Articles

RMOUG Training Days 2012

Java Hair Owner — Mon, 13 Feb 2012 19:52:24 +0000

I will be co-presenting at RMOUG Training Days with Jigar Parsana on the topic of modernizing Oracle Forms to a Struts 2 / Spring / Hibernate solution. We will present a case study and a comparison between this "open" framework and Oracle's ADF framework.

If you are going to be at RMOUG Training Days, be sure to come by Room 401 on Thursday, February 16th at 2:45.

Another JBO-25030 Problem

Java Hair Owner — Mon, 29 Aug 2011 18:34:56 +0000

Chris Muir has a good article explaining a typical JBO-25030: Failed to find or invalidate owning entity problem. Recently, however, I came across another atypical reason for the same error.

In this particular instance, converting the logic from an exisitng form to an ADF application, there was a master-detail relationship on the page. When the user created a new master record and then attempted to create a new detail record, the JBO-25030 exception would be thrown. What I found when investigating this was that if the user saved the master record first, then added a detail record, everything would work as expected.

Investigating further revealed that there was a primary key on the master record that was not updateable by the user. It was generated by a trigger on the database table. Since the primary key could not be validated when the child record was to be created, the exception was thrown.

This type of issue is easily overcome by putting the logic to get the new primary key (in this case from a sequence) in the ADF Code and removing the table's trigger.

Google admits I was right, buys Motorola

Java Hair Owner — Wed, 17 Aug 2011 18:11:54 +0000

Ok, so maybe a little hyperbole in the headline, but Google may have admitted that Apple, at least, had it right. A lot has been said about the Motorola purchase and it's implications for the bubbling patent wars but could this purchase represent more than that?

My last post in this area was about how Apple beat Oracle and Google, referring to their control over the hardware and the software in their business. It now appears that Google agrees and decided to do something about the situation by purchasing Motorola.

While some articles have pointed out that Google is both alienating it’s friends, and bolstering it’s enemies, others have pointed out that this gives Google the control it needs to make Android a success. Hopefully this will give them a hardware platform that can keep up with releases of the software and provide a consistent less bug-prone environment for Android to shine in. If this alienates some previously Android friendly companies such as Samsung and Sony, so be it, it may just help them keep up with Apple.

Of course the mobile platform is just one industry that Google will now have a hardware presence in. Motorola does produce a great many cable boxes which means Google TV may have found a new platform to shine on as well. While I love my Tivo, I am curious to see what Google may do in this arena in the future.

I should mention, in regards to my last article, that though Sun did provide the hardware platform and the software for Java to grow, they never had any kind of pull in the desktop arena, though they did try. Sun and Java did become a very popular combination for supporting web applications. Oracle has also pointed out that one of their reasons behind the Sun purchase was to provide a hardware platform to support their database. The Exadata hardware/software combination is a great example of this ability Oracle now has to control the entire environment.

The trends certainly seem to indicate that while open specifications and standards are great in some areas, it is easier to move forward when both the hardware and software can work together closely.

ADF 11g - Using LOV's for Convenience, not Validation

Java Hair Owner — Thu, 11 Aug 2011 16:06:14 +0000

In an existing Oracle Forms application we are modernizing for a customer, the forms in places contain LOV’s that exist on the field for convenience, but not for validation. That is, a user can select an item from the LOV or they can enter text. The text they enter will not get added to the table referenced in the LOV, just the current data entry record.

When you create an LOV on an attribute in ADF 11g you can tell ADF what type of control to use. For this type of control we want an Input Text with List Of Values. This control will then be placed on the jsp page when you drag and drop the attribute from your Data Controls panel. When it creates the control, it will also create a validator for the control, JDeveloper actually does this for all controls and it allows for immediate feedback when a mandatory field is not entered or the type of data does not fit the specified format, or in this case, the entered data does not match a value in the LOV list. In order to allow the user to enter a value not in the list, you need to remove the validator.

In our case, this has the benefit of looking up a description and displaying it in another field when a existing value in entered. If an existing value is not entered, nothing is displayed in the description field.

Why Apple has won and Oracle and Google have lost

Java Hair Owner — Mon, 20 Jun 2011 20:57:05 +0000

Working in the field of software modernization and being specifically focused a lot of the time on modernizing client/server applications, that is, bringing native applications to the web, I couldn't help but wonder if we haven't come full circle already.

