[+/-] : How to GBK(GB2312) and UTF-8 encoding conversion between in JavaScript

following js code show to how to convert text between Simplified Chinese GB 2312 text strings into UTF8 using JavaScript.

GB2312UTF8  = {
  Dig2Dec : function(s){
      var retV = 0;
      if(s.length == 4){
          for(var i = 0; i < 4; i ++){
              retV += eval(s.charAt(i)) * Math.pow(2, 3 - i);
          }
          return retV;
      }
      return -1;
  } ,

  Hex2Utf8 : function(s){
     var retS = "";
     var tempS = "";
     var ss = "";
     if(s.length == 16){
         tempS = "1110" + s.substring(0, 4);
         tempS += "10" +  s.substring(4, 10);
         tempS += "10" + s.substring(10,16);
         var sss = "0123456789ABCDEF";
         for(var i = 0; i < 3; i ++){
            retS += "%";
            ss = tempS.substring(i * 8, (eval(i)+1)*8);
            retS += sss.charAt(this.Dig2Dec(ss.substring(0,4)));
            retS += sss.charAt(this.Dig2Dec(ss.substring(4,8)));
         }
         return retS;
     }
     return "";
  } ,

  Dec2Dig : function(n1){
      var s = "";
      var n2 = 0;
      for(var i = 0; i < 4; i++){
         n2 = Math.pow(2,3 - i);
         if(n1 >= n2){
            s += '1';
            n1 = n1 - n2;
          }
         else
          s += '0';
      }
      return s;
  },

  Str2Hex : function(s){
      var c = "";
      var n;
      var ss = "0123456789ABCDEF";
      var digS = "";
      for(var i = 0; i < s.length; i ++){
         c = s.charAt(i);
         n = ss.indexOf(c);
         digS += this.Dec2Dig(eval(n));
      }
      return digS;
  },

  GB2312ToUTF8 : function(s1){
    var s = escape(s1);
    var sa = s.split("%");
    var retV ="";
    if(sa[0] != ""){
      retV = sa[0];
    }
    for(var i = 1; i < sa.length; i ++){
      if(sa[i].substring(0,1) == "u"){
        //alert(this.Str2Hex(sa[i].substring(1,5)));
        retV += this.Hex2Utf8(this.Str2Hex(sa[i].substring(1,5)));
  if(sa[i].length){
    retV += sa[i].substring(5);
  }
      }
      else{
     retV += unescape("%" + sa[i]);
  if(sa[i].length){
    retV += sa[i].substring(5);
  }
   }
    }
    return retV;
  },

  UTF8ToGB2312 : function(str1){
        var substr = "";
        var a = "";
        var b = "";
        var c = "";
        var i = -1;
        i = str1.indexOf("%");
        if(i==-1){
          return str1;
        }
        while(i!= -1){
    if(i<3){
                substr = substr + str1.substr(0,i-1);
                str1 = str1.substr(i+1,str1.length-i);
                a = str1.substr(0,2);
                str1 = str1.substr(2,str1.length - 2);
                if(parseInt("0x" + a) & 0x80 == 0){
                  substr = substr + String.fromCharCode(parseInt("0x" + a));
                }
                else if(parseInt("0x" + a) & 0xE0 == 0xC0){ //two byte
                        b = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        var widechar = (parseInt("0x" + a) & 0x1F) << 6;
                        widechar = widechar | (parseInt("0x" + b) & 0x3F);
                        substr = substr + String.fromCharCode(widechar);
                }
                else{
                        b = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        c = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        var widechar = (parseInt("0x" + a) & 0x0F) << 12;
                        widechar = widechar | ((parseInt("0x" + b) & 0x3F) << 6);
                        widechar = widechar | (parseInt("0x" + c) & 0x3F);
                        substr = substr + String.fromCharCode(widechar);
                }
     }
     else {
      substr = substr + str1.substring(0,i);
      str1= str1.substring(i);
     }
              i = str1.indexOf("%");
        }

        return substr+str1;
  }
};

test:
  GBK => UTF8:
  var utf8 = GB2312UTF8.GB2312ToUTF8("中文GB2312");

  UTF8 => GBK:
  GB2312UTF8.UTF8ToGB2312(utf8);

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[+/-] : How to send messages using PHP

sendMsg is a class which allows you to send a message to a contact from a specified account. It logs in, changes status to online, creates a new IM session with the target user, sends the message and ends both connections.

The Messenger server imposes a limit on how many IM sessions can be created per minute, so the script is not suited for sending messages to large numbers of contacts within the same login session (see below).

The user sending the message must be on the allow list of the receiving user; or, the target user must have “All others” on their allow list (as in the Windows Live Messenger options dialog). To get the login ticket for authentication it uses the MSNPAuth class, which is included in the ZIP file.

Because of the way the protocol works, the sending user doesn’t appear to come online because it does not synchronize lists.

This class has not been extensively tested, if you find a bug or error, please post a comment here.
Using sendMsg
Standard sending precedure - logging in, creating an IM session and sending a message:

$sendMsg = new sendMsg();
$sendMsg->login('sender@hotmail.com','password');
$sendMsg->createSession('recipient@hotmail.com');
$sendMsg->sendMessage('message', 'Times New Roman', 'FF0000');

The last two arguments for sendMessage() which specify font options are optional. The receiving client’s default font will be displayed if they are not specified.
createSession() should only be called a maximum of 8 times in any 60 second period, due to limits imposed by the Messenger service. The script will throw an error if you try calling createSession a 9th time.
Once createSession() has been called, sendMessage() can be used to send any number of messages to that user, for example:

$sendMsg = new sendMsg();
$sendMsg->login('sender@hotmail.com','password');
$sendMsg->createSession('recipient@hotmail.com');
$sendMsg->sendMessage('this is the first message');
$sendMsg->sendMessage('this is the second message');
$sendMsg->sendMessage('this is the third message');

createSession() can be called for each user that requires a message to be sent to. To send two messages to two different users:

$sendMsg = new sendMsg();
$sendMsg->login('sender@hotmail.com','password');
$sendMsg->createSession('firstperson@hotmail.com');
$sendMsg->sendMessage('hello first person');
$sendMsg->createSession('secondperson@hotmail.com');
$sendMsg->sendMessage('hello second person);

There is also a function which simplifies the procedure of sending a message to a single user:

$sendMsg = new sendMsg();
$sendMsg->simpleSend('sender@hotmail.com','password', 'recipient@hotmail.com','message');

The result property can be used to see how it went, refer to the constant definitions at the top of sendMsg.php for textual meaning. For description of socket errors, you can check the property error.
You can give it a try at the sandbox. If you have troubles getting the script working with connections error, please refer to Troubleshooting phpListGrab (phpListGrab uses similar code).
From: http://www.fanatic.net.nz/2005/02/15/send-a-message-using-php/
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[+/-] : How to send SMS in J2ME

The sample code on how to send SMS through J2ME.

import java.io.IOException;

import javax.microedition.io.Connector;
import javax.wireless.messaging.MessageConnection;
import javax.wireless.messaging.TextMessage;

/** Sends an SMS message */
public class SMSender implements Runnable {
  private String smsReceiverPort;
  private String message;
  private String phoneNumber;

  public SMSender(String smsReceiverPort) {
    this.smsReceiverPort = smsReceiverPort;
  }

  public void run() {
    StringBuffer addr = new StringBuffer(20);
    addr.append("sms://+");
    if (phoneNumber.length() == 11)
      addr.append("86");//  china

    addr.append(phoneNumber);
    // String address = "sms://+8613641301055";
    String address = addr.toString();

    MessageConnection smsconn = null;
    try {
      // Open the message connection.
      smsconn = (MessageConnection) Connector.open(address);
      // Create the message.
      TextMessage txtmessage = (TextMessage) smsconn
          .newMessage(MessageConnection.TEXT_MESSAGE);
      txtmessage.setAddress(address);// !!
      txtmessage.setPayloadText(message);
      smsconn.send(txtmessage);
    } catch (Exception e) {
      e.printStackTrace();
    }

    if (smsconn != null) {
      try {
        smsconn.close();
      } catch (IOException ioe) {
        ioe.printStackTrace();
      }
    }
  }

  public void send(String message, String phoneNumber) {
    this.message = message;
    this.phoneNumber = phoneNumber;
    Thread t = new Thread(this);
    t.start();
  }

}

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[+/-] : Using the Comparable interface to compare and sort objects

This code example shows how to compare and sort objects by implementing the Comparable interface. The code consists of a class called Main and another class called Car.

