theLogicBlog

List<String> list = new ArrayList<String>();
list.add("one");
list.add("two");
list.add("three");
list.remove(1);
list.add("four");
list.add(0, "zero");
 
for (int i=0; i<list.size(); i++) {
	System.out.println(list.get(i));
}
 
Iterator<String> listItr = list.iterator();
while (listItr.hasNext()) {
	System.out.println(listItr.next());
}
 
// last element
list.get(list.size()-1);

HashSet<Integer> set = new HashSet<Integer>();
set.add(1);
set.add(2);
set.add(3);
set.add(2); // duplicate -> will be ignored
 
Iterator<Integer> setItr = set.iterator();
while (setItr.hasNext()) {
	System.out.println(setItr.next());
}
 
SortedSet<String> sortedSet = new TreeSet<String>();
sortedSet.add("Gamma");
sortedSet.add("Alpha");
sortedSet.add("Beta");
 
Iterator<String> sortedSetItr = sortedSet.iterator();
while (sortedSetItr.hasNext()) {
	System.out.println(sortedSetItr.next());
}

HashMap<String, String> map = new HashMap<String, String>();
map.put("stable", "Etch");
map.put("testing", "Lenny");
map.put("unstable", "Sid");
 
for (String key : map.keySet()) {
	System.out.println(key + " is " + map.get(key));
}
 
Iterator<String> mapItr = map.keySet().iterator();
while (mapItr.hasNext()) {
	String key = (String) mapItr.next();
	System.out.println(key + " is " + (String)map.get(key));
}
 
// Sorted Map
TreeMap<String, String> sortedMap = new TreeMap<String, String>();
sortedMap.put("8.04", "Hardy Heron");
sortedMap.put("7.10", "Gutsy Gibbon");
sortedMap.put("9.04", "Jaunty Jackalope");
sortedMap.put("8.10", "Intrepid Ibex");
 
Iterator<String> sortedMapItr = sortedMap.keySet().iterator();
while (sortedMapItr.hasNext()) {
	String key = (String) sortedMapItr.next();
	System.out.println(key + " xis " + (String)sortedMap.get(key));
}

<?xml version="1.0" encoding="UTF-8" ?>
<library>
  <book price="5.0">
  	<author>James Dean</author>
  	<type>Softcover</type>
  </book>
  <book price="8.0">
  	<author>Billy the Kid</author>
  	<type>Hardcover</type>
  </book>
  <book price="3.0">
  	<author>Tom Jones</author>
  	<type>Softcover</type>
  </book>
</library>

import java.io.File;
import java.util.Iterator;
import java.util.List;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
 
public class ReadXml {
 
  public static void main(String[] args) throws Exception {
 
    String filename = "library.xml";
    SAXBuilder builder = new SAXBuilder();
    Document doc = builder.build(new File(filename));
 
    // get root element
    Element root = doc.getRootElement();
 
    // get child elements
    List books = root.getChildren("book");
    System.out.println("This library has " + books.size() + " books:");
 
    Iterator i = books.iterator();
    while (i.hasNext()) {
      Element book = (Element) i.next();
      System.out.println(
        book.getChildText("author") + " (" + 
        book.getChildText("type") + ")" + ": " +
        book.getAttributeValue("price") + " €);
    }
  }
}

// start a transaction
start transaction update;
 
... MQL commands ...
 
// create savepoint
set transaction savepoint saveOne;
 
... MQL commands ...
 
// create savepoint
set transaction savepoint saveTwo;
 
// rollback until savepoint saveOne
abort transaction saveOne;
 
... MQL commands ...
 
// commit the MQL commands
commit transaction;
 
// abort (rollback) the MQL commands
abort transaction;

  private String mailSmtpServer = new String("mailserver.tld");
  private String mailFrom = new String("from@example.com");
  private String mailTo = new String("to@example.com");
  private String mailSubject = new String("Example Mail");
  private String mailText = new String("This is just an example.");
 
  Properties p = new Properties();
  p.put("mail.smtp.host", this.mailSmtpServer);
  Session s = Session.getDefaultInstance(p);
  while (true) {
    try {
      Message msg = new MimeMessage(s);
      msg.setFrom(new InternetAddress(this.mailFrom));
      msg.setRecipient(Message.RecipientType.TO, new InternetAddress(this.mailTo));
      msg.setRecipient(Message.RecipientType.CC, new InternetAddress(this.mailCc));
      msg.setSubject(this.mailSubject);
      msg.setContent(this.mailText, "text/plain");
      msg.setHeader("APPLICATION", "MccImporter");
      msg.setSentDate(new Date());
      Transport.send(msg);
      break;
    } catch (Exception e) {
      logger.error("Unable to send Mail to " + this.mailTo + " with subject " + this.mailSubject + " using server " + this.mailSmtpServer + ": " + e.getMessage());
      logger.error("New Try in 30 minutes");
      try {
        // wait 30 minutes until next try to send mail
        Thread.sleep(1000 * 60 * 30);
      } catch (InterruptedException el) { }
    }

import java.util.Random;
...
Random rand = new Random()
 
// random int between 1 and 6
int dice = rand.nextInt(5)+1
 
// random password generation
String values = "abcdefghijklmnopqrstuvwxyz" ;
values= values + values.toUpperCase() ;
values = values + "1234567890" ;
String password = "";
int j = 0;
while ( j<digits )
{
  password = password + choices.charAt( rand.nextInt( choices.length() ) );
  j = j + 1;
}