It is good to use alert(message) in Javascript to debug a program. Hovewer later I deleted created earlier javascript, which took hidden parameters from the form and submited it in a custom way, so that the number of parameters for the next jsp page became less.

html/css part developing is not that fast though.

Work with transactions was using this book

I tried to play with the UML plugin for eclipse from http://www.soyatec.com/euml2/, quite slowly, hovewer at the end the hand made scratch was put into the project, as this requirement came to my mind too late, I hope this plugin still will help.

But the project is working with the main task: writing opinions to the database, and reading the opinions of others, so it is like a forum. An email is not published to everybody, as it is not necessary. The authentication part is hidden under the comments for faster debugging.

 
public static List Select_QualitiesForCategory(int categFine) {
//qualities of one category only
List liszt=new ArrayList();
Transaction tran = null;
Session session = null;
try{
SessionFactory sessionFactory = new Configuration().configure(new File("D:/eclipse/EWEc/ForumW/src/hibernate.cfg.xml")).buildSessionFactory();
session =sessionFactory.openSession();
tran = session.beginTransaction();

return liszt;
}

SessionFactory sessionFactory = new Configuration().configure(new File("D:/eclipse/.../hibernate.cfg.xml")).buildSessionFactory();
session =sessionFactory.openSession();
Criteria crit = session.createCriteria(qlist.class);
List query = crit.list();
for(Iterator it=query.iterator();it.hasNext();){
qlis= (qlist) it.next();
if ((int)qlis.getquality_id()==categFine)
listt.add(qlis);
System.out.println(qlis.getqcateg_id()+"_"+categFine);
}
session.close();

I tried using transactions and restrictions as well. Did not help. For example:
public static List Select_QualitiesForCategory(int categFine) { //qlist, qualities of one category only
Session session = null;
List listt = new ArrayList();
try{

SessionFactory sessionFactory = new Configuration().configure(new File("D:/eclipse/EWEc/ForumW/src/hibernate.cfg.xml")).buildSessionFactory();
session =sessionFactory.openSession();
Criteria crit = session.createCriteria(qlist.class);
List query = crit.list();
crit.add(Restrictions.like("qcateg_id", categFine));
crit.setMaxResults(100);
for(Iterator it=query.iterator();it.hasNext();){
qlist qlis= (qlist) it.next();
if ((int)qlis.getquality_id()==categFine)
listt.add(qlis);
System.out.println(qlis.getqcateg_id()+"_"+categFine);
}
session.close();
}catch(Exception e){
System.out.println(e.getMessage());
}finally{
}
System.out.println(listt.size());
return listt;
}

And the output contains lots of duplicates. However in the db all names are unique.

1) jre6 and then Eclipse IDE for Java Developers

Version: Helios Service Release 1

Build id: 20100917-0705

2) JBossTools 3.2.0 (eclipse – help/install new software)

http://download.jboss.org/jbosstools/updates/stable/helios/

3) mysql-5.5.13-win32.msi

 http://www.mysql.com/downloads/mirror.php?id=402882#mirrors

started MySQL 5.5 Command Line Client, created all tables with data filled in

4) In eclipse created new dynamic we project called Forum, during which I pointed new runtime environment – JBoss 6.0 Runtime, and new local server. Can not finish this operation because of the error “ The home directory does not exist or is missing the run.jar.”.  Took jboss-as-distribution-6.0.0.Final, unzipped and pointed a folder in same window with project creating, and also in CLASSPATH. Server: default, behavior: local. Dynamic web module version: 3. Default configuration for JBoss 6.0 Runtime. Ticked Generate web deployment descriptor.

5) Extremely fast created all beans, servlets, classes and added necessary files, then created xml configuration. Problem with creating reverse engineerng file – “Error while refreshing database tree”. Which means that connector hasn’t been pointed yet. mysql-connector-java-5.1.16-bin. Added all jars into project build path from my ready folder with a set of libs. Then to be sure everything is fine: menu-window-show view- hibernate – hibernate configuration file – gives me an error “could not parse mapping document” of one of the beans. On one of the forums it was written “Your sample.hbm.xml doesn’t define an ID. Make sure you properly map the id of the object to the primary key of your entity. “. And yes, mapping in the file hibernate configuration xml is not required. Removed it, not everything expands well.

6) Window – show view servers. Then added the project into the list for the server. Full publish. Start server. index.html was showed correctly. But the reason of bad usage of direct path in new Configuration().configure(new File(“C:/…/src/hibernate.cfg.xml”) did not allow to go further. The path changed since then. Changed. Full publish. The selection from the db was not done. I created mapping again in conf file, this time no error about duplicate mapping. Then I created reverse engineering file. Full Publish. It works!!! Finally.

1) Eclipse Helios: Eclipse IDE for Java Developers, version: Helios Service Release 1, build id: 20100917-0705

2) mysql-5.5.13-win32.msi from http://www.mysql.com/downloads/.
(complete installation, custom configuration, in environment variables included bin directory in CLASSPATH)

3) Antivirus Anvir was working all time, did not create any problems. From last time the location (or at least the version) of jre was changed, so in project-properties-java build path –JRE system library I chose a new location (already built in eclipse)

4) JBOSS using Eclipse – help/install new software (JBoss Tools Requirements – Composite Helios Mirror – http://download.jboss.org/jbosstools/updates/helios/ , checked the box )

5) Using MYSQL 5.5 command line client created all necessary tables and filled in with data (there were problems only with quotes interpretation (all symbols ‘ to `), simple replacement helped to solve them. An interesting moment is that both types of quote pairs is required, for example only this way it works:

INSERT INTO qlist (`quality_id`, `qcateg_id`, `quality`) VALUES

(1,4,’Active’), …

)

6) Downloaded mysql-connector-java-5.1.16.zip from http://www.mysql.com/downloads/mirror.php?id=402367. Few days were spent to understand that connector.jar was already old. A new one was downloaded: mysql-connector-java-5.1.5-bin.jar

7) Also an archive with JBoss 6.0 final was unzipped, and the lib folder was pointed in CLASSPATH (connector.jar was copied to the folder jboss-final/server/default/lib as well) according to this tutorial http://dev.mysql.com/doc/refman/5.5/en/connector-mxj-install-jboss.html

8) Added javax.servlet.jar (downloaded from http://www.java2s.com/Code/Jar/STUVWXYZ/Downloadjavaxservletjar.htm ) to the build path in Eclipse-project-properties. This file javax-servlet.jar was put into CLASSPATH as well.

9) JAVA_HOME was set correctly to jdk folder at the very beginning. I have jdk1.6.0_25, by the way.

10) Select from the menu New | Other | Hibernate | Hibernate Configuration File.
Configured it exactly as described in http://www.mastertheboss.com/hibernate/284-hibernate-jboss.html?start=1

Problem the same as 6.01.11: Database in view “Hibernate Configurations” could not be expanded.

Instead “Reading schema error: Getting database metadata” appeared.
I indicated localhost:8080/dbname, instead of localhost/dbname.

11) Now the project class: writetoDB has two problems with import:

import com.sun.tools.ws.wsdl.document.Output;
import javax.servlet.jsp.JspWriter;

Added j2ee.jar (downloaded j2ee.jar.zip from http://www.java2s.com/Code/Jar/JKL/
Downloadj2eejar.htm) to the build path in Eclipse-project-properties

12) Only import com.sun.tools.ws.wsdl.document.Output;  is left to correctthe tools.jar from jre/lib is not ok for that.

Downloaded jaxws-tools.jar.zip( 466 k) from http://www.java2s.com/Code/Jar/
STUVWXYZ/Downloadjaxwstoolsjar.htm
and added to the build path in Eclipse-project-properties

13) Downloaded servlet-api.jar.zip( 85 k) from http://www.java2s.com/Code/Jar/STUVWXYZ/Downloadservletapijar.htm

did not help

SET CLASSPATH=.;C:\…..\servlet-api.jar

14) Finally no more errors in project. But no file runs. 404 error for any jsp or java file. Republishing does not help.

