call a method in a stateless session bean to reserve the time. The function could take the times primary id and the users primary id and loaded them from persistence. Then check if the time is already reserver else set the user and persist the time again. This should ofcourse be within a transaction and possibly also use a version attribute on the entity.

Only fields detected as persistent-dirty will be updated in the database record.
Laurent

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Will updates to an EJB3 entity bean update ONLY changed columns?

Hello,
If you have an EJB3 entity bean that maps to a table, and then you change the value of ONE of the fields in the entity bean, will each column in the row be updated, OR just the column that changed in the row?
Thanks

Only fields detected as persistent-dirty will be updated in the database record.
Laurent

Ejb3 entity bean not generating valid sql for postgres 8.1

Hello,
I originally posted this on the jboss seam board as I ran across this error on a seam test example, but it seems it's more generally applicable to ejb3 entity beans not generating sql that postgres can understand. I'll post my message below, all replies are appreciated.
I'm going through the hello world example from the seam book, and I'm getting an error I cannot resolve, that with an auto generated sql statement, that's not valid for postgres 8.1, the database I'm on. Here's my error:
17:40:31,370 INFO [STDOUT] Hibernate: select next value for person_id_seq from dual_person_id_seq
17:40:31,394 WARN [JDBCExceptionReporter] SQL Error: 0, SQLState: 42601
17:40:31,394 ERROR [JDBCExceptionReporter] ERROR: syntax error at or near "value"
17:40:31,396 FATAL [application] javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not get next sequence value
javax.faces.el.EvaluationException: javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not get next sequence value
Here's the table definition
- create table Person (id bigint not null, name varchar(255), primary key (id))
- create table dual_person_id_seq (zero integer)
- create sequence person_id_seq start with 1 increment by 1
and here's the entity bean:
@Entity
@Name("person")
@Table(name="person")
@SequenceGenerator(name="person_sequence", sequenceName="person_id_seq")
public class Person implements Serializable {
private long id;
private String name;
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator="person_sequence")
public long getId() { return id;}
public void setId(long id) { this.id = id; }
public String getName() { return name; }
public void setName(String name) { this.name = name; }
How do I get it to generate a valid sql statement for postgres?

I think you should try putting the sequence generator annotation over the primary key field. Try it and be sure it works.
regards,
Michael

JSF CDI : Conversation scope bean[s] best practice

*JSF CDI : Conversation scope bean[s] best practice*
Hello, im currently learning about JSF 2.0 and im so glad for the existence of this conversation scope feature, which is very helpful in opening a new tab or a new window on the same page and having separate resources, not overriding one another.
But im curious on how to implement this in a good way, about when to start the conversation and when to close it.
In my case, i have each CDI bean for each JSF page. And let's say that i have a menu, and when it's clicked, this will lead to page A, and from A, could lead to B, B could lead to C, C could lead to D, all these 4 pages are connected in one chain.
Accessing A's bean properties from B or C or D beans is possible, accessing B's properties is also possible from C or D beans and so forth.
Now im quite confused about :
* whether all these A B C D should be in conversation scope or not, or perhaps just A ? Because i think sometimes from another page that is outside the ABCD chain, like a page F, it could navigate to page B, although i dont know how to supply the data to the bean B yet.
* whether all these A B C D should be combined into one bean
* where and when to start the conversation, im thinking about the constructor, but i dont think it's a good idea, because i prefer starting the conversation when first accessing the page, not the bean
* where and when to stop the conversation, so that there wont be unused resources hanging around
Regards,
Albert Kam

There are also some commandButtons on the view page, which performs actions on Product object, fetched by passed ID.

CMP entity bean update after database update

I'm new to JDeveloper and J2EE. Since JDev 10.1.3 is now production software I finally got started with it. Everything was quite simple to achieve however I have one problem.
My current setup is faily easy. I have a statelss session bean and a CMP entity bean using TopLink (both EJB 2.1). Getting them both created went smooth and having the two talk was as easy as pie thanks to Jdev.
The problem I have is with the entity bean. I'm using a custom finder method to retrieve records using non-PK fields. This works like a charm and I'm getting the data I need. But when I update the data in the database (OracleXE) and I rerun the client I get the old data. The only way for me to get new data is to restart the embedded OC4J server in JDev.
How can I have the entity bean updated by changes in the database?

Thanks Avi!
I spent some time with the documentation and I see I can configure the cache. However how to do this is not clear to me. I have the impression that most of it relates to BMP entity beans.
Apparantly there is a DoNotCheckCache method I can invoke on the query, but I have no idea how to achieve this...
Message was edited by:
Deddiekoel

Does an entity bean update result in ALL DB columns being updated?

