Des Profundis...

Windows Power Shell

2011-11-03T20:35:00.001+01:00

As a linux user, I had always been frustrated that I must use a stupid command line to perform some task under windows. Or even worse, there were a lot of tasks I could even perform like that, because the commandline did not have any grep, find, and similar utilities.

This is until I discovered the powershell. Since I have to use windows at work and sometimes I do not even have the possibilty to use cygwin with suitable tools. I really got frustrated. But now that I looked into many of the power shell language, I must admit that it is quite impressive, what one can do with it. I also find it great that the powershell understands both pipes and objects...

I will probably add here many of the useful features I discovered. In someway I think Microsoft understood that they had to become more competitive in order to keep their customers.

GWT, SmartGWT and Testing

2011-11-03T20:28:00.001+01:00

Automated testing is very useful, and would be even more useful, if it was much more easy. It seems though that the testing frameworks for web application as still not yet part of the tool box of web application developpers.

I hope this will help me to implement automated testing of web application.

I did some research on testing of GWT. It seems that it is possible to use selenium for GWT and for smart gwt. I must really get to this quickly.

CRISP Builds

2011-11-03T20:27:00.000+01:00

For build architectures, it is useful to use a CRISP build:

Complete (recipe lists all ingredients)
Repeatable (version control time machine)
Informative (radiate valuable information)
Schedulable (complete and repeatable)
Portable (machine-independent)

In the latest project for which I worked we use a continuous integration system.
At some point, it can be annoying because we do receive a lot of uninteresting mails.
But once configured it is really good to insure quality and reproducable results.

As a developer, I know how easy it is to deploy something on the server,
which is not exactly what is on the server.

Performance in Java

2011-11-03T20:23:00.002+01:00

For diverse purposes I wanted to take a look at performance benchmarks for diverse implementations of collections.

I came to the following free book: Java Performace Book

Moreover, for a project for which I am working we will be do performance measures in order to choose the best infrastructure
for our project. We will do some profiling using JETM or using JProfiler depending on which gives the best infrastructure for our goal.

Code Generation

2011-03-04T00:14:00.008+01:00

Since my last project, I gained much interest in code generation. The application we were supposed to reimplement using GWT consisted of around 60 entities and had as many dialogs to be implemented. Moreover, the database schema we had was in german. Since we did not want our code to be a mix of English and German, we needed to create a lot of typical classes for this: entities, DAOs, business logic, service layer, controller as well as more or less straight forward dialogs.

Since I did not have any of my usual tools, I decided to create my own generator, which could generate simple (still to be edited!!!) versions of the diverse classes we needed. This went quite well except that I needed to write java code to perform these actions. So the first generation was somewhat of a procedural code generator. This was a tedious task which made it quite difficult to maintain the code in the always evolvin software infrastructure we had.

A more useful approach is template generation. However for templates to be adapted for such a task you need a template language capable of looping over fields and methods of the code model.

Interesting Topics for Code Katas

2011-03-04T00:07:00.005+01:00

Since I discovered about Code Katas (?here link me please?), I played with the question as to know which code kata would be appropriate for me. The following is an extensible list of topics which should be covered by these Katas.

Code katas:

- algorithmic katas
- architecture patterns
+ View architecture pattern
- MVC (Model view controller)
- MVP (Model view presenter)
- Formular Web page
+ JSF
+ GWT
- MVC
- Web Service and Gui library choice
+ RAP
javacript libraries
+ jquery
+ ext.js
+ dojo
Jpa and hibernate
- jpa -> schema
- schema -> jpa
- query jpa
- query plsql
- query criteria
Aspects
- logging
- security
Testing
- Unit Tests
- GUI Testing
- test coverage
Build framework
- ant
- maven
- gradle
frameworks
- spring
- AOP
- MVC
- Web Flow
- Security
- hibernate
- OSGi
- roo
- flex
scm
- git
- server
- svn

Please do not pay attention to the formatting this should be improved soon.

Maven Repository in PHP or Virutal machine for Maven Repository

2010-09-02T21:17:00.003+02:00

Since I would like to put my software in a maven repository, and since it is difficult to find Java/JSP enabled providers in Europe. I was wondering whether I should not try to reimplement the archiva project directory with PHP or perhaps Ruby.

After having a look, it does seem quite a lot of dirty work. But it is probably not too complex to perform. But is it worth it ?

