In der aktuellen Ausgabe von Java Aktuell ist der Artikel Single Sourcing mit JVx enthalten. Darin wird anhand eines kurzen Beispiels erklärt, wie der Single Sourcing Mechanismus in JVx umgesetzt wurde. Die Beispiel Anwendung wird als Desktop Anwendung bzw. Web Anwendung gestartet, und das ohne auch nur eine Zeile Source Code zu verändern.

Der Artikel zum Nachlesen: Single Sourcing mit JVx, Java Aktuell Q1-2011

Das Magazin, Java Aktuell, erscheint vierteljährlich und wird vom Interessensverbund der Java User Groups e.V (iJUG) herausgegeben.

We talked with James Sugrue from Javalobby (dzone) about JVx. He had some questions about the framework and we talked with him about the next features.

Read the full interview.

Because of the Plat_Forms competition, we released special versions of JVx, WebUI and OnlineHelp. All releases are available from our project page.

We implemented some amazing new features for JVx and WebUI.

Check out the changelogs for details.

Some tags:

• Simple charting
• Default layouts
• Global metadata caching (server-side)
• Modal frames in WebUI
• Table handling in WebUI

It is available from the project page.

What’s New?

The complete list of changes can be found here.

• Default Database (CoC)It is now possible to configure multiple db datasources via config.xml
  <?xml version="1.0" encoding="UTF-8"?>

  <application>
  <securitymanager>
  <class>com.sibvisions.rad.server.security.DBSecurityManager</class>
  </securitymanager>

  <datasource>
  <db name="default">
  <url>jdbc:oracle:thin:@localhost:1521:mydb</url>
  <username>user</username>
  <password>password</password>
  </db>
  </datasource>
  </application>

  If the DBSecurityManager does not define a specific datasource, the datasource with the name "default" is used.

• Quoting in DBAccessDBAccess supports case sensitive database access. To enable the feature, call
  setQuoting(true);

  on your DBAccess instance.

• Custom SessionManager and ObjectProviderIt was possible to use a custom ObjectProvider but it was not possible to extend the DefaultObjectProvider. Now this limit is gone. Additional it is now possible to use a custom SessionManager and extend the DefaultSessionManager.

  Configure the objects in your server config.xml like this:

  <server>
  <sessionmanager>com.sibvisions.AnotherSessionManager</sessionmanager>
  <objectprovider>com.sibvisions.AnotherObjectProvider</objectprovider>
  <server>
• Server Side TriggersOur DataBooks now supports specific events like before insert or after delete. The server side storage did not have this events, so you had to overwrite the data manipulation methods to call your business logic or to change the default behaviour. That was not very cool.

  We have implemented a very powerful feature, with which you have full control of your data sent to the data tier. Do you know database triggers?
  Now you have the same power in your storages.

  A short example:

  public void getUsers()
  {
  DBStorage dbsUsers = new DBStorage();
  dbsUsers.setDBAccess(getDBAccess());
  dbsUsers.setFromClause("V_USER_USERS");
  dbsUsers.setWritebackTable("USERS");
  dbsUsers.open();

  dbsUsers.eventBeforeInsert().addListener(this, "doEncryptPwd");
  dbsUsers.eventBeforeUpdate().addListener(this, "doEncryptPwd");
  }

  public void doEncryptPwd(StorageEvent pEvent)
  {
  IBean bn = pEvent.getNew();

  bn.put("PASSWORD", AbstractSecurityManager.getEncryptedPassword(
  SessionContext.getCurrentSessionConfig(),
  (String)bn.get("PASSWORD")));

  pEvent.setNew(bn);
  }

  Use the event handling as usual.

• Flat POJO support for StoragesInstead of using the dynamic property access via IBean, it is possible to work with POJOs:
  public void doEncryptPwd(StorageEvent pEvent)
  {
  User user = pEvent.getNew(User.class);

  user.setPassword(AbstractSecurityManager.getEncryptedPassword(
  SessionContext.getCurrentSessionConfig(),
  user.getPassword()));

  pEvent.setNew(user);
  }

  You can work with every useful POJO because the storage mapps only available properties to the POJO.

• Useful bugfixes

We look forward to your reviews

The next beta version is planned for Friday, 7th January 2010. It contains some important bugfixes and improvements for DB handling. The default server implementation supports a custom session manager and object provider. And of course we solved some problems of the previous beta.

Check out our new JVx version. It is available from the project page.

What's in the current beta?

The complete list of changes can be found here.

