Wednesday, October 31, 2012

Print map of India using C

I don't know from where I got this code but its amazing ;)

#include <stdio.h> 
int main()
{
 int a,b,c;
 int count = 1;
 for (b=c=10;a="- FIGURE?, UMKC,XYZHello Folks,\
      TFy!QJu ROo TNn(ROo)SLq SLq ULo+\
      UHs UJq TNn*RPn/QPbEWS_JSWQAIJO^\
      NBELPeHBFHT}TnALVlBLOFAkHFOuFETp\
      HCStHAUFAgcEAelclcn^r^r\\tZvYxXy\
      T|S~Pn SPm SOn TNn ULo0ULo#ULo-W\
      Hq!WFs XDt!" [b+++21]; )

      for(; a-- > 64 ; )
       putchar ( ++c=='Z' ? c = c/ 9:33^b&1); return 0; 

 return 0;
}

The Output

                    !!!!!!                                                     
                    !!!!!!!!!!                                                 
                     !!!!!!!!!!!!!!!                                           
                       !!!!!!!!!!!!!!                                          
                     !!!!!!!!!!!!!!!                                           
                      !!!!!!!!!!!!                                             
                      !!!!!!!!!!!!                                             
                        !!!!!!!!!!!!                                           
                        !!!!!!!!                                               
                        !!!!!!!!!!                                             
                       !!!!!!!!!!!!!!                                          
                     !!!!!!!!!!!!!!!!                                          
                    !!!!!!!!!!!!!!!!                                  !!!!!    
                  !!!!!!!!!!!!!!!!!!!                               !!!!!!!!!! 
                 !!!!!!!!!!!!!!!!!!!!!!!                 !         !!!!!!!!!!  
            !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!              !!     !!!!!!!!!!!!    
           !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!      !!!!!!!!       
            !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      
             !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!       
              !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  !!!!!!!!!!!!       
       !!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!!!!!        
      !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!      !!!!!         
          !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !!!          
        !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!        !          
          !!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                       
           !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                         
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                          
                 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                           
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                               
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!                               
                  !!!!!!!!!!!!!!!!!!!!!!!!!!!!                                 
                  !!!!!!!!!!!!!!!!!!!!!!!!!!                                   
                  !!!!!!!!!!!!!!!!!!!!!!!!!                                    
                   !!!!!!!!!!!!!!!!!!!!!!!!                                    
                    !!!!!!!!!!!!!!!!!!!!                                       
                    !!!!!!!!!!!!!!!!!!!                                        
                     !!!!!!!!!!!!!!!!                                          
                      !!!!!!!!!!!!!!!!                                         
                      !!!!!!!!!!!!!!!                                          
                       !!!!!!!!!!!!!!                                          
                        !!!!!!!!!!!!                                           
                        !!!!!!!!!!!!                                           
                        !!!!!!!!!!!!                                           
                          !!!!!!!!                                             
                          !!!!!!                                               
                           !!!!                                                
   

Query system for an environment variable value using C/C++

Today one of my colleague asked me how to query an environment variable using C++. The solution is simple, just use getenv() method. See the below code.

#include <iostream>
#include <cstdlib>
#include <string>

using namespace std;
#pragma warning(disable: 4996) // disable warning for getenv()

int main()
{
 char *pointer = NULL;

 string str;
 cout<<"Enter the environment variable: ";

 while (cin>>str) {
  if(str.compare("exit") == 0) break;
  if(pointer = getenv(str.c_str())) {
   cout<<endl<<"Value of \""<<str<<"\" Variable: "<<pointer<<endl<<endl<<"Enter the environment variable: ";
  }else {
   cout<<"No such variables defined."<<endl<<"Enter the environment variable: ";
  }
 }
}

Tuesday, October 9, 2012

HttpServer - The Oracle JDK 1.6 Hidden Feature

I have seen this class many a times, but never encountered a scenario to use it. Recently in one of my application I needed to embedded a HTTP server. So I thought, Why not give this class a try !!

HTTP server infrastructure/framework is very simple to implement and is bundled only with the Oracle JDK 1.6. Following are the main classes:
  1. HttpServer
  2. HttpContext
  3. HttpExchange
See this link for sun.* package discussions.