Hosting and Server types

2010-08-30T18:44:00.005+02:00

I have been searching for diverse information lately on Servers and possible hosting of my own stuff. I found the web page: Hotsuche.de. It is a typical site to look for the currently available offers in the hosting and servers.

They present the offers according to the following category, and quite extensive search formular to define the kind of offers one might prefer.

I give here a summary of these categories:

domains
Web hosting
dedicated server
server housing
Buy Server
Virtual server
Game server
Internet access
Shops
SSL Certificates
Test accounts

I discovered the possibility of server housing, i.e you buy a server and you have some company keep it in its computer center. I have to take a look at the prices. But I suppose that this is not cheaper as using a server from the company. You can also have Game servers or buy servers. This sounds also interesting.

Where do I get a cheap Java/JSP Server ?

ac - user connect time

2010-06-10T17:06:00.001+02:00

I just discovered a new command that I did not know: ac. It gives the connect times of users. This may prove useful.

Vendor Lock-In

2010-06-10T14:45:00.002+02:00

Here is an interesting blog entry on vendor lock-in.

It lists three types of vendor lock-ins each based on some component of the application: platform, data or tools.

Postgresql Info Website

2010-06-10T14:19:00.003+02:00

I just discovered this postgresql info website: http://www.postgresonline.com/. I guess I will learn quite a lot from this website.

I learnt that the new version of postgres is nearly out, since the version beta 2 is out. It should not be long before the 9.0 comes out.

It might also be good to follow: http://www.planetpostgresql.org/.

Quo Vadis with Software Patent

2010-05-20T18:34:00.002+02:00

After I read this news, I had to sit: German High court ruled in favor of software patents.. Unfortunately, this is not an April joke. However, the strange thing is that it does seem like there is already a patent for the technology provided, and that even if it should be obvious that the technology described in the patent existed already at the time of the patent submission.

Privacy on Facebook

2010-05-20T10:32:00.004+02:00

Thanks to a friend, I heard about the site: http://www.reclaimprivacy.org. It contains certain useful information on privacy settings onf Facebook. For instance, there is an interesting page on the privacy on facebook (hosted by the New York Times).

In order to check your own privacy on Facebook, you can follow the instructions on the website:

This website provides an independent and open tool for scanning your Facebook privacy settings. The source code and its development will always remain open and transparent.

Note: we are still working on privacy scans for your photos and status updates. The tool does not check these yet, so stay tuned for updates!

1. Drag this link to your web browser bookmarks bar: Scan for Privacy

2. Go to your Facebook privacy settings and then click that bookmark once you are on Facebook.

3. You will see a series of privacy scans that inspect your privacy settings and warn you about settings that might be unexpectedly public.

4. Follow us on Facebook to hear about the latest updates.

New Advances in Neural Networks

2010-05-10T15:26:00.002+02:00

There is a great google talk about recent advances in pattern recognition in Neural Network. It is given by Goeff Hinton. The title of the talk is Recent Developments in Deep Learning.

AXIOM - an Apache Stax Parser

2010-05-06T22:42:00.002+02:00

I will have to take a look at Axiom which provides a Stax implementation to access XML info sets. It was developed for Axis 2. But it can be used independantly.

Apache Tika - Content and Metadata Extraction in Java

2010-05-06T15:15:00.003+02:00

Apache Tika is an useful tool to extract text and metadata from a number of formats.

For example, you have a document pdf, doc,... on the web from which you wish to extract some part. Then you can use tika to extract some part. For this you can use tika:

curl http:urltodoc/.../document.pdf | java -jar tika-app/target/tika-app-0.7.jar --text

produces the text of the document. Other options exist to return an html, an xhtml or only the metadata of the document.

Maven Integration

As for other maven projects, you can specify the dependency in the pom. Note however, that depending on your needs, you might want to specify one of these ( mostly quoted from this page):

tika-core/target/tika-core-0.7.jar Tika core library. Contains the core interfaces and classes of Tika, but none of the parser implementations. Depends only on Java 5.
tika-parsers/target/tika-parsers-0.7.jar Tika parsers. Collection of classes that implement the Tika Parser interface based on various external parser libraries.
tika-app/target/tika-app-0.7.jar Tika application. Combines the above libraries and all the external parser libraries into a single runnable jar with a GUI and a command line interface.
tika-bundle/target/tika-bundle-0.7.jar Tika bundle. An OSGi bundle that includes everything you need to use all Tika functionality in an OSGi environment.

