Other Pointers

• Weblogic Erroneous Handlers Error - this is caused by the jrockit version of jdk. To get the correct error message, use the Java jdk first. Source: http://ricksolutions.blogspot.hk/2009/03/fixing-erroneous-handlers-error.html
• checking tables on db2
select * from sysibm.systables where dbname='NACS01DB' and name like 'PC%'
• command for unzipping war files
jar xvf xxx.war
• Extracting the Contents a JAR File
  The basic command to use for extracting the contents of a JAR file is:
  

  jar xf jar-file [archived-file(s)] 

  Let's look at the options and arguments in this command:
  
  • The x option indicates that you want to extract files from the JAR archive.
  • The f options indicates that the JAR file from which files are to be extracted is specified on the command line, rather than through stdin.
  • The jar-file argument is the filename (or path and filename) of the JAR file from which to extract files.
  • archived-file(s) is an optional argument consisting of a space-delimited list of the files to be extracted from the archive. If this argument is not present, the Jar tool will extract all the files in the archive.
• character encoding - http://www.joelonsoftware.com/articles/Unicode.html
• DB2 Timestamp to java.util.Date or java.sql.Timestamp
  
  • DB2 format = yyyy-MM-dd HH:mm:ss.ZZZZZZ where Z = seconds since previos midnight (00000 - 86400), http://pic.dhe.ibm.com/infocenter/db2luw/v9r7/index.jsp?topic=%2Fcom.ibm.db2.luw.sql.ref.doc%2Fdoc%2Fr0007107.html
  • java.sql.Timestamp = yyyy-mm-dd hh:mm:ss.fffffffff where f = nanoseconds
  The ZZZZZZ part of DB2 timestamp is insignificant because it is just the total seconds since previos midnight.
  To convert to java.util.Date, use
  

  new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(dateStr)

  To convert to java.sql.Timestamp, use
  

  resultSet.getTimestamp([column name or column index])

• 
  

Ref:
http://technobuz.com/2011/04/run-commands-for-microsoft-applications/

Java Pointers / Links

• strength and limitations of for each loop (for( : ))
  http://today.java.net/article/2006/11/03/nuances-java-50-each-loop


• Loading properties/configurationfiles


• Java 5 New Features
  http://java.sun.com/j2se/1.5.0/docs/relnotes/features.html
  http://java.sun.com/developer/technicalArticles/releases/j2se15/
  http://download.oracle.com/javase/1.5.0/docs/guide/language/index.html


• Increase Java Performance
  http://java.sun.com/developer/technicalArticles/Programming/Performance/


• Java Language Best Practices
  http://docs.oracle.com/cd/A97688_16/generic.903/bp/java.htm


• Code Conventions for the Java Programming Language
  http://www.oracle.com/technetwork/java/codeconv-138413.html


• ThreadLocal - http://java.dzone.com/articles/java-thread-local-%E2%80%93-how-use


• String Concatenation
  - use plus operator(+) only if all operands are constants
  

      1) String temp = “alpha” + “beta”;
           '-> String temp = “alphabeta”; (compile time translation)
      2) String temp = x + “beta”;
           '-> String temp = (new StringBuilder()).append(x).append(“beta”).toString();

  - concat using plus operator uses StringBuilder and String behind the scenes:

      “alpha” + “beta” = new StringBuilder(String.toString(“alpha”)).append(“beta”).toString()

  - use String.concat if concatenating only 2 or few strings
  - use StringBuilder(unsynchronized)/StringBuffer(synchronized) for more than 2 strings, specially in a loop
  - in a loop, SB is better than concat is better than +
  - always initialize SB with initial capacity to greatly improve performance
  

  new SB() has 16 char initial capacity by default

  
  - best explanation is here: http://www.znetdevelopment.com/blogs/2009/04/06/java-string-concatenation/


• character set conversion

String stringToConvert = bmText;
byte[] convertStringToByte = stringToConvert.getBytes("UTF-8");
bmText = new String(convertStringToByte, "ISO-8859-1");
options.add(new SelectOption(bmValue, new String(bmText)));



• creating pdf
-header w/ image


  public void doHeader() throws Exception {
      Image logoImage = PDFUO.getLogoImage();
      //logoImage.setAbsolutePosition(ReportConstantsIF.ITEXT_POINTS/2, length - ReportConstantsIF.ITEXT_POINTS);
      logoImage.setAlignment(Image.ALIGN_TOP | Image.TEXTWRAP);
    
      Paragraph p = new Paragraph();
      p.add(logoImage);
      p.add(new Phrase("BEAR, STEARNS SECURITIES CORP." + "\n\n", new Font(Font.TIMES_ROMAN, 6, Font.BOLD)));
p.add(new Phrase(
        "ONE METROTECH CENTER NORTH" + "\n" +
  "BROOKLYN, NEW YORK 11201-3859" + "\n" +
  "(212) 272-1000", smallFont));
      p.setLeading(9f);
    
      HeaderFooter header = new HeaderFooter(p, false);
      header.setAlignment(Element.ALIGN_RIGHT);
      header.setBorder(PdfTable.NO_BORDER);

      document.setHeader(header);
  }


-error occurs and data is not displayed when the columns in a row is not complete in PdfPTable

JSP Pointers

• secure/nonsecure alerts on IE6 & 7
http://www.zorked.com/security/ie-mixed-content-secure-nonsecure-items/


• no caching on browsers
add: (remove space b/w < and META)