Solution – created a new workspace, new dynamic web project, the file by file, and copying previous text into new files. New hibernate configuration, new server jboss 6.0 runtime.

15) New error with import javax.servlet.annotation.WebServlet;

and @WebServlet(“/interf”)

I removed j2ee.jar from the build path.

16) The tables in mysql were already created, so hibernate configurations, reverse engineering importance and jdbc connection problems appeared:

JDBC Driver class not found: com.mysql.jdbc.Driver
JDBC Driver class not found: com.mysql.jdbc.Driver

[STDOUT] empty session for adding quality

 INFO [org.hibernate.connection.DriverManagerConnectionProvider]
cleaning up connection pool: null
 INFO [org.hibernate.connection.DriverManagerConnectionProvider]
cleaning up connection pool: null
 INFO [org.hibernate.connection.DriverManagerConnectionProvider]
cleaning up connection pool: null

17) Indicated the path to the project in eclipse in CLASSPATH

18) Mapping problems: at the string session.save –  Unknown entity

Created again al xml files for each bean, reverse engineering file, hibernate configuration file and put a direct path of the last one in the string writeDB (new File(“…”));

got Unknown entity: beans.qlist

Put also mappings in the configuration file carefully, one by one. Finally it works. So that reading and writing operations with the database are working correctly using hibernate. Hurray.

These are the main steps to restore the previously done project…

Thanks to

1) unix-required labs of

• wireless sensor networks labs;
• concurrency theory project;
• nomadic communications labs;
• network security project;

2) unix installation disk with bug for the “Return” feature button.

Two weeks of future attempts to restore data made my wish to have a faster pc true, as each time the new system is installed, the laptop is quite smart, until there would not be again a lot of programs. So the project I finished worked on in February, was taken as it was sent, not as developed later, unfortunately.

Moreover, it required to install everything from scratch, so my blog was quite useful. I’m so glad to have it!

I have 4 GB of books and things I’ve learnt since October for web architecture. Not counting libraries, distributives, different versions of Eclipse which I still have and enourmous amount of java projects I created and tested (to many places to find at one moment all of them for counting). I really want to put everything in an order. It is very useful and I want to create web applications in my further activity.

“…who wants to live forever”

Also I can’t find how to make posts go in reverse order. It’s like reading a book from the end to the beginning. Oh right, this direction it will have a happy end for sure. So let it be.

Might be EclipseUML Omondoor also Rational or Soyatec.

Or like this one.

And deadline is postponed to 14.02! :)

It was a really big challenge for finding appropriate libraries for my project – connecting jar files into a project, I mean. But now it is fine and looks like 41 jar files taking 14,2 Mb of space. Some of them are already useless I suppose.

Future posts will be not in a good order, I guess.

Nice chapters about authentication and security http://docstore.mik.ua/orelly/java-ent/servlet/ch08_01.htm

Maybe I’ll have time to do registration too.

During these 4 days I had 5 exams, not counting the missed web architecture… I’ll see, how many of them successfully passed.

What I have – knowledge, SQL database accessible from Eclipse using JDBC, somehow connected JSPs with servlets and big plans for future.

http://dev.mysql.com/tech-resources/articles/hierarchical-data.html

I liked it so much. And created my own tables, with 525 beautiful words to use as an example for testing a web application.

.

Downloaded MySQL: mysql-5.5.9-win32.msi from http://www.mysql.com/downloads/.

Using advices from here and from here chosed “complete installiation” and server configuration: “typical”. Suddenly a problem during configuring: an error “Error Nr. 1364 Field ‘authentication_string’ doesn’t have a default value……make sure you have opened the TCP port 3306 for connections…”.

Solution: I turned off firewall and Avira, read about that at the forum “I’d been having the “Can’t connect to MySQL server on localhost (10061)” issue for a couple of days trying to read through the posts here an there on how people solved the issue. Nothing was working for me. Found out I needed to open the port on the windows firewall (Windows NT SP2). But still was having no luck; I opened the port. Still a problem”. An error still appears. Then I decided not to do everything from the beginning, but to go on, using already installed pieces:  Start-all programs-MySql – MySQL server – mysql instance configuration window. This time success.

Then I used command promt and played with databases, users and all that stuff I did 4 years ago…

By the way! :) What a wonderful phrase I found:

“The Windows command line command “net stop beep” will turn off the beeping, and “net start beep” will turn on the beeping.”

And it works!

JDBC:

I started from the tutorial http://www.mastertheboss.com/hibernate/284-hibernate-jboss.html?start=1 for JDBC. And had a lot of errors and problems. In Eclipse: window-Show view-other-Hibernate-Hibernate configurations, open hierarchy by clicking on the “plus”  in that window, and suddenly an error appeared: “Error while opening console configuration. Reason: org.hibernate.console.HibernateConsoleRuntimeException: Problems while loading database driverclass (com.mysql.jdbc.Driver)”.

I found solution from here, downloaded mysql-connector-java-5.1.14.zip, unzipped, in Eclipse chose Project/Properties/JavaBuildPath/Libraries/AddExternalJars , and then chose mysql-connector-java-5.1.14-bin.jar

Now another error… Database in view “Hibernate Configurations” could not be expanded. Instead “Reading schema error: Getting database metadata” appeared.

Created new configuration… “Error while opening Database. The user must supply a JDBC connection” problem.

Did all steps again and carefully from the beginning according to mentioned tutorial, and suddenly I could expand database in Eclipse. Happiness.

Time to model my future application in more details…

The J2EE Trademarked 1.4 Tutorial For Sun Java System Application Server Platform Edition 8.2 ( Eric Armstrong, Jennifer Ball, Stephanie Bodoff, Debbie Bode Carson, Ian Evans, Dale Green, Kim Haase, Eric Jendrock )

At the moment I am trying to make a composition of technologies mentioned earlier.

*1) I have Eclipse Helios:

Eclipse IDE for Java Developers
Version: Helios Service Release 1
Build id: 20100917-0705

*2) I have istalled JBOSS tools in Eclipse.

What do I want to do.

A website, where people can view information and leave some comments about it.

(1) Let’s say, information about people’s characters.

The first part – negative character traits, the second part – positive ones.

Then a visitor can choose the most engaging quality of character from the presented list and to read about it.

(2) Possible to write a comment for this quality.

(3) A possibility of reading other comments.

(4) A possibility to send a message to other visitors

(5) Chance to do a test about each quality.

(6) Chance to  a general test.

(7) Gathering statistics about tests.

(8) Viewing statistics about tests.

(9) Gathering statistics about visitors.

(10) Viewing statistics about visitors.

(11) VIP-person entrance (but no registration)

(12) Opportunity to change text about each quality.

(13) Opportunity to control media related to each quality.

(14) Opportunity to delete or add new qualities in the list.

(15) Contacts page.

1) web tier (implemented using JEE technology), this means any of these technologies can be used

2) business logic tier (implemented using EjB, composed by both stateless and stateful beans) – using Enterprise JavaBeans

3) persistency tier (implemented with a database and accessed through a persistency layer, which must be implemented using Hibernate).

The idea: write java and transform it into Javascript. Debug in “hosted mode”. If your GWT application compiles and runs in hosted mode as you expect, and GWT compiles your application into JavaScript output without complaint, then your application will work the same way in a web browser as it did in hosted mode.

References: Webtoolkit ; List of the widgets ; Demo of the widgets ; two other links for demos of the widgets are no more accessable (page not found)

Google Web Toolkit – cross browser

GWT shields you from worrying too much about cross-browser incompatibilities.

If you stick to built-in widgets and composites, your applications will work similarly on the most recent versions of Internet Explorer, Firefox, and Safari (Opera too, most of the time).

About Google Web Toolkit

Google Web Toolkit Overview

E.g. 174 Web 2.0 Sites in 41 Categories

… and human computing: here is video.