<dependency>
<groupId>org.apache.tika</groupId>
<artifactId>tika-core</artifactId>
<version>0.7</version>
</dependency>

If you want to use Tika to parse documents (instead of simply detecting document types, etc.), you'll want to depend on tika-parsers instead:

<dependency>
<groupId>org.apache.tika</groupId>
<artifactId>tika-parsers</artifactId>
<version>0.7</version>
</dependency>

IBM FileNet P8 Platform

2010-05-05T00:23:00.025+02:00

Disclaimer: This entry is not complete and will be probably be finished later, since some information needs to be checked. The goal is to have a short summary of the documentation I found.

The IBM FileNet P8 Platform is a platform providing enterprise content management. Documentation can be found on the IBM website at this place. A FileNet P8 System Overview can be found there. The source of most of the information for this entry comes from this document.

content management
business objects
Lifecycles
Properties
Events and subscription
classification
entry templates
publishing
content storage
content caching
import and export
search
versioning
process management
extern application integration
form management
record Management (Email management)
system management
application development and deployment
scalability
high availability
disaster recovery
accessability
security
internationalization (i18n)

FileNet uses XML and Java2 Platform, Enterprise Edition (J2EE), as well as mainly the following protocols: Lightweight Direct Access Protocol (LDAP), Hypertext Transport Protocol (HTTP), and SOAP.

Content Management

Business Objects

Lifecycles

Properties

Events and subscription

The platform provides an event framework so as to push to subscribers the given event of the system.

Classification

The FileNet platform provides the infrastructure for different kind of classification of the resources. This classification can either be performed manually but also automatically using specific tools.

Entry Templates

Entry templates provides means of creating objects in a more uniform manner.

Publishing

The platform also provides means of publishing the content stored.

Content Storage

Content Caching

Import and Export

Search

Versioning

The FileNet application provides the tools to perform a versioning of the resource stored in the system.

Process Management

Extern Application Integration

The platform can be integrated in other existing applications such as: Microsoft Office and SAP R/3 and Sharepoint.

Form Management

The documentation of FileNet says that the application provides powerful form creation and management tools.

Record Management (Email management)

System management

Application Development and Deployment

Scalability

One interesting aspect of the FileNet P8 Platform is that it seems to be designed considering scalability issues and techniques. It provides for diverse components horizontal scalability solutions (like computer farms) or vertically (i.e multiple instances of an application can be run in parallel.

Accessability

Accessability is an issuse for enterprise software in order to make sure that every one can use the software. The software is tested according to the Section 508 Compliance based on Electronic and Information Technology Accessibility Standards, published by the U.S. Access Board on December 21, 2000, at 36 CFR Part 1194.. This includes for example key traversal and access.

Architecture

The preceding picture shows the architecture of FileNet, it is taken from the document cited earlier. In addition to this overall picture it should be noted that FileNet provides both a Java and .Net API, although the java API seems to be the one providing the most functionality.

Content Engine

The content engine is the component taking care of the management of the content. It provides all the necessary functionalities, for example secure access, caching, indexing (also full text), search, classification, versioning, life cycles....

The access is either provides through a Java or .Net API or using the Content Engine Web Services. A particular mode when using Java is to use the EJB Means of transport.

Process Engine

The process engine provides a number of components.

Process Analyzer (which is a OLAP component)
Process Simulator to test scenarios
Business Process Framework

Application Engine

Workspace XT - The Graphical Interface

Rendition Engine

Rendition Engine can be used to convert documents to various formats, for example the usual Office formats (Word, Excel, PowerPoint) as well as to PDF or HTML. Multiple Rendition Engines can also be used in order to scale the document conversion process.

Administrative Components

The platform provides a number of adminstrative components: the dashboard, the system usage reporter, the system monitor

UIMA - Unstructured Information Management Architecture

2010-05-04T23:42:00.007+02:00

Disclaimer: This entry is not complete and will be finished later, since some information needs to be checked.

The UIMA (Unstructured Information Management Architecture) is a project which was first created by IBM, but which is now one of the top-level project of the Apache Software Foundation. It provides an architecture to annotate a unstructured information with the help of a set of annotators and analysis engines which can be combined and aggregated.

In the following sections, I will introduce the main elements which allow the understanding of the UIMA infrastructure.

