XSLT

XSLT an XML-based, declarative and functional programming language.

declarative programming

A style of programming that concentrates on what to do, rather than how to do it, as opposite to imperative programming.

A common example of declarative programming would be an HTML document (which describes the structure of the page, but not how to actually construct the view.
At least, in principle.)

imperative programming

In imperative programming is traditional way of programming, a sequence of instructions to be executed.
For ex
do this task
do that task
do another task

imperative programming is about telling a computer how to do something

functional programming

In functional programming rather than presenting a program as a series of steps, it's represented with interdependent math-style functions,
where you set one value, a variable, and all the contingent values snap into place, like a spreadsheet.

Programs are viewed as descriptions of problems rather than instructions.

What type of files is .rar extension?

rar is another archive mechanism to save the space.
Download the archive binary from the following location.

jasper reports (Free Java open source reports framework )

Recently I worked with the following open source reports framework.
It was very promising to me.
May be I will give sample prototype code in this site later.
Basically it is free & extensible & simple reports engine.

Java 2 1.4.2 API specification

Just core Java platform API's only.

new book in my book collection

Book info:
Title: Service oriented architecture
a field guide to integrating XML and web services.

Author:
By Thomas Erl

I started reading the above book. (Just few pages only.)
I liked it.
Read the reviews the above link. See other users reviews too.

LCD monitor Dead Pixels Test

good one.

Java sorting strings

// Sorts the input arguments

public static void main(String[] args)
{
//just sort the input command line args
Arrays.sort(args); // sorting works for many primitive data types
//sorting objects will be another section.
//Print the sorted array
for (int i=0; i .lt. args.length;i++)
{
System.out.println(args[i]);
}
}

Java Swing To Set custom Look and Feel to UI

if ( setcmd txt is "Windows")
{
lfName = "com.sun.java.swing.plaf.windows.WindowsLookAndFeel";
}

try
{
UIManager.setLookAndFeel(lfName);
}
catch (UnsupportedLookAndFeelException ex1)
{
System.err.println("Unsupported LookAndFeel: " + lnfName);
}

Eclipse SWT vs. Java Swing

Good article.

copy xml document via xslt.

Few months back, one guy stopped by office & asked me I want .xsl file to copy the incoming xml file. At first I am bit shocked why you want to do that, later he explained the scenario. Immediately I got confused how to ? but did it in 10 minutes. But a crazy scenario. here is code for that part.

.lt. xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" .gt.
-- match the root node and copy it --
.lt. xsl:template match="/" .gt.
.lt. xsl:copy-of select="."/ .gt.
.lt./xsl:template .gt.

.lt./xsl:stylesheet.gt.

.lt. less than symbol .gt. greater than symbol

Eclipse 3.0 onwards. Using ImageRegistry & plugin your own images

The ImageRegistry is intended to be used for Images
that appear frequently in your plugnin UI.
To use ImageRegistry make sure your Plugin class a subclass of org.eclipse.ui.plugin.AbstractUIPlugin.

This class creates an ImageRegistry automatically (one per plug-in instance) and
override/implement the following methods.


public Image getImage(String id)
{
ImageRegistry ir= getImageRegistry();
return (Image)ir.get(id);
}

public ImageDescriptor getImageDescriptor(String id)
{

ImageRegistry ir= getImageRegistry();
return (ImageDescriptor)ir.getDescriptor(id);
}


protected void initializeImageRegistry(ImageRegistry image_registry)
{

ImageDescriptor desc = ImageDescriptor.createFromURL(generateURL("myOwnImage1.gif"));
image_registry.put("myOwnImage1",desc);
}

private URL generateURL(String file_name)
{
Bundle bundle = Platform.getBundle(PLUGIN_ID);
String iconPath = "icons/";
String completePath= iconPath+file_name;
IPath path = new Path(completePath);
URL url = Platform.find(bundle,path);
return url;
}

Java Sample code to write exception stack trace in to a file.

My previous code is too big. So I will add small code today.
Normally in the try catch block, if we have exception object, we will print exception object with printStatckTace, getErrorMessage etc. But I faced a situation in which, I need to log all the exception trace back stack in to a text file. Later admin want to view this log file for all tracebacks.
Just think how to write exception trace in to a txt file.
Here is the code block for the above problem.

StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
e.printStackTrace(pw);
StringBuffer error = sw.getBuffer();
String exceptionString = error. toString()
Note: StringWriter, PrintWriter classes comes from io package.

Validating XML files under a web application. ( aka a file system path.)