Many years ago with Sun's release of Java as the write-once, run anywhere answer to every developer's problems, it looked like Java Applets might be the wave of the future. That never did quite catch on as Sun had hoped. It was plagued mainly by the practical problem of having a platform that runs on every operating system in the same if not very similar fashion. Because of this "feature", the platform could be limiting at times. I believe that this type of limitation and the advance of dynamic HTML, CSS, and the web platform in general led to a huge number of web-based applications and a very small number of Java client applications.

Fast forward from then to now and Apple has taken a lesson from Java and decided early on to do things the "right" way. Of course, the "right" way means being in control of the hardware platform as well as the software platform. Because Apple controls the whole environment, "apps" are less likely to break, testing is simplified quite a bit, and even development to some extent is simplified. The result is the creation of some truly amazing client applications for consumers.

Google's Android is a player, but it is starting to suffer from what Java suffered from. I am not an Android user, but I have seen the complaints that some applications are only supported by newer versions of the software but some hardware platforms do not support the newer version. This comes across as an Android problem, but surely Apple has the same problem with their platforms?

For some reason, when I can't get an App for my iphone 3G because it doesn't sport the right hardware, it feels like MY problem for being 3 years behind the technology. That's probably because it isn't just a hardware compatibility issue, the device itself feels clunky and dated compared to newer versions of the iPhone. Android hardware is so varied and different that the same comparison really cannot be made unless it is among one manufacturer.

Anyway, my point is that Apple has created this beautiful sandbox where these great apps can be created that use the web, but are not web applications. They are client/server applications with the server being multi-tiered now. Just look at the articles that have come out regarding iCloud and the amount of app traffic vs. web traffic. iOS is really what Java should have been.

We haven't seen the push at the Enterprise level yet. Most customers want a web application, a more and more sophisticated web application, but still, not native apps. More and more, however, companies are looking at iPads as tools for their workforce and once that happens, their new apps are going to be native iOS apps.

Now the big question remaining is what is Oracle going to do about it? Does Java have a chance or has it's time passed?

Things I learned at UKOUG 2010

Java Hair Owner — Wed, 08 Dec 2010 16:55:59 +0000

This year's UKOUG was a really interesting event. There was a stream dedicated to development and most of the presentations were pretty good. What I liked most about it was that even in the sessions I sat through that covered subjects I was already familiar with, I found I learned a new tidbit here or there.

In the Dynamic Forms and Tables in ADF presentation I learned that you can create a basically empty ViewObject (by basing in on something as inane as "select 1 from dual", and then in your Application Module you can create whatever query you want by using the createViewObjectFromSQLStatement method and passing in your SQL. This is a clever idea and I can see some use for it, especially in reporting type screens, but currently the implementation is a little limited. You can create a Dynamic Table to display the results, but the table cannot have sorting or filtering enabled, which, for a lot of the ADF applications we build, would make those screen noticeably different than other screens.

In a presentation about developing products I learned that Oracle MDS can be used to hold customized information for a specific implementation of an application. That is a very useful feature for ISVs.

A presentation about Javascript in ADF taught me that if you want to use it, you should manipulate the UI Component Model and not the DOM or the "Peer Objects" that would also be available but may not staty consistent.

Finally, in addition to learning that a new utility for creating custom skins is being developed, I learned that if I put a parameter called "DISABLE_CONTENT_COMPRESSION" in my web.xml and set it's value to "true", Firebug would be much more useful in helping to create skins.

One of the most important things I learned is that some things you just don't find out unless you attend these conferences. You could spend your entire career with a product like JDeveloper and not know all the tricks, especially the undocumented ones, but one trip to a conference like UKOUG and you could at least pick up a few of them.

ADF Patterns for Forms Conversions

Java Hair Owner — Fri, 29 Oct 2010 15:53:46 +0000

My presentation: ADF Patterns for Forms Conversions got accepted at UKOUG for this year. I will presenting there on that topic on November 30th at 12:00. Here is the abstract. I hope to see you there!

In the past I have done presentations on why converting to ADF is a good idea. This time I will be focusing less on the why and more on the how so it is bound to be a more interesting presentation for those who are actual Forms or even ADF developers.

Welcome to the new Java Hair site!

Java Hair Owner — Mon, 19 Apr 2010 18:25:31 +0000

We have had our share of technical difficulties in running the blog site, espcially without resources solely devoted to the the updating and running of the server. To deal with that and to be able to post some new content, we have moved the Java-Hair blog to Squarespace.