The Main class creates a few instances of the Car class (which is the one that implements the Comparable interface) and them compare them and also sort them.

The Car class has three attributes, make, year and mileage. Only the mileage attribute is really of importance here since it's the attribute used for comparing.

When a class implements the Comparable interface it has to implement a method called compareTo(). In that method the code has to be written to decide if two objects match or if one is larger than the other.

In the example we return 1 if the current car object (the one we're calling compareTo() on) has a greater mileage value than the object passed in as parameter, -1 if it's the other way around and if they're equal 0 is returned.

The toString() method is overridden so a car object can be printed out in a readable way. Finally we create an array of cars and pass it to the sort() method of the Arrays class and then print out the sorted array.

import java.util.Arrays;

/**
 *
 * @author javadb.com
 */
public class Main {
    
    /**
     * Creates objects using the Car class which implements the Comparable
     * interface.
     * Compares and sorts the objects by mileage.
     */
    public void comparableExample() {
        
        //Creating the objects that implements the Comparable interface
        Car car1 = new Car("Toyota", 2006, 5000);
        Car car2 = new Car("BMW", 2007, 5000);
        Car car3 = new Car("Chrysler", 2007, 4000);
        
        //Comparing the objects by calling the compareTo method on one of them
        //passing another object as argument.
        System.out.println("Car 1 equals Car 2: " + car1.compareTo(car2));
        System.out.println("Car 1 equals Car 3: " + car1.compareTo(car3));
        System.out.println("Car 2 equals Car 3: " + car2.compareTo(car3));
        System.out.println();
        
        //To sort them we create an array which is passed to the Arrays.sort()
        //method.
        Car[] carArray = new Car[] {car1, car2, car3};
        Arrays.sort(carArray);
        
        //Print out the sorted array
        for (Car car : carArray)
            System.out.println(car.toString());
    }
    
    //The Car class used to compare and sort objects.
    class Car implements Comparable {
        
        private String make;
        private int year;
        private int mileage;
        
        public Car(String make, int year, int mileage) {
            
            this.make = make;
            this.year = year;
            this.mileage = mileage;
        }
        
        //Mandatory method when implementing the
        //Comparable interface. In this method we
        //compare the mileage of the two car objects.
        public int compareTo(Object obj) {
            
            if (obj instanceof Car) {
                
                Car car = (Car) obj;
                if (this.mileage > car.getMileage())
                    return 1;
                else if (this.mileage < car.getMileage())
                    return -1;
            }
            return 0;
        }
        
        public void setMake(String make) {
            this.make = make;
        }
        
        public void setYear(int year) {
            this.year = year;
        }
        
        public void setMileage(int mileage) {
            this.mileage = mileage;
        }
        
        public String getMake() {
            return make;
        }
        
        public int getYear() {
            return year;
        }
        
        public int getMileage() {
            return mileage;
        }
        
        public String toString() {
            
            StringBuffer buffer = new StringBuffer();
            buffer.append("Make: " + make + "\n");
            buffer.append("Year: " + year + "\n");
            buffer.append("Mileage: " + mileage + "\n");
            
            return buffer.toString();
        }
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().comparableExample();
    }
}

The output from the code example above is:

Car 1 equals Car 2: 0
Car 1 equals Car 3: 1
Car 2 equals Car 3: 1

Make: Chrysler
Year: 2007
Mileage: 4000

Make: Toyota
Year: 2006
Mileage: 5000

Make: BMW
Year: 2007
Mileage: 5000

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[+/-] : How to read floppy disk information in C++

Reads information from an inserted floppy disk. like clusters, sectors etc.

//Disk.cpp
//Reads floppy disk properties(Ensure floppy is avaiable in drive)
//Renjith Joseph
//Perumbavoor P.O, Ernakulam Dist. Kerala State, india
//E-mail: renjithmathewjoseph@hotmail.com
//All rights reserved.

#include<iostream.h>
#include<conio.h>
#include<dos.h>
void main(){
     clrscr();
     //Floppy Drive Properties
     struct fatinfo diskinfo;
     getfat(1, &diskinfo);
     cout<<"Floppy Disk Properties..--------------------------";
     cout<<"
 Sectors per cluster:"<<diskinfo.fi_sclus;  cout<<"
 Number of clusters:"<<diskinfo.fi_nclus;  cout<<"
 Bytes per sector:"<<diskinfo.fi_bysec;
   struct dfree free;
   long avail;
   getdfree(1,&free);
   avail =(long)free.df_avail*(long)free.df_bsec*(long)free.df_sclus;
   cout<<"
 Total bytes available:"<<avail<<" Bytes";
   cout<<"
 Bytes free:"<<(long)free.df_avail<<" Bytes";
   getfatd(&diskinfo);
   //Hard disk drive properties
   cout<<"

 Default Drive 
 Properties..
 --------------------------";
 cout<<"
 Sectors per cluster:"<<diskinfo.fi_sclus; cout<<"
 FAT ID byte:"<<(diskinfo.fi_fatid & 0xFF);cout<<"
 Number of clusters:"<<diskinfo.fi_nclus;cout<<"
 Bytes per sector:"<<diskinfo.fi_bysec; getch();
}

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[+/-] : An implementation of Stack datastructure in C++

#include <iostream>
#include <new>
#include <string>
#include <sstream>
using namespace std;

#if !defined __STACK_H
#define __STACK_H

namespace stk{
  class Stack{
    private:
      int *p;
      int top,length;

      string str()const;
    public:
      Stack();
      Stack(const int);
      Stack(const Stack&);
      ~Stack();

      void push(int);
      int pop();
      int get_length()const;
      bool is_empty()const;
      Stack operator=(const Stack&);
      friend ostream& operator<<(ostream&,Stack&);

      class StackException{
        private:
          string desc;
        public:
          StackException(string exp){ desc="Exception : "+exp; }
          string get_exp(){ return desc; }
      };
  };

  Stack::Stack(){
    top=-1;
    length=0;
    p=0;
  }

  Stack::Stack(const int size){
    top=-1;
    length=size;
    try{
      p=new int[length];
    }catch(bad_alloc ba){
      cout<<"Memory can not be alllocated";
      return;
    }
  }

  Stack::Stack(const Stack &o){
    top=o.top;
    length=o.length;
    try{
      p=new int[length];
    }catch(bad_alloc ba){
      cout<<"Memory allocation failed";
      return;
    }
    for(int i=0;i<length;i++)
      p[i]=o.p[i];
  }