The new web – Examples: demo;  http://demos.openrico.org/ ; school schedule.
More complete  example – A Simpler Ajax Path

Survey of AJAX/JavaScript Libraries
Ext JS Cross-Browser Rich Internet Application Framework
Rich Internet Applications and AJAX – Selecting the best product

Papers about Ajax and architectural description:
Mastering Ajax, Part 1: Introduction to Ajax
Ajax for Java developers: Java object serialization for Ajax
Ajax for Java developers: Ajax with Direct Web Remoting
Ajax for Java developers: Build dynamic Java applications
- all if them are really interesting and have good examples.

60 More AJAX Tutorials

• Entities have a client-visible, persistent identity (the primary key) that is distinct from their object reference.
• Entities have persistent, client-visible state.
• Entities are not remotely accessible.
• An entity’s lifetime may be completely independent of an application’s lifetime.
• Entities can be used in both Java EE and J2SE environments

Examples from the lecture: problem with import javax.persistence.Entity.

1) The JNDI Tutorial ;

2) The JNDI homepage has a list of service providers.

A task from the lecture slides about following some tutorials (Hibernate tutorial and Hibernate in Eclipse) is not valid as these links are already too old and broken.

Instead, I followed the next tutorials:

1) onjava.com

2) hibernate example on eclipse and oracle

3) starting out with spring and hibernate jpa

I liked: Hibernate Getting Started

The Java EE 5 Tutorial
JSTL – xml
JSTL – sql
JSTL – functional tags
JSTL fmt
JSTL by Apache
Open Source JSP Tag Libraries by JavaSource.net

Beans in JSP
JSP Expression Language

MVC with Servlets and JSP – here is an example the Bank Balance lookup (slide 30-42)

The same thing with quotes.
Useful link from the lecture: Introduction To Enterprise Java Bean(EJB)
Problem: Even having JBOSS installed, there is no option in eclipse to choose creating new session bean. Solution: with help of this tutorial I understood my problem and installed JBoss Application Server (jboss-as-distribution-6.0.0.Final.zip). Before I had JBPM but also not installed correctly.

Lecture 17 – Enterprise JavaBeans Patterns slides.

EJB patterns can be found here: J2EE Patterns

Rhino is an open-source implementation of JavaScript written entirely in Java. It is typically embedded into Java applications to provide scripting to end users.

Standard ECMA-262 ECMAScript Language Specification

Books:

• D.Flanagan  “Javascript. The definitive guide” O’Reilly.
• D.Goodman “Dynamic HTML. The definitive reference” O’Reilly

LiveConnect - a two-faced technology to let JavaScript interact with Java, so that:

• A JavaScript script can control and coordinate Java applets, and let Java applets interact with plugins.
• A Java Applet can execute JavaScript code.

LiveConnect Overview
Java-to-Javascript Communication

This WTP Tutorial has useful information also.

According to the lecture slides then

Dispatching, monitoring, filtering

Dispatching example – there was need to change a bit the program. So the code of FirstServlet is:

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.RequestDispatcher;

 public class FirstServlet extends HttpServlet  {
public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException,ServletException {
 PrintWriter out=res.getWriter();
 out.print("First Servlet Called");
 ServletConfig config = getServletConfig();
 ServletContext cntx = config.getServletContext();
 RequestDispatcher dispatch =   
 cntx.getRequestDispatcher("/SecondServlet");
 dispatch.forward(req,res);
}
}

And the second servlet:

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.org.apache.xml.internal.serialize.Printer;
 public class SecondServlet extends HttpServlet  {
 public void doGet(HttpServletRequest req,HttpServletResponse res)  
 throws IOException,ServletException {
 PrintWriter out=res.getWriter();
 System.out.println("Second Servlet Called");
 }
}

When the server was restarted, while calling http://localhost:8080/servletsinlecture/FirstServlet the output “Second Servlet Called” in Console view appears. So it works.

Monitoring

I didn’t actually get example from the lecture 12 ( slides), but this topic is easy.

This example is from a nice tutorial:

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class SimpleCounter extends HttpServlet {

int count = 0;

public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/plain");
PrintWriter out = res.getWriter();
count++;
out.println("Since loading, this servlet has been accessed " +
count + " times.");
}
}

And it perfectly works.

Filtering

A link (lecture 12  slides ) is old for filters in the lecture. And there are many errors in example (such as mistyping req instead of request as parameter’s name was given first time and so on), and there is no full example, such a pity. Only the main idea was indicated. However this example is perfect. Checked.

Tag Extension

This tutorial is good

JSP

The next links were provided in the lecture 12 slides:
Tag Libraries Tutorial ; Java Server Page Tutorial.

Forms

Tested from lecture number 6 slides: in the servlet example ShowParameters one missed comma and one wrong pair of _”_ were found. Example also works good, if manually set parameters in the browser. The expanded version of examples can be found here.

Sending data from html file to servlet works correctly.

Color changer example works in IE with a warning about security.

In “Scrivi li tuo nome” form example few wrong pairs of _”_ were found. The next three examples are fine.

This is a recommended link from the lecture is about reading parameters, this one was also recommended.
This one is an example of a choice based on the HTTP header.

Mimetypes

Examples are in courses.coreservlets(pdf), as provided in the lecture slides.
- How to generate an excel sheet
- How to generate a jpeg on the flight

Sessions

An example in the lecture 12 slides ShowSession is clear and quite accurate, I start thinking that some program (maybe Word) just automatically changes ” to the wrong symbol in a special place, and somehow replaces double brackets “))” to one “)”. But maybe not and those symbols are omitted with a special purpose from the origin.

These are useful links for studying about it:
Java Servlet Programming book
Servlet Tutorial Session Tracking

Cookies:

A link from the lecture 12: code to check if the client accepts cookies. In example SetCookies directly in the slides again a couple of ” was wrong and one round bracket lost. In ShowCookies absolutely the same mistypes were found. Example is workable and gives nice pictures and tables with cookies.

I found a nice website with accurate and clear examples:

• Servlet
  • Get servlet parameters
  • Servlet with no args
  • Set a Cookie from a servlet
  • Read a Cookie from a servlet
  • Delete a Cookie from a servlet
  • Ask a password from a Servlet
  • Talk to a Servlet/JSP from an Applet
  • Test for Cookies support
  • Display ResultSet data in an HTML Table in Servlet
  • Specify the filename to be used for a file sent by a Servlet
  • Pass information to another servlet/jsp
  • Handle PDF output
  • Detect if a connection is secured
  • In a Servlet, check if Form Field is present
  • Get the root dir of a web app
• JSP
  • Get Client IP from JSP
  • Binary output from a JSP
  • Use a connection cache from JSP
  • Read a web application property
  • Use EJB from JSP
  • Define a method in a JSP page
  • Precompile JSP page
  • Get a list of directories from JSP
  • Use and share a class in JSP pages
  • Get the root dir of a web app
  • Launch an applet from a JSP
  • Prevent caching of a JSP output
  • Launch an external program, capture its output and display it in a JSP
• EJB
  • Call another EJB
• BEA WLS
  • Keep java files generated from JSP (BEA WLS)
  • Get the server version (BEA WLS)
  • Quickly create a Web application with BEA WLS
  • Nicely display WEB.XML informations
  • Reverse the CLASSLOADER order (BEA)
  • Detect change in JSP and recompile (BEA)
  • Obtain a remote connection to a DataSource or EJB (Weblogic)

  Java beans: Questions and Answers – Web Tier – from the lecture link. Another one: Introduction to the JavaBeans API: Short Course

I followed the next tutorials:

• Hello World for RMI in Java 6
• The RMI trail in the Java Tutorial

In this book there is a chapter about Securing Web Services.

This book is really helpful to understand the principles.

The two main types of SOAP messages are those that have attachments and those that do not.

The SAAJ APIs extend their counterparts in the org.w3c.dom package:

Moreover, the SOAPPart of a SOAPMessage is also a DOM Level 2 Document and can be manipulated as such by applications, tools, and libraries that use DOM. For details on how to use DOM documents with the SAAJ API, see Adding Content to the SOAPPart Object and Adding a Document to the SOAP Body.

