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Monday, 19 July 2010

Comments on Applied Numerical Analysis, by Curtis F. Gerald, Patrick O. Wheatley, 3rd Edition

On the bright side, the text is well written in American English with few typographical errors. Its text is full of worked examples, figures, graphs and tables with actual results of approximations. The problems at the end of each chapter help the reader to become familiar with the techniques, in a practical way. There are also computer programs for the reader, to practice, that is reusable source code in c, FORTRAN and for other tools, common nowadays, such as Maple, etc.
On the dark side, there are no proofs of theorems, which are of theoretical interest, especially to the mathematicians.
All in all, the book is a huge success, now at the 7th edition, suitable for engineers, or readers fond of the practical view of mathematics.

Comments on Numerical Solution Of Partial Differential Equations: Finite Difference Methods, 2nd Edition by G.D. Smith, Oxford Press

On the bright side, the text is very well written, in British English, with a few spelling errors. It is quite clear and moderately easy to follow. In addition, the text is full of figures, graphs and worked examples.
On the dark side its second edition, (1977) which I have studied, has no unsolved exercises, problems or any questions to reinforce learning and apply the theoretical techniques. Moreover, the book is not accompanied by any program or source code for tools such as Matlab or Mathematica.
All in all, the book is a success, now in its 3rd edition. Its main readers should be mostly students of mathematics, but not of engineering.

Tuesday, 13 July 2010

Getting the current date in your model layer

Besides the standard way of getting the current date as a String, one could come across the need of inserting in a database table column of date datatype. Thus, the well known code snippet won't be suitable:

 DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
 
 java.util.Date date = new java.util.Date();
 
 String datetime = dateFormat.format(date);
 
 System.out.println("Current Date Time : " + datetime);
 
In case you use ADF business components for your Model project, you get the 
current date in a slightly different way. Consider for example the following code snippet,
from an adf business components, employees entity object: 
 
import oracle.jbo.domain.Date;
...

              
protected void doDML(int operation, TransactionEvent e) {
                if (operation == DML_UPDATE) {
    ...
               histStartDate = row.getEndDate();
              /*Check whether end date equals current date*/
              if (histStartDate.equals(new Date(Date.getCurrentDate()))){
                  System.out.println("End date equals current date!");
                  }
      
In case you need to convert  oracle.jbo.domain.Date to java.util.Date, please consult this:

http://forums.oracle.com/forums/thread.jspa?threadID=2185902&tstart=15

or

http://www.ecotronics.ch/webdesign/javadate.htm
  

Finally, in case you prefer EJB's for your Model project instead, you might consider the following example:

/*Typical current date for DB inserts */
java.util.Date today = new java.util.Date();
java.sql.Date bidDate = new java.sql.Date(today.getTime());
/* public void setBidDate(Date bidDate)*/
newBid.setBidDate(bidDate);

Which is in a sense, the most paradox way of all, since in order to get the current date, you actually need to call getTime()!

References

More help about: using timestamps
http://download.oracle.com/javase/1.4.2/docs/api/java/text/SimpleDateFormat.html

Comments on Oracle XSQL, by M.Thomas

On the bright side, the text is well written, in American English, with a few spelling errors. It provides an introduction to PL/SQL, database design, Oracle Text for Oracle 9i, XML, including XSL, XPath and xsql, which is now considered obsolete(?). Its source code works and could be reused. On the dark side, the book is not an introductory level one, the chapters from the beginning to 14 are more reference like, until the true tutorial building of the web application begins. A javascript or java, introduction is missing, and the paragraphs about XPath are difficult to understand.
All in all, the book can be well used as a reference, provided that several corrections need to be made by the reader, in both its source code and text.

Monday, 12 July 2010

JDeveloper 11g:Using Log4j in EJB projects

Apart from the usual web client interface, a EJB 3 application can be accessed also by a plain Java Standard Edition client. This post clarifies the use of Log4j in the latter form of client. To add the Log4j jar library, double click the project, so that the window of the image appears. As for web based (view) client J2EE projects you can read it here:

All that 's written there is still valid. I would like to add a couple of things. First, you need to create the log4j.properties file in the following path:
C:\...\Model\src\
A copy of the log4j.properties file is given here for your convenience:
# **Set root logger level to DEBUG and its only appender to A.
log4j.rootLogger=DEBUG, A
# ***** A is set to be a ConsoleAppender.
log4j.appender.A=org.apache.log4j.ConsoleAppender
# ***** A uses PatternLayout.
log4j.appender.A.layout=org.apache.log4j.PatternLayout
log4j.appender.A.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

