Andreas Höhmann's Weblog

Levelhead game

Andreas Höhmann — Wed, 11 Nov 2009 08:00:56 +0000

Disable backspace key in a Richfaces application

Andreas Höhmann — Fri, 06 Nov 2009 13:50:12 +0000

If you want disable the Backspace key in your JSF Richfaces application put this in your view:

This will register a jQuery Hotkey handler for the document. The handler is not reqistered for input elements because in input fields you need the backspace . Tested for FF3 and IE6.

Then I found out that the following snippet doesn’t work:

The Browser open the alert box and go to the previous page (in background?!). But there is a fix for that:

The event variable is available in the handler function (see org.richfaces.renderkit.html.HotKeyRenderer method doEncodeEnd).

Better IE scroll bar bugfix

Andreas Höhmann — Tue, 03 Nov 2009 14:14:18 +0000

Today I want to write about a better fix for the “ie scroll bar bug”.

First a short description of the problem … a picture says more than 1000 words:

The horizontal scroll bar become visible as a result of the shown vertical scroll bar.

But I’m expecting this:

I found some articles about solutions to void the unnecessary x scroll bar in internet explorer:

use IE quirks mode – selfhtml
use overflow-x: hidden – selfhtml, blog
conditional comments with overflow-x: hidden: selfhtml

The IE quirks mode workaround is not my prefered solution, I want use the xhtml 11 doctype

“http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>

To hide the horizontal scoll bar is usefull if you doesn’t have content that can overflow the views width, i.e. if the view-content have a”width of 100%. But if you have view-content with a dynamic width (!= 100%) then you need horizontal scroll bars.

Here is my solution:




  


  
    
      
        
          width: 400px; height: 2000px;
        
        Foobar

My solution based on conditional css styles verticalScrollerContainerFix and verticalScrollerContainer. The structure is always the same:

    
      
      
        
        YOUR CONTENT HERE

Try it

Toggle jrebel with a cygwin bash function and maven

Andreas Höhmann — Mon, 02 Nov 2009 13:57:16 +0000

I’m using java rebel for web development with maven.

Sometimes I would run jetty with jrebel sometimes without.

For that I’m using two simple bash functions:

# ~/.bashrc

#
# Maven options
#
export INTERNAL_MAVEN_OPTS="-Xmx512m -XX:PermSize=128m -XX:MaxPermSize=128m"

#
# Java Rebel
#
export JAVA_REBEL="-Drebel.spring_plugin=true -Drebel.log=false -noverify -javaagent:D:\tools\javarebel\jrebel.jar -Drebel.packages=de.ahoehma"

function jrebel_on() {
 export MAVEN_OPTS="$INTERNAL_MAVEN_OPTS $JAVA_REBEL"
}

function jrebel_off() {
 export MAVEN_OPTS="$INTERNAL_MAVEN_OPTS"
}

Now its very simple to enable

$ jrebel_on

or disable jrebel

$ jrebel_off

Private Digitalkopie bleibt erlaubt

Andreas Höhmann — Thu, 29 Oct 2009 17:45:55 +0000

Quelle: handelsblatt

Wie im Urheberrechtsgesetz §53 nachzulesen:

(1) Zulässig sind einzelne Vervielfältigungen eines Werkes durch eine natürliche Person zum privaten Gebrauch auf beliebigen Trägern, sofern sie weder unmittelbar noch mittelbar Erwerbszwecken dienen, soweit nicht zur Vervielfältigung eine offensichtlich rechtswidrig hergestellte Vorlage verwendet wird. Der zur Vervielfältigung Befugte darf die Vervielfältigungsstücke auch durch einen anderen herstellen lassen, sofern dies unentgeltlich geschieht oder es sich um Vervielfältigungen auf Papier oder einem ähnlichen Träger mittels beliebiger photomechanischer Verfahren oder anderer Verfahren mit ähnlicher Wirkung handelt.

Die Klage der Musikindustrie wurde aus formalen Gründen abgelehnt.

Siehe auch hier: Gesetz über Urheberrecht und verwandte Schutzrechte

Quality Center Mylyn Integration

Andreas Höhmann — Wed, 28 Oct 2009 07:54:59 +0000

There is a interesting project at sourceforge called qcMylyn. The projects aims to provide a Mylyn connector for Quality Center. Support Eclipse 3.4.2, 3.5, Mylyn 3.0.5+.

I tried the released version 0.2.4 but it didn’t work because at work we are using an older version of QualityCenter (9.1). But this was no big problem I have the sourcecode (OS rocks) and I’m a programmer

I found out that a other project called QcTools4J contains the java code for manipulation a QC system. They using a com4j bridge to bind QC’s otaclient.dll.

If you have trouble with a older/newer version of QC you have to update the qctools4j.

You find a short tutorial how to update qctools4j here. (read this first) … then you will come to the point where you want create a new otaclient.jar from you local otaclient.dll. Here is my simple solution for that.