The examples are fully presented in the book.

JAX-RPC = Java API for XML-Based RPC:

The Web Services Messaging with JAXM (JAXM) provides a standard way to send XML documents over the Internet from the Java platform. It is based on the SOAP 1.1 and SOAP with Attachments specifications, which define a basic framework for exchanging XML messages. JAXM can be extended to work with higher level messaging protocols, such as the one defined in the ebXML (electronic business XML) Message Service Specification, by adding the protocol’s functionality on top of SOAP.

This book is really helpful to understand the principles.

An XML registry is an infrastructure that enables the building, deployment, and discovery of web services. It is a neutral third party that facilitates dynamic and loosely coupled business-to-business (B2B) interactions. A registry is available to organizations as a shared resource, often in the form of a web-based service.

Currently there are a variety of specifications for XML registries. These include

A registry provider is an implementation of a business registry that conforms to a specification for XML registries.

JAXR enables Java software programmers to use a single, easy-to-use abstraction API to access a variety of XML registries. A unified JAXR information model describes content and metadata within XML registries.

JAXR gives developers the ability to write registry client programs that are portable across various target registries. JAXR also enables value-added capabilities beyond those of the underlying registries.

The high-level architecture of JAXR consists of the following parts:

Some example with JWSDP.

And a pleasant tutorial Using Message Security with Java WSDP.

JAX-WSA = Java API for XML Web Services Addressing.

This is a nice presentation called “Java API for XML Web Services”.
Specifications of JAX-WSA can be found here.

JAX-WS = Java API for XML Web Services. JAX-WS is an API for creating as well as invoking web services. It succeeds the JAX RPC API and makes it easier by reducing the XML configurations.

Few samples and two useful links:

1) A really good tutorial;

2) Package org.simpleframework.xml description.

Just a lot of work to do.

P.S. I’m going home tomorrow, so I don’t know how often the future activity in my blog will be.

• XLink defines a standard way of creating hyperlinks in XML documents.

• XPointer allows the hyperlinks to point to more specific parts (fragments) inthe XML document.

Example from lecture XLink – simple:

XLink - simple
<?xml version="1.0"?>
<homepages xmlns:xlink="http://www.w3.org/1999/xlink">
<homepage xlink:type="simple"
xlink:href="http://www.w3schools.com">Visit
W3Schools</homepage>
<homepage xlink:type="simple"
xlink:href="http://www.w3.org">Visit W3C</homepage>
</homepages>

From the website at w3schools.com description of this example:

To get access to the XLink attributes and features we must declare the XLink namespace at the top of the document.

The XLink namespace is: “http://www.w3.org/1999/xlink”.

The xlink:type and the xlink:href attributes in the <homepage> elements define that the type and href attributes come from the xlink namespace.

The xlink:type=”simple” creates a simple, two-ended link (means “click from here to go there”). We will also look at multi-ended (multidirectional) links. XLink is getting more interesting when we want to access remote locations as resources, instead of standalone pages. The element in the example above sets the value of the xlink:show attribute to “new”. This means that the link should open in a new window. We could have set the value of the xlink:show attribute to “embed”. This means that the resource should be processed inline within the page. When you consider that this could be another XML document and not just an image, you could, for example, build a hierarchy of XML documents.

With XLink, you can also specify WHEN the resource should appear. This is handled by the xlink:actuate attribute. xlink:actuate=”onLoad” specifies that the resource should be loaded and shown when the document loads. However, xlink:actuate=”onRequest” means that the resource is not read or shown before the link is clicked. This is very handy for low-bandwidth settings.

And then about XPointer syntax:

In HTML, we can create a hyperlink that either points to an HTML page or to a bookmark inside an HTML page (using #).

Sometimes it is more useful to point to more specific content. For example, let’s say that we want to link to the third item in a particular list, or to the second sentence of the fifth paragraph. This is easy with XPointer.

If the hyperlink points to an XML document, we can add an XPointer part after the URL in the xlink:href attribute, to navigate (with an XPath expression) to a specific place in the document.

For example, in the example below we use XPointer to point to the fifth item in a list with a unique id of “rock”:

href="http://www.example.com/cdlist.xml#id('rock').child(5,item)"

Further – presentation of an example about how to use XPointer in conjunction with XLink to point to a specific part of another document.

Here a short version is placed.

Very good description is presented at Cafe con Leche.

The starting point were lecture 5 slides.

The next links were given:

1) List of XPath, XQuery and XSLT functions at w3schools.com,

2) Nice presentation of XPath with examples.

XQuery:

3) http://www.brics.dk/~amoeller/XML/querying/index.html – exactly from the one of my favourite books.

XQuery API for Java:

4) An XQJ Tutorial: Introduction to the XQuery API for Java – “cosi cosi”

5) A very good tutorial at ibm.com, I should try it.

Xquery engines:

6) http://www.sqlsummit.com/XQueryProv.htm#Engine (a very long list, no sense to check each point).

There is an example in lecture slides, the next one:

import java.io.IOException;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import javax.xml.parsers.*;
import javax.xml.xpath.*;
public class XPathExample {
public static void main(String[] args)
throws ParserConfigurationException, SAXException,
IOException, XPathExpressionException {
//read an XML file into a DOM Document
DocumentBuilderFactory domFactory=
DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true); // never forget this!
DocumentBuilder builder = domFactory.newDocumentBuilder();Document
doc =
builder.parse("books.xml");

// prepare the XPath expression
XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
XPathExpression expr
= xpath.compile("//book[author='Dante Alighieri']/title/text()");
//evaluate the expression ona Node
Object result = expr.evaluate(doc, XPathConstants.NODESET);
// examine the results
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
System.out.println(nodes.item(i).getNodeValue());
}
}
}

It works great. Just one last bracket was lost. The file books.xml should be in the same folder as this java class.

So tested and carefully read almost all recommended materials.

JAXB is the official API for XML binding from Sun:

• supports binding of DTD and XML Schema
• allows customization of the binding
• standardizes the interfaces for the generated classes
• allows different JAXB implementations to use different implementations of these interfaces
• supports validation of unmarshalled documents
• supports validation of content trees
• is unrelated to DOM and JDOM

I understood what is marshalling and unmarshaling, why is it used for.

This article is good. Here is quite short introduction to JAXB, and here it is connected with JBOSS.

I should pay attention again to this article, as I didn’t understand anything in it.

From the lecture 4 slides: “JAXP provides a common interface for creating and using the standard SAX, DOM, and XSLT APIs in Java, regardless of which vendor’s implementation is actually being used”.

And yes, that’s true.

Let this post be a kind of summary on JAXP.

Useful: jaxp.java.net

1) jdom.org

2) dom4j.org

From the first one from http://www.jdom.org/dist/binary/ downloaded jdom-1.1.1.zip, jdom-contrib-1.1.1.zip and jdom-test-1.1.1.zip.

Also faq was useful.

The second link has more advertisements than new information.

Nice tutorial at the coffee machine blog provided an opportunity to work with xml file and create a new one.

First of all I unzipped jdom-1.1.1.zip, then in eclipse-java project-properties in build path added external jar from jdom-1.1.1/build/jdom.jar.
With help of the class JDOMDVD an output dvd.xml was successfully created. The other two examples (JDOMDVDTitles and JDOMDVDFilter) were also runned successfully. An interesting point was using JFileChooser, which makes working more pleasant even already being in eclipse.

Nice example at brics.dk – A Business Card editor.

Remembering about a source with using recipes.xml file, the main idea was underlined:
“DOM is too complicated to suit many programmers. Since it is a general API, it does not use special Java features – for example, existing collection classes are ignored. JDOM is designed to be simple and Java-specific. “
Example was checked (FirstRecipeJDOM), the source codes can be found here. And the information on that website is always short and clear.

Then I turned back to my favourite book and tested all examples in the appropriate chapter 14. Very nice. I learned a lot.

1) book

2) slides

Nice post about TrAX is presented here – XML Processing with TRaX. There are also examples.