Secondly, when it comes to EJB model projects, you need to add the following code in italics, in order to avoid the expensive use of System.out.println() in your client classes:
...
import org.apache.log4j.Logger;


public class PlaceOrderClient {
static Logger logger =Logger.getLogger("PlaceOrderClient");
/* instead of Logger logger = Logger.getLogger(this.getClass().getSimpleName());*/
public static void main(String [] args) {
try {
final Context context = getInitialContext();
PlaceOrder placeOrder = (PlaceOrder)context.lookup("ejb3inaction-Model-PlaceOrder#actionbazaar.buslogic.PlaceOrder");
if (logger.isDebugEnabled())
             logger.debug("Exercising PlaceOrder EJB...");
// System.out.println("Exercising PlaceOrder EJB...");

The full source code is available on OTN:

http://www.oracle.com/technetwork/indexes/samplecode/jdeveloper-adf-sample-522118.html 
and is given without any guarantee of support whatsoever.
 
Finally, in case you prefer working with Eclipse, the process is quite similar. See for example:
http://snippets.dzone.com/posts/show/3248
If you need more tips about appenders:
http://www.mobilefish.com/developer/log4j/log4j_quickguide_appenders.html

Saturday, 10 July 2010

Comments on CompTIA Project + Study Guide

On the bright side, the book is very well written (American English) and organized with only a hand full of misspelling errors. The text is easy to follow most of the times, is full of real life examples, case studies and questions. The book does much more than just prepare you fully for the exam. It gives useful advice on daily problems. Its preliminary assessment test is a standard procedure for all Sybex books, to guide the reader to the chapters covering the knowledge he is missing.
On the dark side, the schedule development techniques and the performance reporting tools paragraphs are rather complicated and difficult to understand. Moreover, the book is heavily text based with very few diagrams and graphs.
All in all, the book provides you with all you need to pass the exams. In addition, it can be used as a reference resource throughout your professional career.

Friday, 9 July 2010

Comments on PeopleSoft Developer's Guide for PeopleTools & PeopleCode, by Judi Doolittle

On the bright side, the text is mostly well written, having some spelling errors. It serves well as an introduction to the application suite offered by Oracle and Peoplesoft. The first part is very descriptive, full of screen shots, and delves into architecture details. There is also a very useful appendix for learning PL/SQL, and some COBOL .
On the dark side, the second part is only good for leisure reading, not for learning how to code. There are only two chapters of merely showing the structure of Peoplecode, without any tutorial, or exercises. Themes such as combining it with Crystal reports are missing. Its source code is not available, you have to type it! You can read more acid criticism by a more experienced reader at:
http://www.amazon.com/review/R15036IT6F1BI2/ref=cm_cr_pr_viewpnt#R15036IT6F1BI2
All in all, the book serves only as an introduction, you cannot use it to actually learn how to write code.

Comments on Object-Oriented Systems Analysis and Design, 2nd edition, by S.Bennet et al

On the bright side, the book is very well written, without spelling errors by academic stuff mainly, in British English.
The text is easy to understand and to follow most of the times, thanks to the examples of a couple of case studies provided.
The book is full with helpful diagrams, graphs, flowcharts, questions, exercises etc, to help the reader make a quick progress. It is not technology biased towards any I.D.E., or framework, presenting both Sun/Oracle and Microsoft alternatives. Its indexes are valuable as a reference to the professional as well.
On the dark side, one could use more solutions to the exercises and answer pointers appendix instead of having to pay more for them(as of 2nd edition!). More use cases would be welcome as well!
All in all, the book is a success, a best seller,as of now at its fourth edition, valuable both as an introduction to the student and the professional as a reference.

Thursday, 1 July 2010

Comments on Beginning JavaServer Pages, by Chopra, Jones Li, Bell

On the bright side, the text is quite well written, with only a handful of misspellings for a 1252 pages huge book, as presented at its errata page linked here:
http://www.wrox.com/WileyCDA/WroxTitle/Beginning-JavaServer-Pages.productCd-076457485X,descCd-ERRATA.html
The source code of the book is complete, working (with the exception of the Struts chapter 19) and mostly reusable. The tutorial form of the text makes it easy to follow, so that you can practice further on your own, working on open source tools and frameworks, such as Apache ant, JUnit, JMeter, Hibernate, Tiles and the Tomcat web container.
On the dark side, the book does not delve into Servlets theory, nor does any use of any open source integrated development environment.
All in all, the book serves well the novice to intermediate reader, both as an introductory text at first and as a reference book in a later stage.