  Stack::~Stack(){
    if(p!=0)
      delete [] p;
  }

  void Stack::push(int elem){
    if(p==0){
      try{
        p=new int[1];
      }catch(bad_alloc ba){
        throw StackException("Memory fault");
      }
      length++;
      top++;
      p[top]=elem;
    }
    else if(top==(length-1)){
      int *q;
      try{
        q=new int[length+1];
      }catch(bad_alloc ba1){
        throw StackException("Memory fault");
      }
      for(int i=0;i<length;i++)
        q[i]=p[i];
      length++;
      top++;
      q[top]=elem;
      delete [] p;
      p=q;
    }
    else{
      top++;
      p[top]=elem;
    }
  }

  int Stack::pop(){
    if(p==0 || top==-1){
      throw StackException("Stack empty!");
    }
    int ret=p[top];
    top--;
    length--;

    if(top==-1){
      delete [] p;
      p=0;
    }
    else{
      int *q;
      try{
        q=new int[length];
      }catch(bad_alloc ba){
        throw StackException("Memory fault");
      }
      for(int i=0;i<length;i++)
        q[i]=p[i];
      delete [] p;
      p=q;
    }

    return ret;
  }

  int Stack::get_length()const{
    return length;
  }

  bool Stack::is_empty()const{
    return ((p==0)? true : false);
  }

  string Stack::str()const{  // private member function
    stringstream ss;
    for(int i=0;i<length;i++){
      ss << p[i];
      if(i!=(length-1))
        ss << ", ";
    }
    //ss<<"";
    return ss.str();
  }

  Stack Stack::operator=(const Stack &stk){
    length=stk.length;
    top=stk.top;

    if(p!=0)
      delete [] p;
    try{
      p=new int[length];
    }catch(bad_alloc ba){
      throw StackException("Memory fault in copying!");
    }
    for(int i=0;i<length;i++)
      p[i]=stk.p[i];

    return *this;
  }

  ostream& operator<<(ostream &o,Stack &s){
    o<<s.str();
    return o;
  }

} // namespace stk;

#endif

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[+/-] : How to run external system commands in Java

Running a system command is relatively simple - once you've seen it done the first time. It involves the use of two Java classes, the Runtime class and the Process class. Basically, you use the exec() method of the Runtime class to run the command as a separate process. This returns a Process object for managing the subprocess. Then you use the getInputStream() and getErrorStream() methods of the Process object to read the normal output of the command, and the error output of the command. What you do with the output of the command executed is entirely up to you and the application you're creating.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

//demonstrate  to check how many process are running.

public class RunCommand
{
  public static void main(String args[])
  {

    String s = null;

    try
    {

      // run the Unix "ps -ef" command
      // run "tasklist /svc" or "tasklist" command on windowns

      Process p = Runtime.getRuntime().exec("tasklist");
//      p.waitFor();

      BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));

      BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));

      // read the output from the command

      System.out.println("Here is the standard output of the command:\n");
      int count = 0;
      while ((s = stdInput.readLine()) != null)
      {
        System.out.println(s);
        count++;
      }
      System.out.println("total process:" + (count - 2));
      
      // read any errors from the attempted command

      System.out.println("Here is the standard error of the command (if any):\n");
      while ((s = stdError.readLine()) != null)
      {
        System.out.println(s);
      }

      System.exit(0);
    } catch (Exception e)
    {
      System.out.println("exception happened - here's what I know: ");
      e.printStackTrace();
      System.exit(-1);
    }
  }

}

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[+/-] : Multi-threaded programming - Multithreaded chat application in java

This is the server and the client program thatI wrote basically it gives u a good understanding of how sockets work in java .

/*This is the server for the MultiThreadedChatClient program thatI 
 wrote basically it gives u a good understanding of how sockets 
 work in java
 Author: Mohammed Alfaaz
 email:alfaaz@gmail.com
 */
import java.io.*;
import java.net.*;

public class MultiThreadChatServer
{

  // Declaration section:
  // declare a server socket and a client socket for the server
  // declare an input and an output stream

  static Socket clientSocket = null;
  static ServerSocket serverSocket = null;

  // This chat server can accept up to 10 clients' connections

  static clientThread t[] = new clientThread[10];

  public static void main(String args[])
  {

    // The default port

    int port_number = 8888;

    if (args.length < 1)
    {
      System.out.println("Usage: java MultiThreadChatServer " + 
          "Now using port number=" + port_number);
    } else
    {
      port_number = Integer.valueOf(args[0]).intValue();
    }

    // Initialization section:
    // Try to open a server socket on port port_number (default 8888)
    // Note that we can't choose a port less than 1023 if we are not
    // privileged users (root)

    try
    {
      serverSocket = new ServerSocket(port_number);
    }// try
    catch (IOException e)
    {
      System.out.println(e);
    }

    // Create a socket object from the ServerSocket to listen and accept
    // connections.
    // Open input and output streams for this socket will be created in
    // client's thread since every client is served by the server in
    // an individual thread

    // can use a for loop to control the number of clients
    // I have used the while so that we can have unlimited number of clients
    while (true)
    {
      try
      {
        clientSocket = serverSocket.accept();
        new clientThread(clientSocket, t).start();
        break;
      }// try

      catch (IOException e)
      {
        System.out.println(e);
      }
    }
  }
} // class

// This client thread opens the input and the output streams for a
// particular client, ask the client's name, informs all the clients
// currently connected to the server about the fact that a new client
// has joined the chat room, and as long as it receive data,
// echos that data back to all other clients.
// When the client leaves the chat room this thread informs also all
// the clients about that and terminates.

class clientThread extends Thread
{

  DataInputStream is = null;
  PrintStream os = null;
  Socket clientSocket = null;
  clientThread t[];

  public clientThread(Socket clientSocket, clientThread[] t)
  {
    this.clientSocket = clientSocket;
    this.t = t;
  }

  public void run()
  {
    String line;
    String name;
    try
    {
      is = new DataInputStream(clientSocket.getInputStream());
      os = new PrintStream(clientSocket.getOutputStream());
      os.println("Enter your name.");
      name = is.readLine(); // Recommends BufferedReader.readLine() method.
      os.println("Hello " + name + " to our chat room.To leave enter /quit in a new line");
      for (int i = 0; i <= 9; i++)
        if (t[i] != null && t[i] != this)
          t[i].os.println("*** A new user " + name + " entered the chat room !!!***");
      while (true)
      {
        line = is.readLine();
        if (line.startsWith("/quit"))
          break;
        for (int i = 0; i <= 9; i++)
          if (t[i] != null)
            t[i].os.println("<" + name + "> " + line);
      }
      for (int i = 0; i <= 9; i++)
        if (t[i] != null && t[i] != this)
          t[i].os.println("*** The user " + name + " is leaving the chat room !!!***");

      os.println("*** Bye " + name + " ***");

      // Clean up:
      // Set to null the current thread variable such that other client
      // could be accepted by the server

      for (int i = 0; i <= 9; i++)
        if (t[i] == this)
          t[i] = null;

      // close the output stream
      // close the input stream
      // close the socket

      is.close();
      os.close();
      clientSocket.close();
    } catch (IOException e)
    {
    };
  }
}