By the way, a new source of handy materials was found.

• JAXP/XPath example – I
• JAXP/XPath example – II
• JAXP/XPath example – III

Problem. First time when started, the next error after the correct output in colsole appeared:

ERROR: JDWP Unable to get JNI 1.2 environment, jvm->GetEnv() return code = -2
JDWP exit error AGENT_ERROR_NO_JNI_ENV(183): [../../../src/share/back/util.c:820]

All next times and further playings it didn’t give such error.

Here is java code:

import java.io.IOException;
import javax.swing.text.Document;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.NodeList;
import org.w3c.dom.xpath.XPathExpression;
import org.xml.sax.SAXException;

public class domm {
	public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {

	DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
	factory.setNamespaceAware(true); // never forget this!
	DocumentBuilder builder = factory.newDocumentBuilder();
	org.w3c.dom.Document doc = builder.parse("books.xml");
	XPathFactory factory1 = XPathFactory.newInstance();

	//Now we have to use this factory to create an XPath object:

	XPath xpath = factory1.newXPath();

	//The XPath object compiles the XPath expression:

	javax.xml.xpath.XPathExpression expr = xpath.compile("//book[author='Neal Stephenson']/title/text()");

	//Finally, we will evaluate the XPath expression to get the result using evaluate(…) method.

	Object result = expr.evaluate(doc, XPathConstants.NODESET);

    //Now you can cast the result to a DOM NodeList and iterate through that to find all the titles as shown below:

	NodeList nodes = (NodeList) result;
	for (int i = 0; i < nodes.getLength(); i++) {
	    System.out.println(nodes.item(i).getNodeValue());
	}
	}
}

And example of code of books.xml

<inventory>
 <book year="2000">
 <title>Snow Crash</title>
 <author>Neal Stephenson</author>
 <publisher>Spectra</publisher>
 <isbn>0553380958</isbn>
 <price>14.95</price>
 </book>

 <book year="2005">
 <title>Burning Tower</title>
 <author>Larry Niven</author>
 <author>Jerry Pournelle</author>
 <publisher>Pocket</publisher>
 <isbn>0743416910</isbn>
 <price>5.99</price>
 </book>

 <book year="1995">
 <title>Zodiac</title>
 <author>Neal Stephenson</author>
 <publisher>Spectra</publisher>
 <isbn>0553573862</isbn>
 <price>7.50</price>
 </book>

 <book year="1905">
 <title>Some Name</title>
 <author>Neal Stephenson</author>
 <publisher>Publisher2</publisher>
 <isbn>0511173862</isbn>
 <price>1.10</price>
 </book>
 <!-- more books... -->

</inventory>

The output:

Snow Crash
Zodiac
Some Name

- Correct, as these are all the names of Neal Stephenson’s books in .xml file.

By the way, a set of good lessons can be found here http://www.dickbaldwin.com/tocxml.htm

Reading the information and testing a good example (program that uses JAXP to check documents for well-formedness) from Cafe con Leche website.

import javax.xml.parsers.*; // JAXP
import org.xml.sax.SAXException;
import java.io.IOException;

public class JAXPChecker {

  public static void main(String[] args) {

    if (args.length <= 0) {
      System.out.println("Usage: java JAXPChecker URL");
      return;
    }
    String document = args[0];

    try {
      DocumentBuilderFactory factory
       = DocumentBuilderFactory.newInstance();
      DocumentBuilder parser = factory.newDocumentBuilder();
      parser.parse(document);
      System.out.println(document + " is well-formed.");
    }
    catch (SAXException e) {
      System.out.println(document + " is not well-formed.");
    }
    catch (IOException e) {
      System.out.println(
       "Due to an IOException, the parser could not check "
       + document
      );
    }
    catch (FactoryConfigurationError e) {
      // JAXP suffers from excessive brain-damage caused by
      // intellectual in-breeding at Sun. (Basically the Sun
      // engineers spend way too much time talking to each other
      // and not nearly enough time talking to people outside
      // Sun.) Fortunately, you can happily ignore most of the
      // JAXP brain damage and not be any the poorer for it.

      // This, however, is one of the few problems you can't
      // avoid if you're going to use JAXP at all.
      // DocumentBuilderFactory.newInstance() should throw a
      // ClassNotFoundException if it can't locate the factory
      // class. However, what it does throw is an Error,
      // specifically a FactoryConfigurationError. Very few
      // programs are prepared to respond to errors as opposed
      // to exceptions. You should catch this error in your
      // JAXP programs as quickly as possible even though the
      // compiler won't require you to, and you should
      // never rethrow it or otherwise let it escape from the
      // method that produced it.
      System.out.println("Could not locate a factory class");
    }
    catch (ParserConfigurationException e) {
      System.out.println("Could not locate a JAXP parser");
    }

  }

}

The output:
“MyF.xml is well-formed.”
And an option “validate” is already built in eclipse – just right-mouse click on the .xml file and then “Validate”.
As we know from the second lecture (XML), XML documents need not be valid, but all XML documents must be well- formed.

Just a magical book – Processing XML with Java by Elliotte Rusty Harold. So clear, so accurate, so pleasant to read and to work with its material.

Starting form the lecture 4 slides. The example for SAX which consists of two classes can not be just pasted into eclipse, there should be “public class Echo01 {” without “implements MySaxHandler”. Then it works.

The output for MyFile.xml described in previous post was:

<?xmlversion='1.0' encoding='UTF-8'?>
<student>
 <student-name>
 <firstname>
 </firstname>
 <lastname>
 </lastname>
 </student-name>
 <student-address>
 <address>
 </address>
 <city>
 </city>
 </student-address>
</student>

Tthen going to saxproject website and finding good links.

Continuing working with <a href=”http://www.brics.dk/~amoeller/XML/programming/saxapi.html”>this page</a> and its <a href=”http://www.brics.dk/~amoeller/XML/programming/saxexample.html”>example</a> about recipes collection.
The first example Flour gave error:
“[Fatal Error] recipes.xml:2:1: Content is not allowed in prolog.
org.xml.sax.SAXParseException: Content is not allowed in prolog.
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at Flour.main(Flour.java:25)
0.0″
The last extended example Trace with SAX events gives strange message in eclipse:
“start document
processing instruction: dsd
[Fatal Error] recipes.xml:2:1: Content is not allowed in prolog.
org.xml.sax.SAXParseException: Content is not allowed in prolog.
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at Flour.main(Flour.java:55)”

Like with DOM example I still don’t now what to do with that, however the code is quite clear.

The next example I took from here, where SAXParserFactory class is used. It works.

Also I read a clear tutorial about SAX from a given link from the lecture. It’s interesting, highly recommended.

“XML Exercise

You are given a xml file that contains the description of a person. You are requested to write java code to parse it using the available java for xml tools, and to create an object of class Person having two instance variables (name and age) that have to be populated by using the info available in the xml file.
Here is a solution provided by Jouke (one of your colleagues).
As a next tep you should code the viceversa (i.e. start from an instance of Person and produce a xml file that serializes its state).
You are then invited to think how this can be generalized to arbitrary classes, having an arbitrary number of instance variables. (Suggestions: provide a getter and setter method for every instance variable, and use Class.forName(), Class.getMethod() and Method.invoke(). To know more about these methods and their usage, look at the Java Reflection API tutorial and in particular at the sections about retrieving Class objects and method invokation
Note: To pass primitive values, you have to wrap them in the corresponding Object type. E.g. to call a method taking an “int”, via reflection, you have to do the actual call as follows: setIdMethod.invoke(obj, new Object[]{new Integer(5)});
Also, please take a look at some slides that show a framewok that was designed to use XML to serialize/deserialize Java objects.”