  
< META HTTP-EQUIV="Expires" CONTENT="0"> - any # less than 1 means no cache
< META HTTP-EQUIV="Pragma" CONTENT="no-cache"> - for backward compatability
< META HTTP-EQUIV="Cache-Control" CONTENT="no-cache"> - for HTTP 1.1 spec  



• day in Date

function fnGetPrevDayDate(objDate){
 // 1 day = 86400000 ms 
 // var datPrevDate = new Date(objDate.getTime() - 86400000);
 // code above returns incorrect result when time changes from DST to standard time
 
 var datPrevDate = new Date(objDate);
 datPrevDate.setDate(datPrevDate.getDate() - 1);
 return datPrevDate;
}



• html:checkbox
-If the form is in session and you change the checkbox from true(checked) to false(unchecked), the checkbox attribute in form is not set back to false. This is because the unchecked checkbox is not sent in the request and is therefore not set in the form.
-solution: Add a reset method in form & reset checkbox to false. Everytime you submit the form, form is reset and then populated before moving to action, thus having correct value for the checkbox.


• how to use indexId on logic:iterate

< logic:iterate id="entityRow" name="<%= DerivativeEntityConstantsIF.SEARCH_RESULT %>" scope="session" offset="<%= String.valueOf(offset)%>" length="<%= String.valueOf(maxLength)%>" indexId="indexNum">
  < html:select name="entityRow" property="linkageClassCode"
onchange='<%= "fnEditValue(this, " + indexNum + ")" %>' >...



• html element default values - defaultValue/defaultSelectedd

if (frm["termDeal.accountNo"].value != frm["termDeal.accountNo"].defaultValue) return true;
if (fnIsSelectChanged(frm["termDeal.currency"])) return true;

function fnIsSelectChanged(selectObj) {
  var index = selectObj.selectedIndex;
  var selectedOption = selectObj.options[index];
  if (selectedOption.defaultSelected) return false; 
  return true;
}



• use popUpCalendar.js

if (!document.layers){
var startDate = document.getElementById("personalInfoForm.dateOfBirth");
// use showCalendarWithHolidays if you want to show holidays
document.write("<[toRemove]a href='javascript:void(0)' onclick='showCalendarWithHolidays(this, startDate, \"mm-dd-yyyy\",null,1,-1,-1, true)'><[toRemove]img src='' border='0'/>");
}



• regex of replace

.value.replace(/_|-/g, '')  --> replace _ and - with empty str



• use of sessionScope

CL.isNewClient = ${sessionScope[ClientConstants.IS_NEW_CLIENT]} --> do not put semi colon at end (not sure if for AMS only)

Deep copy of Java objects

The class Object's clone method only performs a shallow copy. This means that it creates a new instance of the object but the fields of both the new and original object end up referencing the same objects because only the reference of the fields is copied to the new object. To make deep copies of an object, we can use this class:

import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;

/**
 * Utility for making deep copies (vs. clone()'s shallow copies) of
 * objects. Objects are first serialized and then deserialized. Error
 * checking is fairly minimal in this implementation. If an object is
 * encountered that cannot be serialized (or that references an object
 * that cannot be serialized) an error is printed to System.err and
 * null is returned. Depending on your specific application, it might
 * make more sense to have copy(...) re-throw the exception.
 *
 * A later version of this class includes some minor optimizations.
 */
public class ObjectCloner {

    // so that nobody can accidentally create an ObjectCloner object
    private ObjectCloner() {
    }

    /**
     * Returns a copy of the object, or null if the object cannot
     * be serialized.
     */
    public static Object deepCopy(Object orig) {
        Object obj = null;
        try {
            // Write the object out to a byte array
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream out = new ObjectOutputStream(bos);
            out.writeObject(orig);
            out.flush();
            out.close();

            // Make an input stream from the byte array and read
            // a copy of the object back in.
            ObjectInputStream in = new ObjectInputStream(
                new ByteArrayInputStream(bos.toByteArray()));
            obj = in.readObject();
        }
        catch(IOException e) {
            e.printStackTrace();
        }
        catch(ClassNotFoundException cnfe) {
            cnfe.printStackTrace();
        }
        return obj;
    }
}

Sample call: Object clone = ObjectCloner.deepCopy(oldObject);
A more optimized version can be found here: http://javatechniques.com/blog/faster-deep-copies-of-java-objects/

NYAOS (NYACUS,NYADOS,NYAOS-II)

- Nihongo Yet Another Open Shell
- an enhanced commandline shell for Windows,DOS,OS/2
- advantages include filename autocomplete, built-in color, history, etc.
- support and downloads: http://nyaos.org/


1) Download and unzip
2) create env.bat with:
set MAVEN_HOME=S:\commons\apache-maven-2.0.10
set ANT_HOME=S:\commons\apache-ant-1.7.0
set JAVA_HOME=R:\commons\bea\jrockit_150_15
set path=%JAVA_HOME%\bin\;%MAVEN_HOME%\bin;%ANT_HOME%\bin;%PATH%;S:\commons\scripts;D:\Program Files\Rational\clearcase\ClearCase\bin;s:\commons\firefox
mvn -version
3) use nyacus as your cmd with the env properties by creating mycmd.bat with:
nyacus -r env.bat (means that you are loading the script file env.bat instead of _nya)
4) can start other apps by creating start command like eclipse.bat:
set path=R:\commons\bea\jrockit_150_15\bin\;%PATH%;
cmd /C start R:\commons\eclipse -data R:\bel\workspace\workspace33 -vmargs -Xms40m -Xmx512m -XX:MaxPermSize=256m
5) launch mycmd.bat
6) start other apps by calling filename of .cmd