/*This is the client for the MultiThreadedChatServer program thatI 
 wrote basically it gives u a good understanding of how sockets 
 work in java
 Author: Mohammed Alfaaz
 email:alfaaz@gmail.com
 */

import java.io.*;
import java.net.*;

public class MultiThreadChatClient implements Runnable
{

  // Declaration section
  // clientClient: the client socket
  // os: the output stream
  // is: the input stream

  static Socket clientSocket = null;
  static PrintStream os = null;
  static DataInputStream is = null;
  static BufferedReader inputLine = null;
  static boolean closed = false;

  public static void main(String[] args)
  {

    // The default port

    int port_number = 8888;
    String host = "localhost";

    if (args.length < 2)
    {
      System.out.println("Usage: java MultiThreadChatClient " + 
          "Now using host=" + host + ", port_number="
          + port_number);
    } else
    {
      host = args[0];
      port_number = Integer.valueOf(args[1]).intValue();
    }
    // Initialization section:
    // Try to open a socket on a given host and port
    // Try to open input and output streams
    try
    {
      clientSocket = new Socket(host, port_number);
      inputLine = new BufferedReader(new InputStreamReader(System.in));
      os = new PrintStream(clientSocket.getOutputStream());
      is = new DataInputStream(clientSocket.getInputStream());
    } catch (UnknownHostException e)
    {
      System.err.println("Don't know about host " + host);
    } catch (IOException e)
    {
      System.err.println("Couldn't get I/O for the connection to the host " + host);
    }

    // If everything has been initialized then we want to write some data
    // to the socket we have opened a connection to on port port_number

    if (clientSocket != null && os != null && is != null)
    {
      try
      {

        // Create a thread to read from the server

        new Thread(new MultiThreadChatClient()).start();

        while (!closed)
        {
          os.println(inputLine.readLine());
        }

        // Clean up:
        // close the output stream
        // close the input stream
        // close the socket

        os.close();
        is.close();
        clientSocket.close();
      } catch (IOException e)
      {
        System.err.println("IOException:  " + e);
      }
    }
  }

  public void run()
  {
    String responseLine;

    // Keep on reading from the socket till we receive the "Bye" from the
    // server,once we received that then we want to break.
    try
    {
      while ((responseLine = is.readLine()) != null)
      {
        System.out.println(responseLine);
        if (responseLine.indexOf("*** Bye") != -1)
          break;
      }
      closed = true;
    } catch (IOException e)
    {
      System.err.println("IOException:  " + e);
    }
  }
}

...
Read more

[+/-] : How to add watermark to images in java

The tool to adding watermark to images,recommended markImage () methods to create watermark image. You can use it in jsp, servlet, app.

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGEncodeParam;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
  * The tool to adding watermark to images,recommended markImage () methods to create watermark image.
  *
  *
  */
public class ImageWatermark
{
  private static final int OFFSET_X = 10;
  private static final int OFFSET_Y = 10;

  public static final int MARK_LEFT_TOP = 1;
  public static final int MARK_RIGHT_TOP = 2;
  public static final int MARK_CENTER = 3;
  public static final int MARK_LEFT_BOTTOM = 4;
  public static final int MARK_RIGHT_BOTTOM = 5;


  /**
   * add a text to an image. as a single color, the effect is rather poor.
   * @param srcImg
   * @param text
   * @param font
   * @param color
   * @param offset_x
   * @param offset_y
   */
  public static void markText(String srcImg,String text, Font font, Color color, int offset_x, int offset_y)
  {
    try
    {
      File _file = new File(srcImg);
      Image src = ImageIO.read(_file);
      int width = src.getWidth(null);
      int height = src.getHeight(null);
      BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
      Graphics g = image.createGraphics();
      g.drawImage(src, 0, 0, width, height, null);
//    g.setBackground(Color.white);
      g.setColor(color);
      g.setFont(font);

      g.drawString(text,  offset_x, height - font.getSize() / 2 - offset_y);
      g.dispose();

      FileOutputStream out = new FileOutputStream(srcImg);
      JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
      encoder.encode(image);
      out.close();
    } catch (Exception e)
    {
      e.printStackTrace();
    }
  }


  /**
   * A logo picture to picture and watermark, effective this way
   * one instance : http://www.mvgod.com/images/poster/NaNiYaChuanQi2XKaiSiBinWangZi-10285-12811-19978-13383/3.jpg
   * @param srcImg --
   *          source image
   * @param markImg --
   *          watermark logo image
   * @param alpha --
   *          alpha composite  0 - 1,　0 Full transparency, 1 Opaque
   * @param mark_position --
   *          Watermark position, the four corners and central respectively,
   *       and so constant that ImageWatermark.MARK_LEFT_TOP
   */
  public final static void markImage(String srcImg, String markImg, float alpha, int mark_position)
  {
    try
    {
      File _file = new File(srcImg);
      if(!_file.exists()) return;
      
      Image src = ImageIO.read(_file);
      int width = src.getWidth(null);
      int height = src.getHeight(null);
      BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
      Graphics2D g = image.createGraphics();
      g.drawImage(src, 0, 0, width, height, null);

      // watermark image file
      File markFile = new File(markImg);
      if(!markFile.exists()) return;
      
      Image mark_img = ImageIO.read(markFile);
      int mark_img_width = mark_img.getWidth(null);
      int mark_img_height = mark_img.getHeight(null);
      g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
      switch (mark_position)
      {
      case ImageWatermark.MARK_LEFT_TOP:
        g.drawImage(mark_img, OFFSET_X, OFFSET_Y, mark_img_width, mark_img_height, null);
        break;
      case ImageWatermark.MARK_LEFT_BOTTOM:
        g.drawImage(mark_img, OFFSET_X, (height - mark_img_height - OFFSET_Y), mark_img_width, mark_img_height, null);
        break;
      case ImageWatermark.MARK_CENTER:
        g.drawImage(mark_img, (width - mark_img_width - OFFSET_X) / 2, (height - mark_img_height - OFFSET_Y) / 2,
            mark_img_width, mark_img_height, null);
        break;
      case ImageWatermark.MARK_RIGHT_TOP:
        g.drawImage(mark_img, (width - mark_img_width - OFFSET_X), OFFSET_Y, mark_img_width, mark_img_height, null);
        break;
      case ImageWatermark.MARK_RIGHT_BOTTOM:
      default:
        g.drawImage(mark_img, (width - mark_img_width - OFFSET_X), (height - mark_img_height - OFFSET_Y),
            mark_img_width, mark_img_height, null);
      }

      g.dispose();
      FileOutputStream out = new FileOutputStream(srcImg);
      JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
      encoder.encode(image);
      out.close();
    } catch (Exception e)
    {
      e.printStackTrace();
    }
  }

  public static void markImage(String srcImg, String markImg, float alpha)
  {
    markImage(srcImg, markImg, alpha, ImageWatermark.MARK_RIGHT_BOTTOM);
  }

  public static void markImage( String srcImg, String markImg)
  {
    markImage(srcImg, markImg, 0.5f, ImageWatermark.MARK_RIGHT_BOTTOM);
  }

  public static void markImageRandomPos(String srcImg,String markImg,  float alpha)
  {
    int[] a =
    { ImageWatermark.MARK_LEFT_TOP, ImageWatermark.MARK_RIGHT_TOP, ImageWatermark.MARK_LEFT_TOP, ImageWatermark.MARK_LEFT_BOTTOM,
        ImageWatermark.MARK_RIGHT_BOTTOM, ImageWatermark.MARK_RIGHT_BOTTOM, ImageWatermark.MARK_CENTER };

    int i =  new Random().nextInt(a.length);
    markImage(srcImg, markImg, alpha, a[i]);
  }

  /**
   * Semi-transparent, random location imprint. 
   * With a slightly higher risk of lower right corner of the upper left corner, the central minimum risk.
   * @param srcImg
   * @param markImg
   */
  public static void markImageRandomPos(String srcImg,String markImg)
  {
    markImageRandomPos(srcImg, markImg, 0.5f);
  }
  
  public static void main(String[] args)
  {
   //test
    String src_path = "/home/mvgod/car.jpg";
    String markImg =  "/home/mvgod/logo.png"
    
    float alpha = 0.5f;

    String text = "MVGod.com";
    Font font =new Font("Arial", Font.BOLD, 30)
    ImageWatermark.markText(text, src_path, font, Color.gray, 5, 5);

    
    ImageWatermark.markImage( src_path, markImg, alpha, ImageWatermark.MARK_CENTER);
//    ImageWatermark.markImageRandomPos(src_path,markImg);
  }
}

...
Read more

[+/-] : How to access a database by ADO with JavaScript

I have not found any sample that shows database access with javaScript. Well, I created one. It is very simple since Javascript has the activeXObject that allow us to call an external object in the same way that vbscript uses CreateObject.