I create my own otaclient maven project with the following pom:


      4.0.0
      otaclient
      otaclient
      9.1.0.4372
      
        
          org.jvnet.com4j
          com4j
          20080107
        
      
      
        
          
            maven-compiler-plugin
            
              1.5
              1.5
            
          
          
            org.jvnet.com4j
            maven-com4j-plugin
            
              
                gen-java-bridge
                
                  gen
                
                
                  src/qc/OTAClient.dll
                  com.mercury.qualitycenter.otaclient

I using the maven-com4j-plugin to generate the java layer for otaclient.

All you have to do is to extract your “qc client package” (could be download from every qc server page) into src/qc and start mvn clean package.

Then target will contain a otaclient-9.1.0.4372.jar. Copy this jar into qctools4j/lib/com.mercury.qualitycenter.otaclient-9.2.jar and rebuild qctools4j. That’s all

Then copy the qctools4j.jar into org.tszadel.qctools and rebuild the whole eclipse feature.

Try it

Google Konfuzius Image

Andreas Höhmann — Mon, 28 Sep 2009 10:31:28 +0000

Today the google image contains a quotation from the first didactic play of Lùnyǔ:

有朋自遠方來，不亦樂乎?

In pinyin this meens

1	2	3	4	5	6,	7
yǒu	péng	zì	yuǎn	fāng	lái,	bùyìyuèhū
有	朋	自	远	方	来,	不亦乐乎

1	exists, have, there is
2	friend
3	from
4	far, away
5	square
6	come
7	???

If a friend visits you from far away, it is always a joy. Isn’t it?

or in german

Wenn ein Freund von weit her kommt, ist das nicht auch eine Freude?

My favourite java ide is eclipse

Andreas Höhmann — Mon, 21 Sep 2009 18:27:59 +0000

Customized Richfaces Tree

Andreas Höhmann — Thu, 10 Sep 2009 11:42:02 +0000

Yesterday I had to customize the Richfaces tree component, because my client wants a special layout. My solution is a little bit strange. I share it here for someone which is in the same situation Here is the story …

Per default the rich:tree looks like a standard tree browser (i.e. explorer, eclipse, whatever):

But I want this look:

You see that the expand/collapse icon () is on the same level with the node-icon (). That’s very hard to fix this with CSS (it’s possible but i prefer my strange solution ). The Richfaces documentation describes which parts of a tree could be customize.

We have:

rich-tree-node-handle and rich-tree-node-handleicon – a td which contains a link and a image to expand/collapse the node (only possible for a node not a leaf)
rich-tree-node-icon – is a td which contains the image for a node (a node with children)
rich-tree-node-icon-leaf – is a td which contains the image for a leaf (a node without children)

I decide to move the expand/collapse icon from the handle-td to the icon-td and “simulate” the user-click with Javascript:

Listing 1 tree.xhtml:

Listing 2 tree.js:

function myToggleTreeNode(element) {
  var elem = jQuery(element);
  // img -> span -> td
  var parent = elem.parent().parent();
  var elementId = parent.attr("id");
  // i.e. j_id31:tree:j__id39:18::j_id40:icon -> the td arround the icon-image
  var index = elementId.lastIndexOf(":icon");
  var treeNodeId = elementId.substring(0, index);
  // i.e. j_id31:tree:j__id39:18::j_id40:handle -> the td arround the original expand/collapse-image
  var handleId = treeNodeId+':handle';
  // pure jQuery not working here
  var expandElement = jQuery($(handleId));
  expandElement.trigger("click");
}

Listing 3 tree.css:

.rich-tree-node-handleicon {
  display: none;
}

Nice example for a checked unchecked exception

Andreas Höhmann — Wed, 09 Sep 2009 20:28:04 +0000

Today I found a nice example for a “checked null pointer exception” in Ed burns blog.

@Override
public void encodeAll(FacesContext context) throws IOException {
   ResponseWriter writer = context.getResponseWriter();
   String viewName, libraryName, resourceName;
   try {
     viewName = this.getAttributes().get("viewName").toString();
     libraryName = this.getAttributes().get("libraryName").toString();
     resourceName = this.getAttributes().get("resourceName").toString();
    } catch (NullPointerException e) {
     throw new FacesException("Must supply viewName, libraryName and resourceName attributes");
   }
   ...
}

I have always tried to avoid NPE’s with code like this:

if (foobar == null) {
  throw new IllegalArgumentException("foobar must not be null").
}

But from now I will try to use the “checked” version of a npe check above more often.

Read more about checked / unchecked exceptions here:

[a] http://www.javapractices.com/topic/TopicAction.do?Id=129
[b] http://en.wikipedia.org/wiki/Exception_handling#Checked_exceptions
[c] http://de.wikipedia.org/wiki/Ausnahmebehandlung#Checked_Exceptions
[d] http://java.sun.com/docs/books/jls/second_edition/html/exceptions.doc.html
[e] http://www.mindview.net/Etc/Discussions/CheckedExceptions