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.URLDecoder;
import java.util.List;
import java.util.concurrent.Executors;

import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

public class JavaServer 
{
 public static final String nl = System.getProperty("line.separator");

 public static void main(String[] args) throws Exception 
 {
  if(args.length != 2)
  {
   printUsage();
   System.exit(-1);
  }
  String strPort = null;
  String strAddress = null;

  for (int i = 0; i < args.length; i++) 
  {
   if(args[i].startsWith("-p")){
    strPort = args[i].substring(2, args[i].length()).trim();
   }else if(args[i].startsWith("-a")){
    strAddress = args[i].substring(2, args[i].length()).trim();
   }else
    throw new IllegalArgumentException("Unknown command '" + args[i]+ "'");
  }

  if(strAddress.length() == 0 || strPort.length() == 0)
   throw new IllegalArgumentException("Port = " + strPort + ", IP = " + strAddress);

  int port = Integer.parseInt(strPort);
  InetSocketAddress address = new InetSocketAddress(strAddress, port);

  System.out.println("Going to run server on '" + address + "'");

  new JavaServer().start(address);
 }

 private static void printUsage() {
  System.out.println("$JavaServer -p<Port> -a<IP Address>");
 }

 private HttpServer server;

 public void start(InetSocketAddress address) throws IOException
 {
  server = HttpServer.create(address, 0); 
  server.setExecutor(Executors.newCachedThreadPool());
  server.createContext("/", new RootHandler());
  server.start();
 }
}

class RootHandler implements HttpHandler 
{
 private static final int BUFFER_SIZE = 1024;

 public void handle(HttpExchange exchange) throws IOException
 {
  String method = exchange.getRequestMethod();

  if(method.equalsIgnoreCase("get"))
  {
   String request = "";
   ByteArrayOutputStream baos = new ByteArrayOutputStream(BUFFER_SIZE);
   InputStream is = exchange.getRequestBody();

   byte[] buff = new byte[BUFFER_SIZE];
   while (true) 
   {
    int out = is.read(buff);
    if(out == -1)
     break;
    baos.write(buff, 0, out);
   }

   is.close();

   if (baos.size() > 0) {
    request = URLDecoder.decode(baos.toByteArray().toString(), "UTF-8");
   } else {
    request = null;
   }

   StringBuilder buf = new StringBuilder();
   buf.append("<html><head><title>Simple HTTP Server !!</title></head><body>");
   buf.append("<p><pre>");
   buf.append(exchange.getRequestMethod() + " " + exchange.getRequestURI() + " " + exchange.getProtocol() + JavaServer.nl);

   Headers headers = exchange.getRequestHeaders();

   for (String name : headers.keySet()) {
    List<String> values = headers.get(name);
    for (String value : values) {
     buf.append(name + " --> " + value + JavaServer.nl);
    }
   }
   if (request != null) {
    buf.append(JavaServer.nl);
    buf.append(request);
   }

   buf.append("</pre></p>");
   buf.append("</body></html>\n");

   String response = buf.toString();

   Headers responseHeaders = exchange.getResponseHeaders();
   responseHeaders.set("Content-Type", "text/html");
   exchange.sendResponseHeaders(HttpURLConnection.HTTP_OK, response.length());

   OutputStream res = exchange.getResponseBody();
   res.write(response.getBytes());
   res.close();
  }else
  {
   String response = "Bad request method !!";
   exchange.sendResponseHeaders(HttpURLConnection.HTTP_BAD_METHOD, response.length());
   OutputStream res = exchange.getResponseBody();
   res.write(response.getBytes());

   res.close();
  }
  exchange.close();
 }
}

Steps to run the above code

  1. Compile it using Oracle JDK 1.6
  2. Then execute this command on console (without quotes) 'Java JavaServer -p<port number> -a<ipaddress or localhost>' . For example, java JavaServer  -p5463 -a127.0.0.1
  3. Open your browser and type the URL. For example, http://127.0.0.1:5463/

You should see something like this (depends on the browser):


Monday, October 1, 2012

How to open a Java file in read-only mode?

In one of my eclipse plugin based application I wanted to open Java files in read only mode. One option was to use org.eclipse.jface.text.source.SourceViewer , where I could have used JavaSourceViewerConfiguration
for providing Java highlighting and all. But there were two problems:
  1. Source viewer won't inherit the Java editor settings (and if you have modified eclipse Java editor theme), which means your background and foreground in the SourceViewer gets completely messed up.
  2. Secondly you would lose all the markup and bookmarking facilities available with editors
So, I decided to extend the existing Java editor. The steps are extremely simple,
  1. Create an editor extension
  2. Extend the extension class with org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor
  3. Override some of the methods
  4. Open your file with this editor

Code

Editor Code

import org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor;

@SuppressWarnings("restriction")
public class ReadonlyEd extends CompilationUnitEditor 
{
 public static final String ID = "read.only";
 public ReadonlyEd() {
 }
 @Override
 public boolean isEditable() {
     return false;
 }
 @Override
 public boolean isEditorInputModifiable() {
     return false;
 }
 @Override
 public boolean isEditorInputReadOnly() {
     return true;
 }
 @Override
 public boolean isDirty() {
     return false;
 }
}

Code for Invoking the Editor

IFile file = ...; // Get the Java file instance
IWorkbenchPage page = ...; // Get the workbench page
  
FileEditorInput input = new FileEditorInput(file);
try {
 IDE.openEditor(window.getActivePage(), input, ReadonlyEd.ID);
} catch (PartInitException e) {
 e.printStackTrace();
}

Monday, September 24, 2012

How to hide a window from Win32 Taskbar?