CAS - Common Analysis Structure

The main structure in the UIMA architecture is the CAS (aka. Common Analysis Structure). Note that I had some difficulties finding what it means, but I finally found it in the glossary, which should be read at first because I even in the overview there was no explanation as to what a CAS is.

A CAS is the structure manipulated by the annotators and annotation engines.

Analysis Engines

The UIMA architecture provides the idea of analysis engines which take a CAS View (i.e some annotation structure representing a view of the data) and return a .

Annotators

The glossary of the UIMA documentation defines annotators as:

A software component that implements the UIMA annotator interface. Annotators are implemented to produce and record annotations over regions of an artifact (e.g., text document, audio, and video).

They represent the starting point for the analysis engine.

Indexing

One of the main interest of the UIMA architecture is that it provides a standard interface to define the indexing of the CAS and their views. However, I still need to clear things up here.

PEAR

A PEAR is an archive file packaging the code, descriptor files and other resources required to install and run a UIMA component in another environments. The UIMA SDK provides tools to create such PEAR. Note that the PEAR acronym is not defined in the documentation either.

New Top Level Apache Projects

2010-05-04T22:03:00.005+02:00

In an announcement per mail, the Apache Software Foundation announced a number of new top level projects.

Apache Traffic Server is a richly-featured, fast, scalable, and extensible HTTP/1.1 compliant caching proxy server.

Apache Mahout provides scalable implementations of machine learning algorithms on top of Apache Hadoop and other technologies.

Apache Tika is an embeddable, lightweight toolkit for content detection, and analysis.

Apache Nutch is a highly-modular, Web searching engine based on Lucene Java with added Web-specifics, such as a crawler, a link-graph database, and parsers for HTML and other document formats.

Apache Avro is a fast data serialization system that includes rich and dynamic schemas in all its processing.

Apache HBase is a distributed database modeled after Google's Bigtable.

Apache UIMA (Unstructured Information Management Architecture) is a framework for analyzing unstructured information, such as natural language text.

Apache Cassandra ( an advanced, second-generation “NoSQL” distributed data store that has a shared-nothing architecture)

Apache Subversion a source code management system very often used in enterprise and open source projects.

Apache Click is a modern Java EE Web application framework that provides a natural, rich client style programming model.

Apache Shindig is an OpenSocial container and helps you to start hosting OpenSocial apps quickly by providing the code to render gadgets, proxy requests, and handle REST and RPC requests.

I believe I am becoming somewhat an apache fan boy ;-).

OSGi

2010-05-03T15:44:00.007+02:00

OSGi (used to be "Open Services Gateway initiative") is a standard to define a software platform infrastructure for java. The goal is to have the infrastructure to deploy modularised applications and services with a comnponent model (called Bundles or services). The components can be managed using a service registry. They can be loaded, started and stopped.

The OSGi standard uses metadata found in the Jar file Manifests, in order to load the bundles. In particular, the manifests specifies the classes exported and imported by the bundle. In that way, it is possible to use, or hide conflicting classes in a bundle and not export it. Other bundles may use the classes exported by other bundles.

Bundles

Bundles are jar files with a corresponding entries in the manifest. The following example shows the manifest of a bundle requiring the package org.eclipse.ui.

Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: My Yellow World Example
Bundle-SymbolicName: de.desprofundis.example; singleton:=true
Bundle-Version: 1.0.0
Bundle-Activator: de.desprofundis.example.Activator
Require-Bundle: org.eclipse.ui,
org.eclipse.core.runtime
Bundle-ActivationPolicy: lazy
Bundle-RequiredExecutionEnvironment: JavaSE-1.6

Note the "Require-Bundle", entry which lists the packages which are required by this bundle. The OSGi container is responsible for checking whether the dependencies are satisfied. Another important information is also here the Bundle-Activator, which is the class in charge of the activation of the bundle (as well as its shutting down when needed.

Services

In addition to the dependency management and version hiding, the OSGi framework provides also a registry for services. Moreover, services can be injected in to some other bundle. A tutorial by Lars Vogel presents their use succintly.

Zen Coding

2010-05-03T10:52:00.004+02:00

Zen Coding is an utility to generate simple HTML skeleton structures using a path like expression with some syntactic enhancement. From the demos, it is really quite impressive, because in this way one can generate quite quickly complex HTML structures.