The solution works in eclipse and consists of three files:  PersonParser.java, Person.java, Person.xml.
Person.xml:

<class><name>Person</name>
<attributes>
 <field>
 <type>int</type>
 <name>age</name>
 <value>13</value>
 </field>
 <field>
 <type>String</type>
 <name>name</name>
 <value>Nicole</value>
 </field>
</attributes>
</class>

PersonParser.java file:

import java.io.*;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import javax.xml.xpath.*;

public class PersonParser {
 public static void main(String[] args) throws Exception {
 File file = new File("person.xml");

 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 DocumentBuilder db = dbf.newDocumentBuilder();
 Document doc = db.parse(file);

 XPathFactory factory = XPathFactory.newInstance();
 XPath xpath = factory.newXPath();
 XPathExpression expr = xpath.compile("/class[name/text()='Person']/attributes//field");
 XPathExpression exprType = xpath.compile("./type/text()");
 XPathExpression exprName = xpath.compile("./name/text()");
 XPathExpression exprValue = xpath.compile("./value/text()");

 Person p = new Person();

 NodeList nodes = (NodeList)expr.evaluate(doc, XPathConstants.NODESET);
 for (int i = 0; i < nodes.getLength(); i++) {

 String type = ((Node)exprType.evaluate(nodes.item(i), XPathConstants.NODE)).getNodeValue();
 String attributeName = ((Node)exprName.evaluate(nodes.item(i), XPathConstants.NODE)).getNodeValue();
 String value = ((Node)exprValue.evaluate(nodes.item(i), XPathConstants.NODE)).getNodeValue();

 p.setAttribute(attributeName, type, value);
 }

 System.out.println(p);
 }
}

Person.java file:

import java.io.Serializable;

public class Person implements Serializable{

 int age;
 String name;

 public Person(){
 this.name = null;
 this.age = 0;
 }

 public void setAttribute(String attributeName, String type, String value) throws Exception{
 if(attributeName.equals("age") && type.equals("int")){
 this.age = Integer.parseInt(value);
 } else if(attributeName.equals("name") && type.equals("String")){
 this.name = value;
 } else {
 throw new Exception("Invalid input");
 }
 }

 public String toString(){
 return "<Person age=" + this.age + " name=" + this.name + ">";
 }
}

Three files (notes.dtd, notes.xml, notes.xsd) from the example of XML Schema from here were added to the project, and with help of the information at the web-page about validation in eclipse I selected three files and right-mouse clicked “Validate”. A new message appeared: “The validation completed with no errors or warnings”.  Success. Few more things about validation.

This is a good description of XML Schema with an example about business cards.

Example of a complex type:

<complexType name="order_type" mixed="true">
  <choice>
    <element ref="n:address"/>
    <sequence>
      <element ref="n:email" minOccurs="0" maxOccurs="unbounded"/>
      <element ref="n:phone"/>
    </sequence>
  </choice>
  <attribute name="id" type="unsignedInt" use="required"/>
</complexType>

Another detailed resource on this topic can be found here.
And a whole book dedicated to XML Schema with clear examples presents the next chapters:

Chapter 1: Schema Uses and Development
Chapter 2: Our First Schema
Chapter 3: Giving Some Depth to Our First Schema
Chapter 4: Using Predefined Simple Datatypes
Chapter 5: Creating Simple Datatypes
Chapter 6: Using Regular Expressions to Specify Simple Datatypes
Chapter 7: Creating Complex Datatypes
Chapter 8: Creating Building Blocks
Chapter 9: Defining Uniqueness, Keys, and Key References
Chapter 10: Controlling Namespaces
Chapter 11: Referencing Schemas and Schema Datatypes in XML Documents
Chapter 12: Creating More Building Blocks Using Object-Oriented Features
Chapter 13: Creating Extensible Schemas
Chapter 14: Documenting Schemas
Chapter 15: Elements Reference Guide
Chapter 16: Datatype Reference Guide
Appendix A: XML Schema Languages
Appendix B: Work in Progress
Glossary
Index

Here is a good description of DOMParser.

Starting from lecture 4 JAXP slides and reading information at w3.org I found resource the Open Directory Project W3C DOM pages and then Apache DOM Implementation in Java I understood the idea and principles of DOM.

Example CountDom in lecture is workable, but there is one extra bracket. It should be organized this way:

import java.io.*;
import org.w3c.dom.*;
import org.xml.sax.*;   // parser uses SAX methods to build DOM object
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
public class CountDom {
public static void main(String[ ] arg) throws Exception {
if (arg.length != 1) {
System.err.println("Usage: cmd filename (file must exist)");
System.exit(1);
}
Node node = readFile(new File(arg[0]));
System.out.println(arg + " elementCount: " + getElementCount(node));
}

public static Document readFile(File file) throws Exception {
Document doc;
try {
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setValidating(false);
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(file);
return doc;
} catch (SAXParseException ex) {
throw (ex);
} catch (SAXException ex) {
Exception x = ex.getException();   // get underlying Exception
throw ((x == null) ? ex : x);
}
}
public static int getElementCount(Node node) {
if (null == node)      return 0;
int sum = 0;
boolean isElement = (node.getNodeType() == Node.ELEMENT_NODE);
if (isElement)  sum = 1;
NodeList children = node.getChildNodes();
if (null == children)       return sum;
for (int i = 0; i < children.getLength(); i++) {
sum += getElementCount(children.item(i));   // recursive call
}
return sum;
}
}

Result for xml-document MyFile.xml, which I pointed in program arguments in eclipse-run-run configurations is the next:
[Ljava.lang.String;@1bac748 elementCount: 7
MyFile.xml text:

<?xml version="1.0"?>
<student>
<student-name>
<firstname>Anusmita</firstname>
<lastname>Singh</lastname>
</student-name>

<student-address>
<address>Rohini</address>
<city>Delhi</city>
</student-address>
</student>

As that example was not enough for me (its variations I found here), I tried an example from here (a simple DOM example). Temporary problem - could not resolve import org.apache.xerces.parsers.DOMParser. Solution - to add in elcipse-project-build path-add extern jar - jars form Xalan folder. So just having them in CLASSPATH is not enough. However an error "java.lang.ArrayIndexOutOfBoundsException: 0
at FirstRecipeDOM.main(FirstRecipeDOM.java:11)" appeared. The code is fully understandable, but the reason of exception - not. Later another kind of error appeared:
"[Fatal Error] recipes.xml:2:1: Content is not allowed in prolog.
org.xml.sax.SAXParseException: Content is not allowed in prolog.
at org.apache.xerces.parsers.DOMParser.parse(Unknown Source)
at FirstRecipeDOM.main(FirstRecipeDOM.java:11)”

After that fail I found another set of examples at ibm.com website. Running TestDOMParsing for MyFile.xml the result was:
“Warning: validation was turned on but an org.xml.sax.ErrorHandler was not
set, which is probably not what is desired. Parser will use a default
ErrorHandler to print the first 10 errors. Please call
the ‘setErrorHandler’ method to fix this.
Error: URI=file:/C:/eclipseHelios/workspace/projx/MyFile.xml Line=2: Document root element “student”, must match DOCTYPE root “null”.
Error: URI=file:/C:/eclipseHelios/workspace/projx/MyFile.xml Line=2: Document is invalid: no grammar found.”
However the best tutorial is this one. I went through all its lessons using eclipse:

1. Creating Blank DOM Document
   This section shows you how to create the blank DOM document.
   
2. Adding Child Elements to the DOM tree
   This lesson shows you how to create root and child elements in the DOM tree.
3. Getting The XML Root Element
   After reading this section, you will be able to retrieve a  root element from the XML document.  The JAXP (Java APIs for XML Processing) provides a common interface for creating and using xml files using the standard SAX, DOM and XSLTs.
   
4. To Count XML Element
   In this section, you will learn to count the elements present in a  XML file using DOM APIs.
   
5. To Count The Elements in a XML File
   In this section, you will learn to count the element in XML document using DOM APIs defined in the org.apache.xerces.parsers.DOMParser package.
   
6. XML Well-Formed-ness
   In this section, you will learn to check the well-formed-ness  of a XML using the DOM interface. A  well-formed  XML  document must follow the xml syntax rules.
7. Searching an Element in the given XML Document
   In this you will learn to search an element in the specified XML document using DOM APIs defined in the org.apache.xerces.parsers.DOMParser package.
   