One of our staffers will be re-posting the content from the old blog up here on the new site, so you will be sure to see a lot of recycled content in the coming weeks, but after that, we'll be on to the new stuff.

So with our technical issues now behind us, we will continue to delight and enlighten you with our vast knowledge of Java, ADF, XML and other enterprise technologies! Be sure to visit frequently and comment often!

Generate an Java-based Ajax-enabled Web App in 5 Minutes

Julia Yiznitsky — Tue, 23 Jun 2009 17:46:00 +0000

Over the last couple of years there has been a lot of talk about Ruby on Rails and Grails and how easy it is to use them to quickly build an application. How would you like to be able to have all of that speed of development, but have it in a technology that you already know? If you are familiar with Struts or JSF, you can use Rev to quickly build an application for you.

Rev is a code generation tool developed by Vgo Software, and it gives you the power to do that. All you need is a database, a JDBC driver (most of the common ones are provided with Rev out of the box), a JDK of version 1.5 or better and Rev. Using Rev you’ll be able to generate a completely functional CRUD application based on the tables that you select. The output can be in a variety of different flavors: JSF, Struts, JSF with AJAX, JDBC, EJB, Hibernate, etc. Rev also generates ANT build scripts for a variety of popular application servers so you can build and deploy your application directly from the tool.

What good is a CRUD application? It all depends on what type of application you are building. For adding testing data or building some Administration screens for a system, the Rev output may be all you need. If you are building a more complicated system, then maybe the persistence layer is all you need and you can rework most of the UI layer. All of the source code is available for you to modify as you see fit, so whether it is the final application itself or the basis for something bigger you will always have something to start with.

One of the unique features of Rev is the ability to customize the generation. Not only can you easily customize the stylesheet from within Rev, but if you want to go deeper you can customize the templates that Rev uses to generate virtually whatever you’d like. From modifying the JSP pages that get generated to creating a whole new set of templates for a completely different language, you can do it all! In fact, included with Rev is a set of templates for generating a PHP-based application.

You can download your free trial of Rev at the Vgo Software site. Also, be sure to sign up for the webinar I will be presenting on June 30th at 11:00 a.m. EST. During that webinar I will demonstrate how to use Rev and talk about the various output options.

Book Review: Processing XML documents with Oracle JDeveloper 11g

Julia Yiznitsky — Mon, 01 Jun 2009 17:31:00 +0000

This is a new feature here on Java Hair, a book review. I was recently approached by the publisher of this book who asked if I would be interested in doing a review. The request was quite timely, I thought, since I have recently been working with XML Schema design (check out the XML category).

“Processing XML documents with Oracle JDeveloper 11g” seems more like the title to a whitepaper than a full-fledged book, but I found that the book actually covers a lot of topics that fall under the XML Processing umbrella. That, and the fact that JDeveloper documentation can be difficult to come by makes this book a pretty handy addition to your library if you develop with JDeveloper 11g and you are working with XML.

Starting out, the book covers the parsing of XML documents using both the SAX API and the DOM API. Information that you could get elsewhere, but as the book is JDeveloper 11g specific, it also includes information on how to set up your projects and which libraries you need to include that may or may not be included with your JDeveloper distribution. Very handy information for someone using JDeveloper.

There is a chapter on using JDeveloper to design an XML Schema, something I could have used a few months ago, actually. JDeveloper’s visual design feature for XML Schema’s is a great tool and comparable to anything I’ve used with Eclipse and NetBeans. Following that is a chapter on validating your schema 3 different ways and how to create these projects in JDeveloper.

There are some chapters that I didn’t expect to see in this book, but were quite welcome. A chapter devoted to transforming XML to PDF, another on transforming XML to MS Excel, storing XML in Oracle Berkeley DB XML, and even a chapter on Oracle XML Publisher.

So all in all, despite the self-imposed limitation of XML and JDeveloper, the author, Deepak Vohra, has managed to cram in some very useful topics into his book. Though some of it isn’t really JDeveloper specific, he does makes it relevant by walking thru setting up each project in JDeveloper as well as building and running the subsequent applications in JDeveloper.

The writing style is very dry, much like you’d probably expect from a reference book, and it should be treated as such, it isn’t something that you are going to want to sit down and read in one sitting. However, if you have work to do in XML and you are considering using or already using JDeveloper as your IDE, I would definitely recommend picking it up.

You can find the book on virtually any online bookstore or on the publisher’s website: Packt Publishing.