jpa spec jsr 317

open jpa manual

In an applicationserver, EntityManager instances are typically injected, rendering the EntityManagerFactory unnecessary.

javax.persistence:

• Persistence : contains static helper methods to obtain EntityManagerFactory
  instances in a vendor-neutral fashion.
• EntityManagerFactory: is a factory for Entity-Manager
• EntityManager: is the primary JPA interface used by applications.Each EntityManager manages a set of persistent objects, and has APIs to insert new objects and delete existing ones. EntityManagers also act as factories for Query instances.
• Entity: persistent objects that represent datastore records.
• Query: Query interface is implemented by each JPA vendor to find persistent objects that
  meet certain criteria. JPA standardizes support for queries using both the Java Persistence Query Language (JPQL) and the Structured Query Language (SQL). You obtain Query instances from an EntityManager.

JPA uses a version field in your entities to detect concurrent modifications to the same datastore record. When the JPA runtime detects an attempt to concurrently modify the same record, it throws an exception to the transaction attempting to commit last. This prevents overwriting the previous commit with stale data.

private int version;

JPA introduces another form of object identity, called entity identity or persistent identity. Entity identity tests whether two persistent objects represent the same state in the datastore.

In this post I will cover getting started with the Roller4.0 blogging software including setting up the planet (aggregation server).

Anyway, I am using the mysql database (5.0.41 community edition) with roller 4
(best available) which i placed in Tomcat’s webapps directory naming the folder roller4_0 .

I am using tomcat 5.5 with java5.

Setup: Tomcat’s common/classes folder have placed file roller-custom.properties:
installation.type=auto
database.configurationType=jdbc
database.jdbc.driverClass=com.mysql.jdbc.Driver
database.jdbc.connectionURL=jdbc:mysql://localhost:3306/rollerdb
database.jdbc.username=root
database.jdbc.password=admin
mail.configurationType=properties
mail.hostname=smtp-server.nc.rr.com
mail.username=x
mail.password=x

Important: You need to put the mysql driver, and two other jars into Tomcats’s common/lib directory:

• mysql-connector-java-3.1.13-bin
• activation (obtained from my java 5 lib folder)
• mail (obtained from my java 5 lib folder)

After starting Tomcat, I go to the main screen via url http://localhost:8080/roller4_0/index.jsp

which says I have a successful connection but have no tables . So I click the button to create the tables.

Then, I get the page to create users and the blog.

Yes, you need a planet-custom properties (roller-custom.properties in common/classes) file…

I set up a blog which i called planet which I give a theme of
roller front page…

My weblog template now has
## 1) SITE-WIDE entries (the default)
##set($pager = $site.getWeblogEntriesPager($since, $maxResults))

One of the struts 2 sample applications is the Mailreader application which has training course via Struts from Square One site .

Building Web Applications
Building Struts 2 Applications [ Welcome] [More ...]

Struts 2 components

Action Handler, Result Handler, Custom Tags

Interceptor : bring custom code into call stack

• Timer Interceptor
• Prepare (able) - If the Action implements Preparable, calls its prepare method.

value stack : stack of objects that expression language can pull from

• Action instance pushed onto stack

Jumpstarting JUnit (More …)

Capturing Input(More …)

Validating Input (More …)

Request Lifecycle in Struts 2 applications

• User Sends request: User sends a request to the server for some resource.
• FilterDispatcher determines the appropriate action: The FilterDispatcher looks at the request and then determines the appropriate Action.
• Interceptors are applied: Interceptors configured for applying the common functionalities such as workflow, validation, file upload etc. are automatically applied to the request.
• Execution of Action: Then the action method is executed to perform the database related operations like storing or retrieving the data from database.
• Output rendering: Then the Result render the output.
• Return of Request: Then the request returns through the interceptors in the reverse order. The returning request allows us to perform the clean-up or additional processing.

Display the result to user: Finally the control is returned to the servlet container, which sends the output to the user browser.
Struts 2 Big Picture

The diagram depicts the architecture of Struts 2 Framework. It shows the the initial request goes to the Servlet container, which is then passed through a standard filer chain.