8. Create – XML File (Document)
   In this section, you will  learn to create a XML document using the DOM APIs. This XML document uses  1.0 version  and UTF-8 encoding.
9. Regenerating XML  file
   In this section, you will learn to get the  elements and its value using DOM APIs.
10. XML Error checker and locater (DOM)
    In this section, you will learn to check and locate (line and column number) an error in your XML document using the DOM APIs.  The XML document follows some rules to check its syntax.
    
11. Getting all XML Elements
    In this section, you will learn to retrieve all elements of the XML file using the DOM APIs. This APIs provides some constructors and methods which helps us to parse the XML file and retrieve all elements.
    
12. Adding DOCTYPE to a  XML File
    In this section, you will learn to add a DOCTYPE to your XML file  using the DOM APIs.
    
13. Getting Dom Tree Elements and their Corresponding XML Fragments
    In this section, you will learn to get the elements of a DOM tree and their corresponding XML fragments. Each element of dom tree has a node level starting with ’0′. Here the DOM tree elements and their corresponding XML fragments are displayed on the console.
    
14. Cloning a XML Element
    In this section, you will learn to create a clone of a  element in the DOM tree. In general, the cloning means to create a duplicate.
    
15. Remove Element from XML Document
    In this section, you will learn to remove any element from a given  XML document. Whenever you remove the xml element from the xml document the data are also lost from the xml element.
    
16. Getting Data from XML File (Document)
    In this section, you will learn to retrieve the data from a XML file. All xml files store the data. You can add and modify the data in the  xml document using the DOM APIs.
    
17. Storing Data (Retrieved from a XML Document) to a File
    In this section, you will learn to store data (retrieved from the XML document) to a specified file (with  extension ‘.txt’, ‘.doc‘, ‘.xls‘, ‘.shtml‘ etc.) in different formats (text, xml, html etc.).
    
18. XML Validate DTD
    In this section, you will learn to validate a xml file against a  DTD (Document Type Definition)  using the DOM APIs. A DTD defines  the document structure with a list of legal elements and attributes.
    
19. Accessing XML file from Java
    In this example we have provided you a simple java example with the source code that will make it possible to access the XML file through Java. For that we have used DOM parser.

And I liked it very much. Yes, there are some mistakes in codes, however they are so easy – like forgotten bracket or another kind of import. However each of them was successfully tested.

Also Cafe con Leche and devx.comprovide nice examples.

I tried to use this technology

According to the good tutorial at http://www.vogella.de/articles/DocBook/article.html and went through all its steps.

Buildfile: C:\eclipseHelios\workspace\de.vogella.docbook.first\build.xml

depends:

build-html:

[xslt] Transforming into C:\eclipseHelios\workspace\de.vogella.docbook.first\output

[xslt] Processing C:\eclipseHelios\workspace\de.vogella.docbook.first\documents\book.xml to C:\eclipseHelios\workspace\de.vogella.docbook.first\output\book.html

[xslt] Loading stylesheet C:\eclipseHelios\workspace\de.vogella.docbook.first\docbook-xsl\html\docbook.xsl

BUILD SUCCESSFUL

Total time: 4 seconds
Files in folder docbook-xml were downloaded from here.

Also there is a possibility to use Eclipse XSL Developer Tools, then the process can be simplified, and the tutorial http://www.vogella.de/articles/XSLT/article.html will help.

This book provides a good description and shows how to use it:

Sample XSP Page

<?xml version="1.0"?>
<?cocoon-process type="xsp"?>
<?cocoon-process type="xslt"?>
<?xml-stylesheet href="myStylesheet.xsl" type="text/xsl"?>

<xsp:page language="java"
 xmlns:xsp="http://www.apache.org/1999/XSP/Core"
>

 <xsp:logic>
 private static int numHits = 0; 

 private synchronized int getNumHits(  ) {
 return ++numHits;
 }
 </xsp:logic>

 <page>
 <title>Hit Counter</title>

 <p>I've been requested <xsp:expr>getNumHits(  )</xsp:expr> times.</p>
 </page>
</xsp:page>

XSL Stylesheet for it:

<?xml version="1.0"?>

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>

 <xsl:template match="page">
 <xsl:processing-instruction name="cocoon-format">
 type="text/html"
 </xsl:processing-instruction>
 <html>
 <head>
 <title><xsl:value-of select="title"/></title>
 </head>
 <body>
 <xsl:apply-templates select="*[not(self::title)]" />
 </body>
 </html>
 </xsl:template>

 <xsl:template match="p">
 <p align="center">
 <xsl:apply-templates />
 </p>
 </xsl:template>

</xsl:stylesheet>

Thus, XSP easily handles the first major problem of JSP: it allows the separation of content from presentation. This separation allows developers to handle content generation (as the XSP page can be generated from a servlet or other Java code as well as being static), while XML and XSL authors can handle presentation and styling through modification of the XSL stylesheet applied to the XSP page. Just as easily, XSP solves the other significant deficiency of JSP: because XSP processing occurs before any stylesheets are applied, the resultant XML document can be transformed into any other format. This maintains all the advantages of XML, as the XSP page can be transferred between applications as well as being used just for presentation.

The other chapters:

Web Publishing Frameworks
Selecting a Framework
Installation
Using a Publishing Framework
XSP
Cocoon 2.0 and Beyond
What’s Next?

Having installed elipse and tomcat, finally the Dynamic Web Project was created in eclipse, target runtime was set as Apache Tomcat 5.5, file index.jsp was added to the project, in the view “Servlets” new server was added – tomcat 5.5 and the current project was added to it. In this view still right-click on Tomcat – start, then right-click – publish. Successfully! So the server is started, and the project is linked. Then I just open the page http://localhost:8080/TEcl/index.jsp and see wonderful sentence “Today’s date is Tue Dec 14 19:45:35 CET 2010 and this jsp page worked!”. And each time I renew the page in the browser, in eclipse a string “Evaluating date now” in view Console appears.
index.jsp:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>My Title</title>
</head>
<body>
<% java.util.Date d = new java.util.Date(); %>
<h1>
Today's date is <%= d.toString() %> and this jsp page worked!
</h1>
</body>
</html>

Then the next example was tested successfully – a new servlet in this project was created and runned. I liked the following tutorial.

It’s productive to develop JSPs and servlets without having to leave the IDE to start, stop, or deploy to your server. The combination of Eclipse and Apache Tomcat provides an easy integrated environment that enables you to speed up development.

Also links form the lecture were used:

How to use Tomcat 7 with Eclipse (good, however my Tomcat version is 5.5.31)

A recommended from the lecture 6-7 (download) slides very good tutorial about servlets with examples from Duke’s Bookstore application

JEE 6.0 Sevlet API (overview of all classes and packages, very useful)

Beginning & Intermediate Servlet & JSP Tutorials (Building Web Apps in Java)

From the last link also exercises were done, such as
1) Getting Started;

2) Servlets Basics, I learned how to create war file and to test my project on the remote server (with help of this information) but haven’t find appropriate server for testing. And for the student’s project it is enough to show at localhost, so not so necessary. Let’s believe it works. Why not.

Understood what the methods Get and Post are, and as I also read the slides from 2009, tried to understand the pieces of code “A taste of servlet programming-2009″, ineffectively. Tried to expand them into normal program, but too many errors in Eclipse made me understand it is much easier to write my own program from scratch with the same functionality.  That code is a kind of a problem. But configuring with web.xml is always fine.

3) Handling the Client’s request: Form Data, redirecting works, but I created my own example, as they use Tomcat 7, and mine is 5.5.31. The tutorial in PDF is so clear, I liked it very much.

4) Handling the Client’s request: Http request header in PDF

5) Generating the Server Response: HTTP Status Codes in PDF

6) Generating the Server Response: HTTP Response Headers in PDF

7) Handling Cookies  in PDF

8) Session Tracking in PDF

9) JSP Introduction and Overview in PDF

And there are much more attractive lessons at that website, many thanks for a good link, professor.