I read the entry on slashdot.org and then followed the link to this blog.

Though I still need to try it. I am amazed. I have to make it work in eclipse and emacs (aswell as perhaps vi).

Javascript Performance Talk

2010-04-29T12:23:00.008+02:00

I watched the javascript performance talk from Nicholas C. Zakas at Google Tech Talks: Nicholas C. Zakas: Speed Up Your JavaScript.

Scope Management
Loop optimization
About HTMLCollection Live objects
Document Fragments - postponing reflow

Scope Management

The tip given to improve efficiency is to use local variables, because variables which are in the local scope are accessed first. Every time a global or a variable from a prototype or a dot object variable is accessed twice. Use a local variable.

Another issue related to the scope aspect is that using functions and closures comes with a certain cost.

Loops Optimization

Loops can be optimized in different ways, when avoiding unnecessary work.

About HTMLCollection Live objects

The presentation explains that the collection returned by methods such as: .getElementsByTagName, ... return HTMLCollection objects which remain 'live', that is they get updated. A typical example is the following loop:

var divs = document.getElementsByTagName('div');

for (var i = 0; i< divs.length; i++){
var div = document.createElement('div');
document.body.append(div);
}

The collection in divs is an HTMLCollection. The body of the loops goes over the loops and adds a div for every object in the collection. But since new objects are added to the loop every time one goes through the loops, the loops never ends !!!!!

DocumentFragment - postponing reflow

Reflow occurs when the the size of the elements on the page are recalculated. To improve performance it is useful to minimize the number of reflows.

In general, Nicholas C. Zakas explained that reflow happens at five particular moments in browsers:

Page load
browser window resize
adding and removing elements
setting style attribute of elements
(sometimes) accessing the style elements of the nodes

To prevent useless reflows, one can use a document fragment in order to create a quite complete element as a document fragment and then add it to the DOM. In this way, reflow is only performed when the element is added to the page.

To minimize the access to the style attributes of elements, a better way to perform that is to change the class of the element, i.e: use .className instead of .style.

Behavior Driven Development (aka. BDD) using EasyB

2010-04-28T14:05:00.008+02:00

One more term for "test driven development", behaviour driven development. The idea behind the change in term is to highlight, that the principle underlying behind this style of development is more a design methodology as a test methodology.

To illustrate the purpose, and methodology, I will present it here using easyb.

The main idea is to write the specification as text, and then to replace the text using groovy code. Easyb provides two types of tests: specifications and stories.

I first describe the specification by giving an example.

before "initialize the queue for each spec", {
queue = new Queue()
}

it "should dequeue gives item just enqueued", {
queue.enqueue(2)
queue.dequeue().shouldBe(2)
}
it "should throw an exception when null is enqueued", {
ensureThrows(RuntimeException){
queue.enqueue(null)
}
}

easyb uses a number of keywords and methods. First of all, the keyword before for the code to be used when setting the test environment at the beginning. In this case a queue is created. The next important keyword is "it" at the beginning of certain lines. It indicates that this is a specification. It is followed by a text describing the specification. Finally, after the description some groovy code is included between "{" and "}".

Different methods belong to the easyb specification language: "shouldBe" and "ensureThrows". The first one checks that the result of the emthod to which it is applied returns a given value, whereas the second one verifyies that an exception as been thrown.

Maven Configuration

As usual, I find very useful to have a template of what I need in a maven pom to use somekind of framework. I haven't tested that yet. I still find that useful:

<project>
...
<repositories>
   <repository>
     <id>easyb</id>
     <url>http://www.easyb.org/maven2/</url>
    </repository>
   </repositories>
   <pluginRepositories>
    <pluginRepository>
     <id>easyb</id>
     <url>http://www.easyb.org/maven2/</url>
    </pluginRepository>
   </pluginRepositories>
   ...
</project>

Easyb clone for javascript

I also found the following code to perform bdd in javascript: JavaScript BDD framework in less than 200 lines.

A site for Javascript library

2010-04-27T02:21:00.001+02:00

As I was looking for a Java based implementation of javascript. I fell upon the following site: http://javascriptlibraries.com/ which will probably be useful.

Learning Python 3.0

2010-04-27T02:12:00.009+02:00

I am learning python 3.0. There are a few reasons for this. For instance, there is a suggestion from the 'Pragmatic Programmer' book I bought lately. This other thing is that it would make it easier to cooperate with my brother and to perform more useful stuff for and with him. I am also using Mark Lutz: Learning Python (Fourth Edition from Oreilly).