1. ActionContextCleanUp filter: The ActionContextCleanUp filter is optional. It is useful when integrating other technologies such as SiteMesh Plugin.
2. FilterDispatcher: the required FilterDispatcher is called, which in turn consults the ActionMapper to determine if the request should invoke an action. If the ActionMapper determines that an Action should be invoked, the FilterDispatcher delegates control to the ActionProxy.
3. ActionProxy: The ActionProxy consults the Configuration Files manager, which is initialized via the struts.xml file. Then the ActionProxy creates an ActionInvocation, which implements the command pattern. The ActionInvocation process invokes the Interceptors (if configured) and then invokes the action.
4. Once the Action returns, the ActionInvocation is responsible for looking up the proper result associated with the Action result code mapped in struts.xml. The result is then executed, which often (but not always, as is the case for Action Chaining) involves a template written in JSP or FreeMarker to be rendered. While rendering, the templates can use the Struts Tags provided by the framework. Some of those components will work with the ActionMapper to render proper URLs for additional requests.
5. Then the Interceptors are executed again in reverse order. Finally the response returns through the filters configured in web.xml file.
6. If the ActionContextCleanUp filter is configured, the FilterDispatcher does not clean the ThreadLocal ActionContext. If the ActionContextCleanUp filter is not present then the FilterDispatcher will cleanup all the ThreadLocals present.

Resources

• converting-struts-2-part1
• converting-struts-2-part2
• Tutorial

If you install the war on an application server (like tomcat ) you can easily run the sample projtect. Here is the struts 201 slides

Th version I have of the application mentions: “For more about the MailReader, including alternate implementations and a set of formal Use Cases, please visit the Struts University MailReader site” .

• MailReader Database Worksheet (Struts University)
• MailReader Object Model (Struts University)
• MailReader Tour (Struts University)
• MailReader Use Cases (Struts University)

The full source code for MailReader is available as svn site, binaries, nightlies

Other Struts2 Trainings include Migrating to Struts2 the and JPA .

REFERENCES:

• http://struts.apache.org/2.x/docs/home.html
• http://struts.apache.org/2.x/docs/core-developers-guide.html
• http://opensource.atlassian.com/confluence/oss/display/STRUTS/Home
• http://cwiki.apache.org/confluence/display/S2WIKI/Home
• http://www.gmjjavadesigns.com/gmjd/entry/struts_2_ajax_tags

Just last week, I learned about what’s new with Roller in 4.0

Thought it was finally time to try my own installation after being a one time user of this Roller platform on JRoller as user on http://www.jroller.com/interjavanet/ . I had forgotten my password over on that blog, and it did not seem to be stright forward on how you get your password reset.

Did I mention that Roller is now on Apache at http://roller.apache.org ?

They have their own wiki now at http://cwiki.apache.org/confluence/display/ROLLER

Anyway, I am using the mysql database (5.0.41 community edition) with roller 4
(apache-roller-src-4.0-rc9) which i placed in Tomcat’s webapps directory naming the folder roller4_0 .

I am using tomcat 5.5 with java5.

Setup: Tomcat’s common/classes folder have placed file roller-custom.properties:
installation.type=auto
database.configurationType=jdbc
database.jdbc.driverClass=com.mysql.jdbc.Driver
database.jdbc.connectionURL=jdbc:mysql://localhost:3306/rollerdb
database.jdbc.username=root
database.jdbc.password=admin
mail.configurationType=properties
mail.hostname=smtp-server.nc.rr.com
mail.username=x
mail.password=x

Important: You need to put the mysql driver, and two other jars into Tomcats’s common/lib directory:

• mysql-connector-java-3.1.13-bin
• activation (obtained from my java 5 lib folder)
• mail (obtained from my java 5 lib folder)

AFter starting Tomcat, I go to the main screen via url http://localhost:8080/roller4_0/index.jsp

which says I have a successful connection but have no tables . So I click the button to create the tables.

Then, I get the page to create users and the blog.

References :

• The Roller source code wiki page
• The Roller Build Guide wiki page
• The Roller Install Guide wiki page

Just noticed that Dave Johnson has upgraded Roller in version 4.o to use Struts2 and OpenJPA.

After learning about Webwork last year, I played with using Struts2 examples in a 1.4.x environment.

Roller wiki

Install Guide

• http://www.rkcole.com/articles/struts/crudTutorial/
• http://techienet.org/book-page/sarath/struts2-step-step-guide-programmers
• http://ahmadshajee.blogspot.com/2007/09/struts2-part-i-introduction.html
• http://j2eefolks.blogspot.com/2007/04/struts-2-features-and-short-summary.html

Last week was the conference, this week comes people trying to define it. My best definition would be netvibes.com

A checkpoint on Web 2.0 in the enterprise

As such, the situational application would be another web 2.0 concept. this article defines it great.

“where small groups and departments developed their own applications independent of the corporate IT department. Today more and more end users who are not professional programmers are developing web applications that better fit their own needs. A simple example is a wiki, where the users can create and modify the pages and their content. No programmer has to decide ahead of time what the topics of interest will be or the structure and layout of the pages. The users evolve something over time that suites their needs within the time budget they have to invest in the site.”

REST is another buzzwodr like this slide presentation that explains it.

In Raleigh, I got a chance to attend IBM’s technical briefing on web 2.0 .

For now, will just list various bits of info that I will organize later.