Hello,
If I update a single field in my entity bean, will all the columns for the DB row be updated? -OR will only the changed column value be updated?
Thank,
Keith

Only fields detected as persistent-dirty will be updated in the database record.
Laurent

Bean load best practice

I am not new to Java, but up until now have been a programmer. I am now getting more into design and architecture and have a question about best practice. This question arises from a UML class I was taking. But in the class we stayed within the UML and did not get into implementation.
My Question
When creating classes and designing how they interact, what is the best practice for implementing associative relationships. For example, if I were modeling a Barn that contained Animals, I would create a Barn bean and an Animal bean. Since the Barn contained Animals I could create the code like this:
public class Barn {
String color;
Collection animals;
void setColor(String newcolor);
String getColor( );
void setAnimals(Collection newanimals);
Collection getAnimals( );
public class Animals{
String name;
void setName(String newname);
String getName( );
}The Collection within the Barn bean would be made up of Animal beans.
This seems fairly straight forward. However, what if I loaded the bean from a database? When building the bean, do I also find all animals and build the Animal beans and create the Collection to store within the Barn object?
Or
Do I omit the animal Collection from my Barn bean and only populate the Collection at runtime, when someone calls the getAnimals method?
I am confident that the latter is the better design for performance and synchonization issues. But I wanted to get other opinions.
Do I need to read up more on object design?
Thanks,
Lonnie

And lazy initialization. Basically, unless the data is needed. Don't load it.

IOS Update Best Practices for Business Devices

We're trying to figure out some best practices for doing iOS software updates to business devices. Our devices are scattered across 24 hospitals and parts of two states. Going forward there might be hundreds of iOS devices at each facility. Apple has tools for doing this in a smaller setting with a limited network, but to my knowledge, nothing (yet) for a larger implementation. I know configurator can be used to do iOS updates. I found this online:
https://www.youtube.com/watch?v=6QPbZG3e-Uc
I'm thinking the approach to take for the time being would be to have a mobile sync station setup with configurator for use at each facility. The station would be moved throughout the facility to perform updates to the various devices. Thought I'd see if anyone has tried this approach, or has any other ideas for dealing with device software updates. Thanks in advance.

Hi Bonesaw1962,
We've had our staff and students run iOS updates OTA via Settings -> Software Update. In the past, we put a DNS block on Apple's update servers to prevent users from updating iOS (like last fall when iOS 7 was first released). By blocking mesu.apple com, the iPads weren't able to check for or install any iOS software updates. We waited until iOS 7.0.3 was released before we removed the block to mesu.apple.com at which point we told users if they wanted to update to iOS 7 they could do so OTA. We used our MDM to run reports periodically to see how many people updated to iOS 7 and how many stayed on iOS 6. As time went on, just about everyone updated on their own.
If you go this route (depending on the number of devices you have), you may want to take a look at Caching Server 2 to help with the network load https://www.apple.com/osx/server/features/#caching-server . From Apple's website, "When a user on your network downloads new software from Apple, a copy is automatically stored on your server. So the next time other users on your network update or download that same software, they actually access it from inside the network."
I wish there was a way for MDMs to manage iOS updates, but unfortunately Apple hasn't made this feature available to MDM providers. I've given this feedback to our Apple SE, but haven't heard if it is being considered or not. Keeping fingers crossed.
Hope this helps. Let us know what you decide on and keep us posted on the progress. Good luck!!
~Joe

Exchnage sp1 to sp3 Update Best Practices?

Can someone outline Patching Best Practices?
I need to upgrade Exchnage 2010 sp1 to sp3 for my potential customer?-There are Few questions in my mind
-How do i proceed with Multi site Deployment , can i patch all CAS, MBx and Edge servers for site A and then move to site 2?
-What are things that must be taken care of while performing whole process? -I've theoretical overview of how to proceed with the Upgrade, Just wanted to make sure if
there is anything else that needs to be taken care of before performing this to production environments?
Thanks in Advance.

Hi,
In addition to Will Martin's suggestion, I would like to verify if there is a DAG in your environment. If yes, please follow the steps below to upgrade it.
1. Run the StartDagServerMaintenance.ps1 script to put the DAG member into maintenance mode and prepare it for the update rollup installation.
2. Install the update rollup.
3. Run the StopDagServerMaintenance.ps1 script to take the DAG member out of maintenance mode and put it back into production.
4. Optionally rebalance the DAG by using the RedistributeActiveDatabases.ps1 script.
Hope this can be helpful to you.
Best regards,
Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact [email protected]
Amy Wang
TechNet Community Support