So I installed pyhton 3.0 on my machine.

$> ./configure
$> su
$> make altinstall

And here it is:

$ /usr/local/bin/python3.0
Python 3.0 (r30:67503, Apr 27 2010, 01:32:05)
[GCC 4.4.3 20100127 (Red Hat 4.4.3-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

I will probably need to make a few tests that everything works.

Mockito - basics

2010-04-23T18:33:00.013+02:00

This entry gives simple methods on how to use mockito.

Maven configuration

To add mockito-core to your configuration, update your dependencies with:

<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>1.8.1</version>

In order to add the complete mockito framework, i.e. mockito-all, update your dependencies with

<groupId>org.mockito</groupId>
<artifactId>mockito-all</artifactId>
<version>1.8.1</version>

Of course if the mock code is only found in unit tests, then you might want to add:

<scope>test<scope>

to your pom.xml

Use of Mocks to verify interaction (Spying)

The following example is adapted from the mockito documentation

// the staic import allows the direct use of the help methods: mock and verify
import static org.mockito.Mockito.*;

// create a mock of a map
List mockedMap = mock(Map.class);

//using mock object
mockedMap.put("key", "value");
mockedMap.clear();
//verification
verify(mockedMap).put("key","value");
verify(mockedMap).clear();

Stubbing - Or Have your objects mock others

While the previous section was used to verify that some operation did occur on a specific object. In some cases, you may not wish to initialize completely a complex object. In such a case, you can use mockito to perform stubbing, i.e. mockito provides an interface, so that the object returns a specific value, when a call to a method is performed.

For instance, it is possible to use the mocking framework to return a given result for certain parameters:

when(mockedMap.get("key")).thenReturn("first");
when(mockedList.get(5)).thenThrow(new RuntimeException());

Content delivery network

2010-04-23T16:26:00.003+02:00

Content delivery network are a cool thing though I am not sure how secure is such an approach. I will have to take a closer look.

In particular in the case of using dojo, a few issues have to be taken into account.

Interesting seems that google provides an api for asynchonuous loading.

Browser based javascript library loading

Wouldn't it be interesting to have browser taking care of the javascript frameworks library loading such as dojo, ext, ... in the version corresponding to some specification in the HTML file.

Dojo Toolkit - Basics

2010-04-23T16:20:00.015+02:00

This is a high level overview of the dojo toolkit.

Function called on load
package framework
a DOM element retrieval mechanism
a number of Widgets
Helper Methods
Dojo Array Methods
dojo.connect - Event mechanism
Parsing, formatting and validation of numbers and dates
Ajax request tools
An history and bookmarking mechanism
Event System tools
Animation tools
I18n tools (Internationalization)

Loading the dojo code

The code of dojo can be loaded from http://ajax.googleapis.com/ajax/libs/dojo/1.4/dojo/dojo.xd.js. I would like to try loading it from the web server.

Function called on load

As for other web frameworks, you can have different function called on load:

dojo.addOnLoad(funtion( // code to perform on load ));

package framework

The dojo toolkit provides a package mechanism, the code is used in the following way:

dojo.require('dojo.fx');

loads the dojo.fx package.

a DOM element retrieval mechanism

Dojo provides a number of methods to retrieve elements of the DOM document. For instance, dojo.byId('myId'); retrieves the element with the id 'myId' just as document.getElementById would.

Just as other frameworks dojo provides also a query mechanism.

From the dojo documentation:

// all <h3> elements
dojo.query('h3')
// all <h3> elements which are first-child of their parent node
dojo.query('h3:first-child')
// a node with id="main"
dojo.query('#main')
// all <h3> elements within a node with id="main"
dojo.query('#main h3')
// a <div> with an id="main"
dojo.query('div#main')
// all <h3> elements within a div with id="main"
dojo.query('div#main h3')
// all <h3> elements that are immediate children of a <div>, within node with id="main"
dojo.query('#main div > h3')
// all nodes with class="foo"
dojo.query('.foo')
// all nodes with classes "foo" and "bar"
dojo.query('.foo.bar')
// all <h3> elements that are immediate children of a node with id="main"
dojo.query('#main > h3')

A number of Widgets

The dojo toolkit provides a number of widgets. These can be retrieved by the dijit.byId() method.