QEDWiki (Quick and easy design) . Assembly : “QEDWiki is a unique Wiki framework in that it provides both Web users and developers with a single Web application framework for hosting and developing a broad range of Web 2.0 applications.”

Damia . Feeds: “provides easy-to-use tools that developers and IT users alike can use to quickly assemble data feeds from the Internet and a variety of enterprise data sources. The benefits of this service include the ability to aggregate and transform a wide variety of data or content feeds, which can be used in enterprise mashups.”

Mashup Hub. Tag : “Mashup Hub provides two broad areas of support: feed generation for enterprise data sources and a catalog of feeds and user interface (UI) widgets.”

Info 2.0

Many eyes

Baby name wizard

gather.com

second life

strike iron

gold corp

zoho

zoot

what is dojo?

Dojo is an Open Source JavaScript UI toolkit. It makes writing JavaScript easier, building great interfaces faster, and deploying dynamic UIs at scale much easier. The foundation of Dojo is “Dojo Base”, a single tiny library which contains Ajax, event handling, effects, blazing fast CSS queries, language utilities, and a lot more. On top of this Base, the rest of Dojo Core adds high-quality facilities for Drag and Drop, extended forms of Ajax and I/O, JSON-RPC, internationalization, and back-button handling.

You can use the div tag to define widget locations and Dojo will place the widget there either during page load or in response to events.

dojo book 0.4 –API — reference documentation — Dojo jot wiki — dojo toolkit home

JavaPassion PDF has 86 pages of info.

What is JSON?

(Using Dojo and JSON to Build Ajax Applications article ) - JSON is a Java library that helps convert Java objects into a string representation. This string, when eval()ed in JavaScript, produces an array that contains all of the information that the Java object contained. JSONObject class , JSONArray class “- Dojo provides an abstraction layer for invoking JSON-RPC requests”

json over xml?

IBM Paper: “JSON is built on two structures:

1. A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
2. An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence

JSON-RPC is a lightweight remote procedure call protocol in which JSON serializes requests and responses

The request is a single object with three properties:

• method - A string containing the name of the method to be invoked.
• params - An array of objects to pass as arguments to the method.
• id - The request ID. This can be of any type. It is used to match the response with the request that it is replying to.

When the method invocation completes, the service must reply with a response. The response is a single object with three properties:

• result - The object that was returned by the invoked method. This must be null, in case there was an error invoking the method.
• error - An error object if there was an error invoking the method. It must be null, if there was no error.
• id - This must be the same ID as the request it is responding to.

A notification is a special request that does not have a response. It has the same properties as the request object with one exception:

id - Must be null“

Using Dojo and JSON to Build Ajax Applications article: Dojo libraries are organized in packages just like Java code. For this example, we will need to import two packages.

The dojo.io package contains classes that allow us to make HTTP requests using protocols such as XMLHTTPTransport.

The dojo.event package is designed to provide a unified event system for DOM and programmatic events.

The dojo.event.connect() method allows you to associate a handler for the onclick event for myButton:

function onLoad() {

   var buttonObj = document.getElementById("myButton");

   dojo.event.connect(buttonObj, “onclick”,

          this, “onclick_myButton”);

  }  function onclick_myButton() {

   var bindArgs = {

    url: “welcome.jsp”,

    error: function(type, data, evt){

     alert(”An error occurred.”);

    },

    load: function(type, data, evt){

     alert(data);

    },

    mimetype: “text/plain”,

    formNode: document.getElementById(”myForm”)

   };

   dojo.io.bind(bindArgs);

  }

The magical dojo.io.bind() function is where the power lies. It takes as argument bindArgs, an array of name/value pairs. In this example, we specify five pairs:

1. url: The URL to make the request to.
2. mimetype: The response type expected.
3. load: Code to execute upon success.
4. error: Code to execute upon error.
5. formNode: The ID of the form whose fields to submit as parameters to the URL.

Once the call to dojo.io.bind(bindArgs) is made,depending on whether the request encountered any errors, either the load or error code is executed. Both load and error take three arguments:
type: The type of function; it will always be set to load for load() and error for error().
data: The response received. If mimetype is specified as text/plain, data contains the raw response. If, however, text/json is used, data contains the value of eval('(' + responseReceived + ')'), where responseReceived is what the call returned.

evt: The event object.