Now things look like much easier than before.

For doing this JAX-WS (Java API for XML-Web Services) was needed. Unfortunately, Eclipse 3.3.0 is too old for easy installation JBoss.

So a new version of Eclipse was downloaded, Eclipse Helios 3.6.1 (Eclipse IDE for Java Developers, Version: Helios Service Release 1 , Build id: 20100917-0705 ), installed and runned.

Help > Install New Software… > and pointed the next URL:
http://download.jboss.org/jbosstools/updates/development/

Choosed all “Web and Java EE Development” and “All JBoss Tools 3.2.0″. Haven’t read all user agreement texts… Installed. Restarted the PC. After this procedure computer was starting for very long time…

Downloaded last version of JDK (1.6.0_23) and JRE 6 from here.
Problem – java from the command prompt suddenly didn’t work. Information at this webpage and this one helped me to solve the problem (Additional changes in evironment variables: PATH, CLASSPATH, indicating the place of the workspace).
Considering this tutorial everything works.

Finally, examples from the Martin Kalin’s book “Java Web Services: Up and Running” with TimeServerPublusher and TimeClient started working correctly using command prompt .

Also the example with KnockKnockServer and KnockKnockClient successfully worked.

Apache Cocoon

Enhydra Application Server

Bluestone XML Server

SAXON

This book has a nice chapter about using Cocoon.

This is a good text about DTD

This book provides a good description of DTD too.
XML documents (and HTML documents) are made up by the following building blocks:
Elements, Tags, Attributes, Entities, PCDATA, and CDATA.
PCDATA means parsed character data. CDATA also means character data.
On that website there is a possibility to try examples on ourselves. Very useful.

Table of contents:

Introduction to DTD by Jan Egil Refsnes
An introduction to the XML Document Type Definition.

DTD – XML Building Blocks by Jan Egil Refsnes
What XML building blocks are defined in a DTD.

DTD Elements by Jan Egil Refsnes
How to define the elements of an XML document using DTD.

DTD Attributes by Jan Egil Refsnes
How to define the legal attributes of XML elements using DTD.

DTD Entities by Jan Egil Refsnes
How to define XML entities using DTD.

DTD Validation by Jan Egil Refsnes
How to test for DTD errors while loading XML documents.

DTD Examples by Jan Egil Refsnes
Some DTD examples

By the way, Eclipse Setup for XML:
In Eclipse, go to Windows Menu and add the following jars for XML configuration in Eclipse
Window > Preferences > Ant > Runtime >Classpath > Add Jars:
xalan.jar
xercesImpl.jar
xmlParserAPIs.jar  - instead this one I added xml-apis.jar

Eclipse Europa version 3.3.0 was installed, also there is jre v.6 and jdk1.6.0_16.

Lecture 2 – Sept 21 – XML and XSLT

1) Successfully downloaded, installed and runned Tomcat version 5.5.31

( start – run – “cmd” -… “cd tomcat/bin/” – “startup” )
On the request

“http://localhost:8080/”

it is possible to see the start page of Apache Tomcat/5.5.31.

1a) Checked that static pages are serving
Static pages are in the Tomcat Document Root directory:  tomcat\webapps\ROOT.  Running http://localhost:8080/tomcat.gif in browser shows us a picture of a nice cat. The .html files in that directory are also running on the related request http://localhost:8080/helloTrento.html.

Also folder “war” for web arcitecture subject files was created.  The .html file in that directory is running on request http://localhost:8080/war/helloTrento.html.  So Tomcat serves static pages.

1b) Checked that dynamic pages are serving

It is also working, checked by using the link on JSP example “Implicit Objects” in “JSP 2.0 Examples” section (http://localhost:8080/jsp-examples/jsp2/el/implicit-objects.jsp?foo=first) from the start page.

The file helloTrento.jsp was created. Its text, as example :

<HTML>
<BODY>
<%
    // This scriptlet declares and initializes "date"
    System.out.println( "Evaluating date now" );
    java.util.Date date = new java.util.Date();
%>
Hello!  The time is now
<%
    // This scriptlet generates HTML output
    out.println( String.valueOf( date ));
%>
</BODY>
</HTML>

Request http://localhost:8080/war/helloTrento.jsp gives an output “Hello! The time is now Mon Dec 06 12:25:45 CET 2010″
2) Assignment:

• download Apache Xalan – install it – try the example in Xalan-Java Overview
• ZVON XSLT Tutorial
• ZVON Interactive Lab

1) Downloaded and unzipped Xalan version 2.7.1 (bin).
Changed CLASSPATH.
Checked it works using a command in cmd:  java org.apache.xalan.xslt.EnvironmentCheck

PROBLEM number 1) – error “could not find the main class: org.apache.xalan.xslt.EnvironmentCheck”
Solved: the environment variable name was set as CLASS_PATH instead of CLASSPATH.
PROBLEM number 2) – the commands are case  sensitive. So it was NOT correct to use command “java org.apache.xalan.xslt.environmentcheck”

Being in the folder /war/ the next command was used to check the example given in slides:
java   org.apache.xalan.xslt.Process -IN test1.xml –XSL test1.xsl –O out.html

And the word “Process” here has the first capital letter too.

Trying to do the same with example in Xalan-Java Overview

java   org.apache.xalan.xslt.Process –IN foo.xml –XSL foo.xsl –O out.html

PROBLEM – got the error “the process instruction target matching “[xX][mM][lL]” is not allowed.”
Solved: there was an empty raw in the file .xml
A file out.html was created successfully.

3) Checked an example “Selective processing” from the lecture 2 slides

Two symbols were missed: instead of  xmlversion – xml version and one more between xsl:stylesheetxmlns – xsl:stylesheet xmlns.

Using command java ‑ ­ org.apache.xalan.xslt.Process –IN foo.xml –XSL foo.xsl –OUT out.html
File out.html was created:
<?xml version=”1.0″ encoding=”UTF-8″?>
Esiste una parte privata
La parte pubblica contiene:
SEZIONE PUBBLICA
Testo Pubblico

- Successfull.

Lecture 6 – Oct 5 – Servlets
4) Servlets

In Tomcat subdirectory “webapps” inside the folder “war” was created folder “WEB-INF”. Also file web.xml  and a folder “classes” were put in “WEB-INF”.

The file ServletInTrento.java was created in folder “classes”.  Its text:

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class ServletInTrento extends HttpServlet {

public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {

PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>First servlet title</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("Welcome to Trento!");
out.println("This is a first servlet");
out.println("</BODY>");
out.println("</HTML>");
}
}

Compiling .java file:  in command prompt being in folder tomcat/bin “startup”; then “cd war/WEB-INF/”; “javac ServletInTrento.java”. It is necessary to add “tomcat\common\lib\servlet-api.jar” to environment variable CLASSPATH.
ServletInTrento.class was created. Then the file web.xml was modified to let Tomcat serve servlet (the keyword for activating servlet was set as <url-pattern>/runnow</url-pattern>).
To execute the servlet called ServletInTrento the URL was: http://localhost:8080/war/runnow.

The output we got was “Welcome to Trento! This is a first servlet”.

Were given two good links at ZVON. The first one has nice russian version

And the second link ZVON Interactive Lab is very useful to learn and to see all possible opportunities in working with XSL.

Materials were used:

(1) Lectures’ videos and slides XML.pdf ; XSLT.pdf ; Servlets
(2) Java Servlet Technology
(3) How to write HTML forms
(4) Materials at the website w3schools.com
(5) Configuring Tomcat to serve static files
(6) Apache Tomcat – Tutorial
(7) Tomcat – A Minimalistic User’s Guide
(8) Static vs Dynamic content
(9) Static and Dynamic Web content
(10) Web design
(11) Installing an XSLT processor
(12) Example at xml.apache.org
(13) Example for servlet running
(14) Running a Servlet under Tomcat
(15) Servlets and filters
(16) JSP tutorial
(17) JSP examples
(18) A Servlet and JSP Tutorial