Managed bean inheritance best practice

Hi!
I'm new to JSF so I would like to apologize if my question is trivial, but I haven't been able to find proper solution.
I'm using JSF 1.2 on WAS CE. I have a page where user can search for some entities, both person and company, which share some data, but have some different properties. Both inherit from entity class, so search results are displayed in dataTable as base entity objects. Each dataTable row has commandLink which should navigate user to specific (person or company) page for editing data. For example, if user clicks on commandLink in person data row, I would like to show personEdit page with all data set to components. I understand that I can use action to set navigation to proper page, and I have done so (following action() method). I have implemented EntityBean, PersonBean and CompanyBean:
public class EntityBean {
    protected Entity entity;
    public int getId() {
        return entity.getId();
    public void setId(int id) {
        entity.setId(id);
    public String action() {
        // Some code which defines return value for action invoking.
    public void edit(ActionEvent event) {
        // Get entity data for edit.
public class PersonBean extends EntityBean {
    public String getFirstName() {
        return ((Person)entity).getFirstName();
public class CompanyBean extends EntityBean {
    public String getName() {
        return ((Company)entity).getName();
}I tried combining action with actionListener method (+edit(ActionEvent event)+ method) invoked from commandLink, but if it is invoked on mapped entityBean, I get only entity properties set on any other page which is shown after invoked action. If method is invoked on i.e. personBean (same method, not overriden), I get NullPointerException for trying to access property for base entityBean.
How should I invoke proper data initialization for bean shown on another page?
Thanks in advance.

Thank you for your quick reply. Beside the code for managed bean classes, here's the rest of the code for this specific problem.
In faces-config.xml I have the following configuration:
     <managed-bean>
          <managed-bean-name>entitySearchBean</managed-bean-name>
          <managed-bean-class>entities.EntitySearchBean</managed-bean-class>
          <managed-bean-scope>request</managed-bean-scope>
     </managed-bean>
     <managed-bean>
          <managed-bean-name>personBean</managed-bean-name>
          <managed-bean-class>entities.PersonBean</managed-bean-class>
          <managed-bean-scope>request</managed-bean-scope>
     </managed-bean>
     <managed-bean>
          <managed-bean-name>entityBean</managed-bean-name>
          <managed-bean-class>legalentities.EntityBean</managed-bean-class>
          <managed-bean-scope>request</managed-bean-scope>
     </managed-bean>On my JSP, I have a dataTable loaded with entityBean objects, and the following code for showing editPage:
     <h:column>
          <h:commandLink id="editLink" action="#{entitySearchBean.editEntity}" actionListener="#{entityBean.edit}">
               <h:outputText value="#{bundle.edit}" />
               <f:param id="editId" name="editId" value="#{entity.id}" />
          </h:commandLink>
     </h:column>
</h:dataTable>So, what I'm trying to do is to call entityBean.edit which should initialize EntityBean with entity data, and it sets i.e. person data to entity field of EntityBean class. I also call editEntity method on EntitySearchBean class (bean used just for searching entities with some criteria), and pass id property of selected entity in dataTable.
What I'm expecting is to get personEdit.jsp with loaded personBean data initialized from actionListener on searchPage.jsp. Is it possible or is there some other way to do this?

Update Hierarchy Acrobat 9.x/Update Best Practices?

Because of the many problems with Acrobat that seem to be caused by updates, I find it is common that I have to reinstall Acrobat (we are using 9) on someones machine.
Our installer disc/files are Acrobat 9, missing of course all the updates. I typically run the updates seperately as I have them already downloaded...but I have been going in each step (9.12, 9.13, 9.14, etc.) which takes forever. By my count, I have 14 updates that need installed one by one after I install Acrobat. This is very time consuming.
Is there any idea or list of what updates I can skip b/c their fixes are included in the next release? Or, better yet is there a way that I can download a full installer of 9.4.4 or w/e is current that works with my 9.x activation keys?
Wondering what other system admins do with the growing updates for this application.

how would one create an installer as you mentioned? I created a batch file to install each update silently one at a time, but it is still a pain b/c if you don't disable UAC, you sit there and press continue every time...not ideal for widespread use.

JDBC / SQL Update Best Practice

My application updates a database table whenever a user modifies their profile.
I have two questions on this...
1. I've chosen to use PreparedStatements purely because it means I don't have to worry about special characters (e.g. '%"? in my data), and not because I re-use the statements. Is this a respected approach?
2. Is it worth dynamcially building the update SQL and adding paramaters because in most cases only a subset of the possible fields will be modified? (e.g. avoid setting col1="test" if col1 already equals "test"). Is there an acknowledged pattern / algorithm / library that does this?
Thanks,
Steve

My application updates a database table whenever a
user modifies their profile.
I have two questions on this...
1. I've chosen to use PreparedStatements purely
because it means I don't have to worry about special
characters (e.g. '%"? in my data), and not because I
re-use the statements. Is this a respected approach?Yes.
>
2. Is it worth dynamcially building the update SQL
and adding paramaters because in most cases only a
subset of the possible fields will be modified? Probably not. The only time this is going to matter is if there is a significantly sized field (like a blob) that often does not get updated. In that case you would probably want to exclude that.
(e.g. avoid setting col1="test" if col1 already equals
"test"). Is there an acknowledged pattern / algorithm
/ library that does this?Officially not as far as I know.
There are several patterns that I have used.
1. A modified flag for each field. If the set method is called then the flag is set to true.
2. A modified flag for each field. If the set method is called then the new value is compared to the old and the flag is set depending on the outcome.
3. The database layer holds (or retrieves) the previous data. It compares the two, noting the fields that have changed.
In the above note that primary keys must be dealt with. Usually the primary key is either set or not set. If not set then it is a new record. If set then it is an update.