• Dojo with a struts action example
• http://dojotoolkit.org/search/node/tree
• http://willcode4beer.com/ware.jsp?set=dojoTreeWidget
• http://www.sauter-online.de/dojo/demos/widget/Tree/tree.html
• http://www.thearcmind.com/confluence/display/RandomThoughts/DOJO+First+Glance
  
• http://dojo.jot.com/WikiHome/Tree
• http://home.exetel.com.au/cweatures/combosample/combotest.html
• http://www.stack.be/~roel/blog/archives/the-dojo-tree-control-for-beginners-part-1/
• http://www.stack.be/~roel/blog/archives/the-dojo-tree-control-for-beginners-part-2/
• http://www.it-eye.nl/weblog/2007/05/02/use-ajax-treecompontent-in-jsp-with-dojo/

softarc - the anti- experienced Coding Architect

Using NetBeans Open Source Toolbox , and More Netbeans

You are doing more modeling than you think

http://devlicio.us/blogs/derik_whittaker/archive/2007/05/09/questions-every-candidate-should-ask-a-potential-new-employer.aspx

“I am suggesting that there are those around us who are “serial committers” - they always say yes and rarely say no, even when they should.  These individuals become so engulfed by the shear number of commitments that they have made that it becomes impossible for them to execute on any of them, at least not effectively.”

http://cjhemp.wordpress.com/2007/04/28/promise-based-management/

http://drdobbs.com/dept/architect/198000264: “”

AMIS on Deliver valuable software: “Other posts about the AGILE Principles soon to come:
1. Our highest priority is to satisfy the customer through early and continuous delivery of valuable software. (This one).
2. Welcome changing requirements, even late in development. Agile processes harness change for the customer’s competitive advantage.
3. Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
4. Business people and developers must work together daily throughout the project.
5. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.
6. The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
7. Working software is the primary measure of progress.
8. Agile processes promote sustainable development. The sponsors, developers, and users should be able to maintain a constant pace indefinitely.
9. Continuous attention to technical excellence and good design enhances agility.
10. Simplicity–the art of maximizing the amount of work not done–is essential.
11. The best architectures, requirements, and designs emerge from self-organizing teams.
12. At regular intervals, the team reflects on how to become more effective, then tunes and adjusts its behavior accordingly. “

Forget those fancy tools, and try just enough information in requirement gathering.

The Furious Purpose has a good outline on what makes an ideal software job.

• The Team
• The Process
• The Company
• The Product
• The Technology
• The Location (i.e. work at home)

For me, having a software quality plan in place is what you would like to see. Just saw this free (without customizations) for managing the software development process.

Also, collaboration is key for a job where people share knowledge and experiences so that you don’t have to reinvent the wheel everytime. Like this here wiki.

More info On Struts2

Tutorial

I few months back I experimented with Struts2 and WebWorks

and then some…

Here is a wiki entry i created on site.

http://cwiki.apache.org/confluence/display/S2WIKI/Sample+Applications+with+Java+1.4.x

Business Intelliegence Tool  JasperETL - “JasperETL will be available in Open Source and Professional editions, and was developed through a technology partnership with Talend. Led by a team of veteran data integration industry experts, Talend is the first open source software provider for data integration tools.”

ETL is an essential tool that guarantees consistency and fluidity of information in increasingly diverse IT systems. At the center of the decision- making process, ETL allows organizations to move, cleanse, standardize and transform data according to their business needs. JasperETL can be used for both analytic decision support system tasks such as updating data warehouses or marts, as well as for operational solutions such as data consolidation, duplication, synchronization, quality, migration, and change data capture. Performance tests indicate performance up to 50% faster than other leading commercial ETL tools.

JasperETL Open Source edition is available immediately direct from JasperSoft

It seems the video hosting service that AOL uses has a bunch of tecnology based presentations:

• web 2.0
• rails

Technorati Profile

Wow, I am glad to see 2007 here.

As always, New Years Day consists of a lot of  football.

John Edwards announces . That’s a first.

On of the first memories I have from my childhood is  when Nixon stepped down and Ford took the reigns. I did not know about the UNC connection with Gerald Ford til recently. I always heard that Ford was some sort of good athlete.

http://www.castor.org/ and get full download where i placed it here

C:/java/castor-1.0.5

C:\java\castor-1.0.5\src>ant jar

put castor jars from C:\java\castor-1.0.5\dist and place in C:/java/castor-1.0.5/lib

C:/java/castor-1.0.5/src/examples/SourceGenerator

test.bat

http://www.castor.org/javadoc/org/exolab/castor/builder/SourceGeneratorMain.html

%JAVA% -cp %CP% org.exolab.castor.builder.SourceGeneratorMain -i invoice.xsd -f -binding-file bindingInvoice.xml

JavaDoc

Marshalling - is the process of traversing a content tree and
writing an XML document that reflects the tree’s content.
org.exolab.castor.xml.Marshaller
Unmarshalling -  is the process of reading an XML document and constructing a content tree of Java content objects.org.exolab.castor.xml.Unmarshaller

example

…

It has been a while since I got a chance to look at Struts 2 . At the time I was interested in how to get jars going with JDK 1.4.2.