//**************************************
// Name: ADO With JavaScript
// Description:I have not found any sample that shows database access with javaScript. Well, I created one.
// It is very simple since Javascript has the activeXObject that allow us to call an external object
// in the same way that vbscript uses CreateObject.
// By: Marcio Coelho
//
//Assumes:You need SQL Server, a valid login, and know the name of a table and at least one column to test the sample.
//
//Side Effects:None
//This code is copyrighted and has limited warranties.
//Please see http://www.Planet-Source-Code.com/xq/ASP/txtCodeId.2804/lngWId.2/qx/vb/scripts/ShowCode.htm
//for details.
//**************************************

<SCRIPT LANGUAGE=javascript>
 var conn = new ActiveXObject("ADODB.Connection") ;
 var connectionstring = "Provider=sqloledb; Data Source=itdev; Initial Catalog=pubs; User ID=sa;Password=yourpassword"
 conn.Open(connectionstring)
 var rs = new ActiveXObject("ADODB.Recordset")
 rs.Open("SELECT gif, description, page, location FROM menu1", conn)
// Be aware that I am selecting from this table, but you need to pick your own table
 while(!rs.eof)
  {
    alert(rs(0));
    rs.movenext
  }
   
   rs.close
  conn.close 
</SCRIPT>

...
Read more

[+/-] : Encrypts a string by the given "key"

A more slightly advanced encryption.Encrypts a string by the given "key".

import javax.swing.JOptionPane;


public class betterencryptor {

 public static void main(String[] args) {
  int key1 = Integer.parseInt(JOptionPane.showInputDialog("Input a key, a random large *prime* number:"));
  String message1 = JOptionPane.showInputDialog("Input a string to be encrypted/decrypted:");
  String crypt1 = cryptor(message1,key1);
  String decrypt1 = cryptor(crypt1,key1);
  System.out.println(crypt1);
  System.out.println(decrypt1);
 }


 public static String cryptor(String crypt,int key){
  byte[] string = crypt.getBytes();


  for(int k = 0;k < crypt.length();k++){
   string[k] = new Integer(string[k]^key%256).byteValue();
  }
  return (new String(string));
 }
}

...
Read more

[+/-] : How to create a zip file

This code example shows how to create a zip file. What we do is to create an input stream from the file we want to compress, and while we read from it we write the contents to an output stream. This output stream is of type ZipOutputStream which takes an FileOutputStream as parameter. Next we have to add a zip entry to the output stream before we start writing to it. We will also clean up by closing the zip entry and both the input stream and output stream when we are done.

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

public class Main {

    /**
     * Creates a zip file
     */
    public void createZipFile() {
        
        try {
            String inputFileName = "test.txt";
            String zipFileName = "compressed.zip";
            
            //Create input and output streams
            FileInputStream inStream = new FileInputStream(inputFileName);
            ZipOutputStream outStream = new ZipOutputStream(new FileOutputStream(zipFileName));
            
            // Add a zip entry to the output stream
            outStream.putNextEntry(new ZipEntry(inputFileName));
            
            byte[] buffer = new byte[1024];
            int bytesRead;
            
            //Each chunk of data read from the input stream 
            //is written to the output stream
            while ((bytesRead = inStream.read(buffer)) > 0) {
                outStream.write(buffer, 0, bytesRead);
            }

            //Close zip entry and file streams
            outStream.closeEntry();

            outStream.close();
            inStream.close();
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().createZipFile();
    }
    
}

...
Read more

[+/-] : Write to file using BufferedOutputStream

This code snippet shows how to write to a file using a BufferedOuputStream. Now it should be said that if you want to write text to a file you should probably find it easier to go with a Writer class like the BufferedWriter instead.
The write method of the BufferedOuputStream takes either a byte array or an int as argument so that is why we have to call getBytes() on any String that we provide to the write method. The getBytes method of the String class returns its content in the form of a byte array.
The other overloaded variant of the write method that takes an int as an argument prints the character that has the decimal value (or ascii value if you want) that matches the parameter. So in the example below we call write with 65 as the argument, which is the same as character 'A'.

Note that the construction of a BufferedOutputStream as below will overwrite any file with the same name that already exists.

import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class Main {
    
    /**
     * Prints some data to a file
     */
    public void writeToFile(String filename) {
        
        BufferedOutputStream bufferedOutput = null;
        
        try {
            
            //Construct the BufferedOutputStream object
            bufferedOutput = new BufferedOutputStream(new FileOutputStream(filename));
            
            //Start writing to the output stream
            bufferedOutput.write("Line one".getBytes());
            bufferedOutput.write("\n".getBytes()); //new line, you might want to use \r\n if you're on Windows
            bufferedOutput.write("Line two".getBytes());
            bufferedOutput.write("\n".getBytes());
            
            //prints the character that has the decimal value of 65
            bufferedOutput.write(65);
            
        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            //Close the BufferedOutputStream
            try {
                if (bufferedOutput != null) {
                    bufferedOutput.flush();
                    bufferedOutput.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().writeToFile("myFile.txt");
    }
}

If you run the code the contents of the file should look like this:

Line one
Line two
A
...
Read more

[+/-] : Read from file with BufferedInputStream

This example shows how to read the contents of a file using a BufferedInputStream. There are a couple of ways to do so, and in this example we use a byte array to store the data read. We loop through the file contents and fill out buffer up to the size of the buffer array until there are no more data left to read. It possible to read from the file one byte at a time, but to use a buffer is more efficient.

public class Main {
    
    /**
     * This method reads contents of a file and print it out
     */
    public void readFromFile(String filename) {
        
        BufferedInputStream bufferedInput = null;
        byte[] buffer = new byte[1024];
        
        try {
            
            //Construct the BufferedInputStream object
            bufferedInput = new BufferedInputStream(new FileInputStream(filename));
            
            int bytesRead = 0;
            
            //Keep reading from the file while there is any content
            //when the end of the stream has been reached, -1 is returned
            while ((bytesRead = bufferedInput.read(buffer)) != -1) {
                
                //Process the chunk of bytes read
                //in this case we just construct a String and print it out
                String chunk = new String(buffer, 0, bytesRead);
                System.out.print(chunk);
            }
            
        } catch (FileNotFoundException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        } finally {
            //Close the BufferedInputStream
            try {
                if (bufferedInput != null)
                    bufferedInput.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().readFromFile("myFile.txt");
    }
}