Piloting Software Updates Best Practices

Hello All
I am in the process of configuring our Software Updates infrastructure. My plan is to deploy patch Tuesday updates first to a Pilot Group (Collection) and then to what I will call Production group (Collection). Now when it comes to the pilot phase of software
update testing of course we are just trying to see if any updates may prove problematic. Are there any other extensive testing methods or tips anyone use. Any helpful info would be appreciated.
Thanks,
Phillip
Phil Balderos

Generally, folks let the pilot users know that updates are coming and to do their normal "thing(s)". If there is something business critical, then having them test that would also be prudent. The pilot users should be representative of a broad
cross-section of users to try to catch any issues among all of the various tasks that go on. Getting informed pilot users involved is of course helpful also so that they can provide relevant and pertinent feedback. At the end of the day though, there are no
guarantees so you should stress this management.
Jason | http://blog.configmgrftw.com | @jasonsandys

Error when deploying a simple Entity bean (EJB3) on Glassfich or Sun AS

Hi,
After some problems when deploying complex EJB3 Entity bean on GlassFich with a MySQL connector, I have made a simple entity.
(test with Glassfish and Sun AS with same result)
With netbean 5.5 => New EJB Module
File->New->Persistence Unit (and use default values)
Persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="test" transaction-type="JTA">
   <provider>oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider</provider>
    <jta-data-source>jdbc/sample</jta-data-source>
    <properties>
      <property name="toplink.ddl-generation" value="create-tables"/>
    </properties>
</persistence-unit>
</persistence>File->New->Entity Class
EntityTest.java
package test;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class EntityTest implements Serializable
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    /** Creates a new instance of EntityTest */
    public EntityTest()
    public Long getId()
        return id;
    public void setId(Long id)
        this.id = id;
    public String toString()
        //TODO change toString() implementation to return a better display name
        return "" + this.id;
}Build of project work fine but when I try to deploy (with the 2 servers), I have the error :
Exception occured in J2EEC Phase
com.sun.enterprise.deployment.backend.IASDeploymentException: Deployment Error -- null
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:790)
at java.util.HashMap$KeyIterator.next(HashMap.java:823)
at com.sun.enterprise.deployment.backend.EjbModuleDeployer.generatePolicy(EjbModuleDeployer.java:203)
at com.sun.enterprise.deployment.backend.ModuleDeployer.doRequestFinish(ModuleDeployer.java:171)
at com.sun.enterprise.deployment.phasing.J2EECPhase.runPhase(J2EECPhase.java:169)
at com.sun.enterprise.deployment.phasing.DeploymentPhase.executePhase(DeploymentPhase.java:95)
at com.sun.enterprise.deployment.phasing.PEDeploymentService.executePhases(PEDeploymentService.java:871)
at com.sun.enterprise.deployment.phasing.PEDeploymentService.deploy(PEDeploymentService.java:266)
at com.sun.enterprise.deployment.phasing.PEDeploymentService.deploy(PEDeploymentService.java:739)
at com.sun.enterprise.management.deploy.DeployThread.deploy(DeployThread.java:174)
at com.sun.enterprise.management.deploy.DeployThread.run(DeployThread.java:210)

Yes, the problem is that the ejb-jar must contain at least one ejb component. It's a common misconception that Java Persistence API Entity classes are ejb components but they are NOT. The Java Persistence API was developed within the EJB 3.0 JSR and works very well with EJB but the entity classes themselves are not full-fledged ejb components.
--ken

Creating entity beans (EJB3) from xml schema

Dear friends,
I have a XML schema.. and I want to implement an Enterprise application with EJB3 Entity Beans exposed through a set of JAX-WS Web-Services...
question: how to define the entities from the XML schema?

Two alternatives:
1) JAXB 2.0 generates POJOs with JAXB annotations in them. You can take ownership of those POJOs and add Java Persistence API annotations in them by hand. Basically, you will end up having both both JPA and JAXB annotations in the same Java class. You can then use them in your code both with JAXB APIs and JPA APIs.
2) Have a look at http://hyperjaxb3.dev.java.net/ It is trying to automate what I described in #1. The project is still not complete, so right now, you may have to hand code the JPA annotations.
Sahoo

EJB3 entity bean update, best practice

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