Following code parses xml files under a directory. (It was recursive one.)
We have a web application which is very much similar to struts framework.
So we have tons of xml preference files.
Before launching tomcat, I will invoke the following code to make sure that
all xml files were valid one.

public void parseDirectory(String fullpath)
{
if ( fullpath == null) return;

Path path = new Path(fullpath);
File file = path.toFile();
File[] files = file.listFiles();
if (files==null) return;
int size = files.length;

for (int i=0; i .lt. size; i=i+1)
{
if (files[i].isDirectory())
{
File[] dirFiles = files[i].listFiles();
String dirName =files[i].getName();

System.out.println("\n processing directory"+dirName);
for (int j=0; j .lt. dirFiles.length; j=j+1)
{
File subDirFile = dirFiles[j];
String subDirFileName = subDirFile.getName();
if ( subDirFileName.endsWith(".xml"))
{
parseXmlile(files[i].getName();
}
else
{
if ( subDirFile.isDirectory() ) parseDirectory(subDirFileName);
}
}
}
else
{
String fileName = files[i].getName();
if ( fileName.endsWith(".xml"))
{
parseXmlile(files[i].getName();
}
else
{
// it is not a xml file & directory.. so skip it.
}
}
}
}




public void parseXmlile(String fileName)
{

try
{
System.err.println("Parsing " + fileName + "...");
// Make the document a URL so relative DTD works.
String uri = "file:" + new File(fileName).getAbsolutePath();
XmlDocument doc = XmlDocument.createXmlDocument(uri);
System.out.println("Parsed OK...");
}
catch (SAXParseException ex)
{
System.err.println("================================");
System.err.println("| *Parse Error* |");
System.err.println("================================");
System.err.println("+ Line " + ex.getLineNumber ()
+ ", uri " + ex.getSystemId ());
System.err.println(ex.getClass());
System.err.println(ex.getMessage());
System.err.println("================================");
}
catch(SAXException ex)
{
System.err.println("================================");
System.err.println("| *SAX XML Error* |");
System.err.println("================================");
System.err.println(ex.toString());
}
catch (IOException ex)
{
System.err.println("================================");
System.err.println("| *Input/Output Error* |");
System.err.println("================================");
System.err.println(ex.toString());
}
catch (Exception ex)
{
System.err.println("================================");
System.err.println("| Unknown error |");
System.err.println("================================");
System.err.println(ex.toString());
}
}

Eclipse 3.0 onwards. A Light Weight Decorator sample.

Eclips 3.0 onwards only. for plugin developers.

Sample code to implement powerful Light Weight Decorator to
paint tree and XXX nodes.
I used it to paint tree nodes in my project to show different images on top
of standard tree folder,+,- signs.

1) plugin.xml add the following node.
point="org.eclipse.ui.decorators">
decorator
adaptable="true"
label="%plugin.my_label"
state="false"
lightweight="true"
location="BOTTOM_RIGHT"
class="com.xxx.TreeLabelProvider"
id="com.xxx.views"
enablement
objectClass
name="com.xxx.TreeObject"
objectClass
enablement
decorator
extension
stpid tool is not allowing me enter comple xml syntax.
2) open tree object class & add/ implement the following.

TreeLabelProvider extends LabelProvider
implements ILightweightLabelDecorer

implement
public Image getImage(Object element)
public String getText(Object element)
and
public void decorate(Object element, IDecoration decoration)
{
if (element instanceof TreeObject)
decoration.addOverlay(error,IDecoration.BOTTOM_RIGHT);
}
catch relation between TreeLabelProvider & TreeObject.
U are done. enjoy.

creating read-only views of collections inside a application

// create a list and add some items to it

List stringlist = new ArrayList();
stringlist.add("alpha");
stringlist.add("beta");
stringlist.add("gamma");

// create an unmodifiable view of the list

List rolist = Collections.unmodifiableList(stringlist);

// add to the original list (works OK)

stringlist.add("delta");

// add through the read-only view (gives an exception)

rolist.add("delta");

dumping system properties

Just to dump java System class properties.

try
{

////dumping system properties.

// Note1) If property is duplicated it will use the later value for key value

Properties p = System.getProperties();
Enumeration e= p.propertyNames();
for ( ; e.hasMoreElements();) {
String o =(String) e.nextElement();
System.out.println( "\n Key="+ o);
System.out.println( " Value="+ p.getProperty(o) );

}

}
catch (Exception e)
{
System.err.println("Directory " + e.getMessage() + " is invalid.");
e.printStackTrace();
}

parsing a Date string

U got date input as string. (In some MM/DD/YYYY format)
Now I want the equivalent Java date object.
(For further validity & further processing.)
Use the following segment.


public static void main(String args[])
{
String dt = "10-10-1990"; // some test data

try{

SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy");
// input date format
format.setLenient(false);
Date date = format.parse( dt );
System.out.println("The parsed date: " + date);
} catch (ParseException e) {
System.out.println(e.getMessage());
}