...
Read more

[+/-] : Read each line in a comma separated file into an array

In this example we read the lines of a comma separated file and split the values into an array. This is done fairly easy with the split() method, which takes a separator as an argument and returns an array of Strings.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileNotFoundException;
import java.io.IOException;


public class CsvTest {

  public void readFile() {

    BufferedReader br = null;
    
    try {
      
      br = new BufferedReader(new FileReader("thefile.csv"));
      String line = null;
      
      while ((line = br.readLine()) != null) {
        
        String[] values = line.split(",");
        
        //Do necessary work with the values, here we just print them out
        for (String str : values) {
          System.out.println(str);
        }
        System.out.println();
      }
    }
    catch (FileNotFoundException ex) {
      ex.printStackTrace();
    }
    catch (IOException ex) {
      ex.printStackTrace();
    }
    finally {
      try {
        if (br != null)
          br.close();
      }
      catch (IOException ex) {
        ex.printStackTrace();
      }
    }
  }

  public static void main(String[] args) {
    CsvTest test = new CsvTest();
    test.readFile();
  }
}

...
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[+/-] : Base64 encoding and Base64 decoding in C

#include "lib.h"

/**
 * characters used for Base64 encoding
 */  
const char *BASE64_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

/**
 * encode three bytes using base64 (RFC 3548)
 *
 * @param triple three bytes that should be encoded
 * @param result buffer of four characters where the result is stored
 */  
void _base64_encode_triple(unsigned char triple[3], char result[4])
 {
    int tripleValue, i;

    tripleValue = triple[0];
    tripleValue *= 256;
    tripleValue += triple[1];
    tripleValue *= 256;
    tripleValue += triple[2];

    for (i=0; i<4; i++)
    {
 result[3-i] = BASE64_CHARS[tripleValue%64];
 tripleValue /= 64;
    }
} 

/**
 * encode an array of bytes using Base64 (RFC 3548)
 *
 * @param source the source buffer
 * @param sourcelen the length of the source buffer
 * @param target the target buffer
 * @param targetlen the length of the target buffer
 * @return 1 on success, 0 otherwise
 */  
int base64_encode(unsigned char *source, size_t sourcelen, char *target, size_t targetlen)
 {
    /* check if the result will fit in the target buffer */
    if ((sourcelen+2)/3*4 > targetlen-1)
 return 0;

    /* encode all full triples */
    while (sourcelen >= 3)
    {
 _base64_encode_triple(source, target);
 sourcelen -= 3;
 source += 3;
 target += 4;
    }

    /* encode the last one or two characters */
    if (sourcelen > 0)
    {
 unsigned char temp[3];
 memset(temp, 0, sizeof(temp));
 memcpy(temp, source, sourcelen);
 _base64_encode_triple(temp, target);
 target[3] = '=';
 if (sourcelen == 1)
     target[2] = '=';

 target += 4;
    }

    /* terminate the string */
    target[0] = 0;

    return 1;
} 

/**
 * determine the value of a base64 encoding character
 *
 * @param base64char the character of which the value is searched
 * @return the value in case of success (0-63), -1 on failure
 */  
int _base64_char_value(char base64char)
 {
    if (base64char >= 'A' && base64char <= 'Z')
 return base64char-'A';
    if (base64char >= 'a' && base64char <= 'z')
 return base64char-'a'+26;
    if (base64char >= '0' && base64char <= '9')
 return base64char-'0'+2*26;
    if (base64char == '+')
 return 2*26+10;
    if (base64char == '/')
 return 2*26+11;
    return -1;
} 

/**
 * decode a 4 char base64 encoded byte triple
 *
 * @param quadruple the 4 characters that should be decoded
 * @param result the decoded data
 * @return lenth of the result (1, 2 or 3), 0 on failure
 */  
int _base64_decode_triple(char quadruple[4], unsigned char *result)
 {
    int i, triple_value, bytes_to_decode = 3, only_equals_yet = 1;
    int char_value[4];

    for (i=0; i<4; i++)
 char_value[i] = _base64_char_value(quadruple[i]);

    /* check if the characters are valid */
    for (i=3; i>=0; i--)
    {
 if (char_value[i]<0)
 {
     if (only_equals_yet && quadruple[i]=='=')
     {
  /* we will ignore this character anyway, make it something
   * that does not break our calculations */
  char_value[i]=0;
  bytes_to_decode--;
  continue;
     }
     return 0;
 }
 /* after we got a real character, no other '=' are allowed anymore */
 only_equals_yet = 0;
    }

    /* if we got "====" as input, bytes_to_decode is -1 */
    if (bytes_to_decode < 0)
 bytes_to_decode = 0;

    /* make one big value out of the partial values */
    triple_value = char_value[0];
    triple_value *= 64;
    triple_value += char_value[1];
    triple_value *= 64;
    triple_value += char_value[2];
    triple_value *= 64;
    triple_value += char_value[3];

    /* break the big value into bytes */
    for (i=bytes_to_decode; i<3; i++)
 triple_value /= 256;
    for (i=bytes_to_decode-1; i>=0; i--)
    {
 result[i] = triple_value%256;
 triple_value /= 256;
    }

    return bytes_to_decode;
} 

/**
 * decode base64 encoded data
 *
 * @param source the encoded data (zero terminated)
 * @param target pointer to the target buffer
 * @param targetlen length of the target buffer
 * @return length of converted data on success, -1 otherwise
 */  
size_t base64_decode(char *source, unsigned char *target, size_t targetlen)
 {
    char *src, *tmpptr;
    char quadruple[4], tmpresult[3];
    int i, tmplen = 3;
    size_t converted = 0;

    /* concatinate '===' to the source to handle unpadded base64 data */
    src = (char *)malloc(strlen(source)+5);
    if (src == NULL)
 return -1;
    strcpy(src, source);
    strcat(src, "====");
    tmpptr = src;

    /* convert as long as we get a full result */
    while (tmplen == 3)
    {
 /* get 4 characters to convert */
 for (i=0; i<4; i++)
 {
     /* skip invalid characters - we won't reach the end */
     while (*tmpptr != '=' && _base64_char_value(*tmpptr)<0)
  tmpptr++;

     quadruple[i] = *(tmpptr++);
 }

 /* convert the characters */
 tmplen = _base64_decode_triple(quadruple, tmpresult);

 /* check if the fit in the result buffer */
 if (targetlen < tmplen)
 {
     free(src);
     return -1;
 }

 /* put the partial result in the result buffer */
 memcpy(target, tmpresult, tmplen);
 target += tmplen;
 targetlen -= tmplen;
 converted += tmplen;
    }

    free(src);
    return converted;
} 

...
Read more

[+/-] : How to quickly sort Vector of objects that implement the Comparable interface in java

import java.util.Vector;  

/**
 * Implements the quicksort algorithm.
 * Sorts Vectors of objects that implement the Comparable interface.
 * The sort is based on Comparable.compare(obj) method.
 * @see Comparable
 */  
public class QuickSorter {