Dojo Array Methods

Dojo provides some other useful methods for example: dojo.forEach(). A similar method can be used on the resuklt of a dojo.query().

Dojo also provides filter and map functions. filters an array and returns all the elements verifying a given property. The map function applies some function on all the elements of an array and returns a new array of new values.

The functions dojo.some() and dojo.every() checking that some property is true for some, respectively all the elements of the array

dojo.connect - Event mechanism

The dojo toolkit provides the dojo.connect methods which allows to connect some event to a given event.

Parsing, formatting and validation of numbers and dates

Ajax request tools

An history and bookmarking mechanism

Event System tools

Animation tools

I18n tools (Internationalization)

Java Web Framework Comparison

2010-04-23T15:48:00.004+02:00

Here is an useful link for comparing the different existing Java web frameworks.

In particular, "java Web Frameworks sweet spots" is quite interesting.

I learnt about a framework I yet had never heard of: RIFE. The developer, who was asked in the article, seems to be a little too subjective for my taste.

Flex - generating Flex on Java Project

2010-04-22T02:08:00.014+02:00

I collected the following from The Flex On Java Book.

$workspace > mvn archetype:create -DarchetypeGroupId=org.foj -DarchetypeArtifactId=flex-mojos-archetype -DarchetypeVersion=1.0-SNAPSHOT -DgroupId=org.foj -DartifactId=flex-bugs-ria -DremoteRepositories=http://flexonjava.googlecode.com/svn/repository

However, I still need to solve some dependency problems. In particular I needed to install the following packages:

com.adobe.flex.compiler:asdoc:zip:template:3.2.0.3958
org.graniteds:granite-generator:jar:1.1.0
com.adobe.flex:compiler:pom:4.0.0.7219

But this is solved by using the correct repository by adding
<repositories>
   ...
    <repository>
       <id>flexcompiler-repo</id>
       <url>http://repository.sonatype.org/content/groups/flexgroup/</url>
    </repository>
</repositories>

However, after running:

$flex-bugs-ria >mvn package

it runs quite a while with an error. It seems it just could not start the flash player. So it may be all good ;-).

It returns successful and the generated swf can be displayed in the browser

$flex-bugs-ria >mvn package-Dmaven.test.skip=true

Next step: do a more complex flex example.

Mock Frameworks

2010-04-22T01:05:00.011+02:00

In this entry, I present a summary of the features of mock frameworks. In particular, I looked at two different mock frameworks: easyMock (MIT Licence), Mockito (Apache Licence) and JMock (probably equivalent to BSD, MIT or Apache but I am not completely sure). The Mockito framework seems to be trying to extend even more the features of the easy mock.

Usual Use Cases of Mock Objects

I adapted the following list from a wikipedia entry. It shows the cases where it a good practice to use mocks.

results of method do not follow a very deterministic pattern
The mock can simulate a complex object or an object difficult to obtain, e.g a given state in a GUI
A state of a system which is expensive to create, resource, processing, power...
The object has not yet been provided, perhaps by an other team

Here are some useful posts on mocks:

Mocks, Fakes, Stubs and Dummies , Gerard Meszaros explaining the different type of test doubles.
Let's Spy
Mocks and Stubs aren't Spies

I notice this post is not at all too clean. It needs to explain the purpose of spying and the difference there is with mock objects which are only dummy object or fake object.

Ext JS Feature Overview

2010-04-22T00:33:00.008+02:00

After implementing a whole application with Ext JS, and after presenting also in this blog basic overview of the prototype and jquery javascript frameworks and given a small idea of the functionalities of qooxdoo (and a little overview of QWT), I want to give a more or less thorough view of all the features of this quality framework. In a later entry, I will give a thorough presentation of the relations between GWT and Ext JS.

It is important to notice, that unlike other frameworks the extJS framework does not have a licence mechanism which is very suitable for enterprise application which need to be kept closed source, unless you are ready to pay licence fees to the company owning the code of extJS. However, the core of ext JS is proposed under an LGPL licence, so it can still be used in closed source development.

I first list the main features of extJS, then I go in a little more details for each of these points:

Namespace functionalities
DOM elements manipulation Utilities
Data Manipulation Utilities
Data Store functionalities
Ajax request functionalities
an extended set of application widgets: trees, tables form, charts
a complete RIA framework, with menus, drag and drop,....