Some features, however, at this point:

• Introduced DBCredentials and DataSourceHandlerIt is now possible to configure multiple db datasources via config.xml
  <?xml version="1.0" encoding="UTF-8"?>

  <application>
  <securitymanager>
  <class>com.sibvisions.rad.server.security.DBSecurityManager</class>
  <database datasource="mydb" />
  </securitymanager>

  <datasource>
  <db name="mydb">
  <url>jdbc:oracle:thin:@localhost:1521:mydb</url>
  <username>user</username>
  <password>password</password>
  </db>
  <db name="masterdb">
  <url>jdbc:derby://localhost:1527/masterdb</url>
  <username>master</username>
  <password>master</password>
  </db>
  </datasource>
  </application>

  and use the configured security manager connection in the Session:

  IConfiguration config = SessionContext.getCurrentSessionConfig();

  dba = DBAccess.getDBAccess(DBSecurityManager.getCredentials(config));
  dba.open();

  or any connection, by name:

  IConfiguration config = SessionContext.getCurrentSessionConfig();

  DBCredentials cred = DataSourceHandler.createDBCredentials(config, "masterdb");

  dba = DBAccess.getDBAccess(cred);
  dba.open();

  It is still possible to use the old configuration format:

  <?xml version="1.0" encoding="UTF-8"?>

  <application>
  <securitymanager>
  <class>com.sibvisions.rad.server.security.DBSecurityManager</class>
  <database>
  <driver>org.hsqldb.jdbcDriver</driver>
  <url>jdbc:hsqldb:hsql://localhost/demodb</url>
  <username>sa</username>
  <password></password>
  </database>
  </securitymanager>

  You can create DBCredentials or read the config programatically, as it was with JVx 0.8.

• Introduced AbstractCachedStorageThe AbstractCachedStorage is the new base class for all IStorage or ICachedStorage implementations. It implements the metadata caching and offers simple export functionality. With this class it is easy to develop new storages.
• Introduced AbstractMemStorageThe AbstractMemStorage extends the AbstractCachedStorage and offers a MemDataBook on the server-side. With this class it is very simple to create storages with data kept in memory. You don't need a special backend, e.g. you can use a List to fill the storage. Our TwitterStorage uses this storage.
• DBAccess supports pre-configured java.sql.ConnectionCreate a DBAccess instance with a pre-configured connection, e.g.
  Connection con = getJNDIConnection();

  DBAccess.getDBAccess(con)

• XmlNode performance tuningOur XmlNode allows XML access with following syntax:
  XmlWorker xmw = new XmlWorker();
  xmnRead = xmw.read(new FileInputStream("example.xml"));

  xmnRead.setNode("/archive/element(1)/user", "xml");
  xmnRead.setNode("/archive/new/element", "car");

  The class offers powerful and simple XML handling - check it out!

• Bugfixes and Test cases

We look forward to your reviews

We described all DataBook events and row states with some articles in our Forum. The events and states are very important if you need special data/row handling on client side e.g. ask the user before delete record(s).

The articles includes flow charts and practical examples. If anyone has questions, just post to the forum.

Direct links to the events and states.

We have a lot of useful features in JVx. It is very easy to develop multi tier applications, two tier applications or simple desktop applications - started as RIA, Web or Standalone application.
Every tier is technology independent and does not require third party frameworks. We can use every useful framework to create business logic.

But we don't have a lot of connectors out-of-the box (at the moment). There are a lot of technologies out there, e.g. NOSQL, Cloud services, Facebook, Twitter, YouTube, REST, ...

Not all technologies are useful for business apllications, but it is a lot of fun to work with new technologies

We spent some hours to develop a simple Twitter client (rather a connector) to read/delete/insert Tweets. The result can be seen here:

Twitter client with JVx

What we did?

• Created a new Storage, called TwitterStorage
• extended AbstractMemStorage
• Implemented loadData, insert, delete and getRowDefinition
• used twitter4j

After 290 lines of code we were finished. The standard RemoteDataBook works perfect with the new Storage (full support for filtering, sorting, master-detail relations).

The last release of JVx - 0.8 - was published on 11th October. But when is the release date of JVx 0.9 and later?

We defined following release cycles for the upcoming versions:

• GA release cycles of 6 months.
• We don't publish alpha versions/nightly builds.
• Beta versions every month (no fixed intervals). The first beta version of the next release will be available 1 month after the last GA release.
• Developer builds are possible with the source code from our repository (ant build files are included).

For the JVX Release 0.9, this means:

• Next Beta: first week of December (No Beta version for November)
• Next GA release in March/April 2011

This is our current schedule.
We are open for discussions to optimize our approach.

Well, after the version 0.8 of JVx was released, it's time for some LoC statistics.

Particularly the clarity and comprehensibility of the Source Code are very important to us. Therefore we are very proud also of the following lines of code.

Compared to the features, we have too few lines of code
But exactly that makes the difference!