 /**
   * performs the sort.
   *
   * @param vect the Comparable Objects to be sorted.
   */  
  public static void sort(Vector vect)  {
    quickSort(vect, 0, vect.size()-1);
    insertionSort(vect);
  } 

  static void swap(Vector vect, int i, int j)  {
    Comparable x = (Comparable)vect.elementAt(i);
    vect.setElementAt(vect.elementAt(j), i);
    vect.setElementAt(x, j);
  } 

  static void quickSort(Vector vect, int el, int yu)  {
    if (yu-el < 16) {
      return;
    }
    int m, pivot, other;
    m = (yu+el)/2;
    if (((Comparable)vect.elementAt(el)).compare(vect.elementAt(yu)) < 0) {
      pivot = el;
      other = yu;
    }
    else {
      pivot = yu;
      other = el;
    }
    if (((Comparable)vect.elementAt(pivot)).compare(vect.elementAt(m)) < 0) {
      if (((Comparable)vect.elementAt(m)).compare(vect.elementAt(other)) < 0) {
        pivot = m;
      }
      else {
        pivot = other;
      }
    }

    swap(vect, el, pivot);

    int i, j;
    i = el + 1;
    j = yu - 1;
    while (true) {
      while (((Comparable)vect.elementAt(el)).compare(vect.elementAt(i)) < 0) {
        i++;
      }
      while (((Comparable)vect.elementAt(el)).compare(vect.elementAt(j)) > 0) {
        j--;
      }
      if (i >= j) {
        break;
      }
      swap(vect, i, j);
      i++;
      j--;
    }
    swap(vect, el, j);
    if (j - el < yu -i) {
      quickSort(vect, el, j-1);
      quickSort(vect, i, yu);
    }
    else {
      quickSort(vect, i, yu);
      quickSort(vect, el, j-1);
    }
  } 

  static void insertionSort(Vector vect)  {
    int i, j;
    for (i = 1; i < vect.size(); i++) {
      Comparable x = (Comparable)vect.elementAt(i);
      for (j = i;
          (j>0) && ((Comparable)vect.elementAt(j-1)).compare(x) > 0;
          j--) {
        vect.setElementAt(vect.elementAt(j-1), j);
      }
      vect.setElementAt(x, j);
    }
  } 

...
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[+/-] : Listing the system properties

By listing the properties of the system you run the program on you can find out a lot about it. Your program maybe should act in a certain way depending on what operating system it's currently on.
This code example shows how to retrieve the properties and how to enumerate through and print them out to the console.

import java.util.Enumeration;
import java.util.Properties;

/**
 *
 * @author javadb.com
 */
public class Main {
    
    /**
     * Lists the system properties
     */
    public void listSystemProperties() {
        
        Properties prop = System.getProperties();
        
        Enumeration enumeration = prop.keys();
        
        while (enumeration.hasMoreElements()) {
            String key = (String) enumeration.nextElement();
            System.out.println(key + " = " + prop.getProperty(key));
        }
        
    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().listSystemProperties();
    }
}

...
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[+/-] : Check if a String is a valid date

This example checks if a String is a valid date by parsing the String with an instance of the SimpleDateFormat class and returns true or false.

import java.text.SimpleDateFormat;
import java.text.ParseException;

public class DateTest {

  public boolean isValidDate(String inDate) {

    if (inDate == null)
      return false;

    //set the format to use as a constructor argument
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
    
    if (inDate.trim().length() != dateFormat.toPattern().length())
      return false;

    dateFormat.setLenient(false);
    
    try {
      //parse the inDate parameter
      dateFormat.parse(inDate.trim());
    }
    catch (ParseException pe) {
      return false;
    }
    return true;
  }

  public static void main(String[] args) {

    DateTest test = new DateTest();

    System.out.println(test.isValidDate("2004-02-29"));
    System.out.println(test.isValidDate("2005-02-29"));
  }
}

The output will be...
true
false

...since the year 2004 was a leap year....
Read more

[+/-] : how to determine window size in javascript

Use this snippet to determine the size of an open window. Can be used in many different situations, e.g., for setting the size of a div.

<script type="text/javascript">

if (window.innerWidth)
  theWidth=window.innerWidth;
else if (document.documentElement && document.documentElement.clientWidth)
  theWidth=document.documentElement.clientWidth;
else if (document.body)
  theWidth=document.body.clientWidth;

if (window.innerHeight)
  theHeight=window.innerHeight;
else if (document.documentElement && document.documentElement.clientHeight)
  theHeight=document.documentElement.clientHeight;
else if (document.body)
  theHeight=document.body.clientHeight;
//test
//alert(theWidth+'x'+theHeight);

</script>

...
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[+/-] : Getting data from the computer clipboard

Getting data from the system clipboard is implemented nicely in Java through the Toolkit class which has a getSystemClipboard method.
Since there isn't necessarily text contents in the clipboard the getSystemClipboard returns an instance of the class Transferable.
With that instance we have to test if the content is text before we do any processing with it. To test the code, just copy some text from the browser or some other document and have the java program print it out.

package com.javadb.example;

import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;

/**
 *
 * @author javadb.com
 */
public class Main {

    /**
     * Displays text from the clipboard
     */
    public void displayTextFromClipboard() {
        
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Clipboard clipboard = toolkit.getSystemClipboard();
        Transferable tran = null;
        
        try {
            
            //The parameter to getContents is not currently used so null should
            //be sent. If the clipboard is currently not available (for example 
            //it is used by another application) the method throws an
            //IllegalStateException.
            tran = clipboard.getContents(null);
            
        } catch (IllegalStateException ex) {
            System.out.println("The clipboard is unavailable.");
            return;
        }
        
        if (tran != null &&
                tran.isDataFlavorSupported(DataFlavor.stringFlavor)) {
            
            try {
                
                String clipboardContent =
                        (String)tran.getTransferData(DataFlavor.stringFlavor);
                
                System.out.println(clipboardContent);
                
            } catch (UnsupportedFlavorException ex) {
                ex.printStackTrace();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().displayTextFromClipboard();
    }
    
}

...
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[+/-] : Placing text on the computer clipboard

It is very easy to place text on the clipboard with Java.
We just get an instance of the default toolkit and from that we get hold of a reference to the clipboard object.
To place some text on the clipboard we need to pass an object of type Transferable and another object which is the clipboard owner to the method setContents.
To make it easy we may specify null as the owner, and as the first argument we pass an instance of the class StringSelection which implements the Transferable interface.
To test the code, just run it and then go to some text editor of your choice and select paste.

package com.javadb.example;

import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.StringSelection;

/**
 *
 * @author javadb.com
 */
public class Main {
    
    /**
     * Places text on the clipboard
     */
    public void placeTextOnClipboard() {
        
        //Get the toolkit
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        
        //Get the clipboard
        Clipboard clipboard = toolkit.getSystemClipboard();
        
        //The setContents method of the Clipboard instance takes a Transferable
        //as first parameter. The StringSelection class implements the Transferable
        //interface.
        StringSelection stringSel = new StringSelection("text to be placed on the clipboard");
        
        //We specify null as the clipboard owner
        clipboard.setContents(stringSel, null);

    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().placeTextOnClipboard();
    }
    
}

...
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[+/-] : Connect to a database and read from table

This example shows how to connect to a database, in this case a MS SQL Server database and read rows from a table.
It is assumed that the table has 3 columns and they all contains string-values (datatype char, varchar etc.).
To connect to another database type, just change the driver and url to match the specific type.

Note that you'll have to change some of the values to match your own environment(database, table, userid and password), and to make it work, you will have to download the jdbc driver from Microsoft and put it in your classpath.

import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Connection;

public class DBTest {

  Connection m_Connection = null;
  Statement m_Statement = null;
  ResultSet m_ResultSet = null;

  String m_Driver = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
  String m_Url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=MyDatabase";

  public DBTest() {

    //Load driver
    try {
      Class.forName(m_Driver);
    }
    catch (ClassNotFoundException ex) {
      ex.printStackTrace();
    }
  }

  public void doWork() {

    String query = "";

    try {
      //Create connection object
      m_Connection = DriverManager.getConnection(m_Url, "userid", "password");
      
      //Create Statement object
      m_Statement = m_Connection.createStatement();
      query = "SELECT * FROM MyTable";

      //Execute the query
      m_ResultSet = m_Statement.executeQuery(query);

      //Loop through the results
      while (m_ResultSet.next()) {

          System.out.print(m_ResultSet.getString(1));
          System.out.print(", ");
          System.out.print(m_ResultSet.getString(2));
          System.out.print(", ");
          System.out.print(m_ResultSet.getString(3));
          System.out.print("\n"); //new line
          
      }
   }
    catch (SQLException ex) {
      ex.printStackTrace();
      System.out.println(query);
    }
    finally {

      try {
        if (m_ResultSet != null)
          m_ResultSet.close();
        if (m_Statement != null)
          m_Statement.close();
        if (m_Connection != null)
          m_Connection.close();
      }
      catch (SQLException ex) {
        ex.printStackTrace();
      }
    }
  }

  public static void main(String[] args) {
    DBTest dbTest = new DBTest();
    dbTest.doWork();
  }
}
 

...
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[+/-] : How to extract contents of a zip file

This example shows how to extract a zipfile containing one file (or entry). The name of the zip file is 'compressed.zip' and we want to write the contents to a file called 'extracted.txt'.
We start by opening an input stream to the compressed file and an output stream to the file where we want the content to be extracted.
After that we get the next entry of the zip file (and the only entry in this case) - test so it's not null, and then start reading the contents from the input stream and writing each chunk read to the output stream.
As usual we should clean up properly afterwards so we close the input and output streams.

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

/**
 *
 * @author javadb.com
 */
public class Main {

    /**
     * Extracts a zip file
     */
    public void extractZipFile() {
        
        try {
            String zipFileName = "compressed.zip";
            String extractedFileName = "extracted.txt";
            
            //Create input and output streams
            ZipInputStream inStream = new ZipInputStream(new FileInputStream(zipFileName));
            OutputStream outStream = new FileOutputStream(extractedFileName);
            
            ZipEntry entry;
            byte[] buffer = new byte[1024];
            int nrBytesRead;
            
            //Get next zip entry and start reading data
            if ((entry = inStream.getNextEntry()) != null) {
                while ((nrBytesRead = inStream.read(buffer)) > 0) {
                    outStream.write(buffer, 0, nrBytesRead);
                }
            }
                    
            //Finish off by closing the streams
            outStream.close();
            inStream.close();
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().extractZipFile();
    }
    
}

...
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[+/-] : How to list the contents of a zip file

To list the contents of a zip file you need to get the entries of the file since every file in a zip file is represented by an entry. In this case we assume that the filename of the zip file is 'testfile.zip'. By calling the entries method of the ZipFile object we get an Enumeration back that can be used to loop through the entries of the file. Note that we have to cast each element in the Enumeration to a ZipEntry. Normally some more extensive processing of the entries would probably be done, but here we just print out the name of each entry (i.e the name of the file or directory in the zip file).

import java.io.IOException;
import java.util.Enumeration;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 *
 * @author javadb.com
 */
public class Main {
    
    public void listContentsOfZipFile() {
        
        try {
            ZipFile zipFile = new ZipFile("testfile.zip");
            
            Enumeration zipEntries = zipFile.entries();
            
            while (zipEntries.hasMoreElements()) {
                
                //Process the name, here we just print it out
                System.out.println(((ZipEntry)zipEntries.nextElement()).getName());
                
            }
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        new Main().listContentsOfZipFile();
        
    }
}

...
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[+/-] : How to remove duplicate items from an ArrayList

This code example shows how to remove duplicate items from an ArrayList.

  ArrayList arrayList1 = new ArrayList();
    
  arrayList1.add("A");
  arrayList1.add("A");
  arrayList1.add("B");
  arrayList1.add("B");
  arrayList1.add("B");
  arrayList1.add("C");
    
  //Create a HashSet which allows no duplicates
  HashSet hashSet = new HashSet(arrayList1);

  //Assign the HashSet to a new ArrayList
  ArrayList arrayList2 = new ArrayList(hashSet) ;
    
  //Ensure correct order, since HashSet doesn't
  Collections.sort(arrayList2);
    
  for (Object item : arrayList2)
    System.out.println(item);

Note that you will have to sort the ArrayList if you want to be sure that the items remain in correct order by calling the sort method of the Collection class. This will produce the following output:

A
B
C

...
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[+/-] : How to send a POST Request with Parameters From a Java Class

his example shows how to sent a POST request to a server with attached parameters. Two parameters are sent in the example code below, width and height. We use the URL and URLConnection classes to open the connection to the destination. Then the output stream is retrieved by calling getOutputStream() on the URLConnection object. With the output stream we can write the parameters and then start reading the response from the server using the input stream which we get by calling getInputStream() on the same URLConnection object. We assume there will only be character based content returned from the server so we use the BufferedWriter to read the response line by line.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
/**
 * Main.java
 *
 * @author www.javadb.com
 */
public class Main {
    
    /**
     * Extends the size of an array.
     */
    public void sendPostRequest() {
        
        //Build parameter string
        String data = "width=50&height=100";
        try {
            
            // Send the request
            URL url = new URL("http://www.somesite.com");
            URLConnection conn = url.openConnection();
            conn.setDoOutput(true);
            OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
            
            //write parameters
            writer.write(data);
            writer.flush();
            
            // Get the response
            StringBuffer answer = new StringBuffer();
            BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                answer.append(line);
            }
            writer.close();
            reader.close();
            
            //Output the response
            System.out.println(answer.toString());
            
        } catch (MalformedURLException ex) {
            ex.printStackTrace();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    /**
     * Starts the program
     *
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Main().sendPostRequest();
    }
}

...
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[+/-] : how to remove a line from a text file

This example shows how to delete a line from a file. The method removeLineFromFile takes two parameters, the first parameter is the file to remove from and the second parameter is the content of the line to remove. A tempfile is created and written to, except for the content that matches the second parameter. This way very large files can be handled without demanding so much internal memory. The original file is then deleted and the tempfile is renamed to the original filename. For example, the file test.txt is located in the current directory and contains three lines, and we will remove the second line "bbbbb".

aaaaa
bbbbb
ccccc

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.File;
import java.io.FileWriter;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;

public class FileUtil {


 public void removeLineFromFile(String file, String lineToRemove) {

   try {

     File inFile = new File(file);
    
     if (!inFile.isFile()) {
       System.out.println("Parameter is not an existing file");
       return;
     }
     
     //Construct the new file that will later be renamed to the original filename.
     File tempFile = new File(inFile.getAbsolutePath() + ".tmp");
    
     BufferedReader br = new BufferedReader(new FileReader(file));
     PrintWriter pw = new PrintWriter(new FileWriter(tempFile));
    
     String line = null;

     //Read from the original file and write to the new
     //unless content matches data to be removed.
     while ((line = br.readLine()) != null) {
      
       if (!line.trim().equals(lineToRemove)) {

         pw.println(line);
         pw.flush();
       }
     }
     pw.close();
     br.close();
    
     //Delete the original file
     if (!inFile.delete()) {
       System.out.println("Could not delete file");
       return;
     }
    
     //Rename the new file to the filename the original file had.
     if (!tempFile.renameTo(inFile))
       System.out.println("Could not rename file");
    
   }
   catch (FileNotFoundException ex) {
     ex.printStackTrace();
   }
   catch (IOException ex) {
     ex.printStackTrace();
   }
 }

 public static void main(String[] args) {
   FileUtil util = new FileUtil();
   util.removeLineFromFile("test.txt", "bbbbb");
 }
}

The file test.txt now looks like this:

aaaaa
ccccc

...
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