Argh !!! I don't know why but I keep forgetting the ex-style bit for this... 
To prevent the window button from being placed on the taskbar, create the unowned window with the WS_EX_TOOLWINDOW extended style. As an alternative, you can create a hidden window and make this hidden window the owner of your visible window.
The Shell will remove a window's button from the taskbar only if the window's style supports visible taskbar buttons. If you want to dynamically change a window's style to one that doesn't support visible taskbar buttons, you must hide the window first (by calling ShowWindow with SW_HIDE), change the window style, and then show the window.
Taken from here: The Taskbar

Tuesday, September 18, 2012

3 easy steps to self-sign a Applet Jar file

Found this link that explains how to self-sign an applet in 3 easy steps:
  1. keytool -genkey -keystore myKeyStore -alias me
  2. keytool -selfcert -keystore myKeyStore -alias me
  3. jarsigner -keystore myKeyStore jarfile.jar me

Thursday, August 23, 2012

Firebug Lite for SWT Browser on Windows

Recently I came across this question on stackoverflow 'Eclipse swt browser and firebug lite'. The solution seemed very obvious. I answered the question there also, you can always upvote it ;).

The output:


The code for the same is as follows:

import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class FirebugLite 
{
 public static void main(String[] args) {
  new FirebugLite().start();
 }
 
 public void start()
 {
  Display display = new Display();
  Shell shell = new Shell(display);
  shell.setLayout(new GridLayout(1, false));
  GridData gridData = new GridData(SWT.FILL, SWT.FILL, true, true);
  gridData.widthHint = SWT.DEFAULT;
  gridData.heightHint = SWT.DEFAULT;
  shell.setLayoutData(gridData);
  shell.setText("Firebug Lite for SWT ;)");
  
  final Browser browser = new Browser(shell, SWT.NONE);
  GridData gridData2 = new GridData(SWT.FILL, SWT.FILL, true, true);
  gridData2.widthHint = SWT.DEFAULT;
  gridData2.heightHint = SWT.DEFAULT;
  browser.setLayoutData(gridData2);
  
  Button button = new Button(shell, SWT.PUSH);
  button.setLayoutData(new GridData(SWT.CENTER, SWT.CENTER, false, false));
  button.setText("Install");
  button.addSelectionListener(new SelectionAdapter() {
   public void widgetSelected(SelectionEvent e) {
    browser.setUrl("javascript:(function(F,i,r,e,b,u,g,L,I,T,E){if(F.getElementById(b))return;E=F[i+'NS']&&F.documentElement.namespaceURI;E=E?F[i+'NS'](E,'script'):F[i]('script');E[r]('id',b);E[r]('src',I+g+T);E[r](b,u);(F[e]('head')[0]||F[e]('body')[0]).appendChild(E);E=new%20Image;E[r]('src',I+L);})(document,'createElement','setAttribute','getElementsByTagName','FirebugLite','4','firebug-lite.js','releases/lite/latest/skin/xp/sprite.png','https://getfirebug.com/','#startOpened');");
   }
  });
  
  browser.setUrl("http://stackoverflow.com/questions/12003602/eclipse-swt-browser-and-firebug-lite");

  shell.open();
  while (!shell.isDisposed()) {
   if (!display.readAndDispatch())
    display.sleep();
  }
  display.dispose();
 }
}

Tuesday, July 31, 2012

SWT Browser and Image Capture

Recently I was playing with the SWT-COM bridge and its Win32 APIs. Believe me or not, but the SWT Browser is the best SWT based UI control I have seen (you can argue but without any success). 

One of the experimental feature I tried accomplishing was to print the full HTML page as Image, and the result was superb !!

See the below images for the embedded browser control and the output of the image capturing utility !! Cool right ;)

Modified Browser Control:




Captured Image:


Tuesday, June 5, 2012

Atlapp and secure atl !!

After upgrading to VS2008, I started getting errors for lstrlenA, size_t, and lstrcpynA. My "include directories" settings are exactly the same as my old VS2005, and if I open the project in VS2005, everything compiles just fine. So what is the fix for this problem??

And the fix is really simple, before including atlapp.h, just define:
 
#define _SECURE_ATL 1 


Tuesday, May 1, 2012

SWT - Capturing Control Screen-Shot

SWT code for capturing control screen-shot.

public class ScreenCaptureTest 
{
 public static void main(String[] args) 
 {
  String[] names  = {"Harry", "Sally", "Jhon", "Tim", "Scott"};
  String[] msg = {"Hello World!", "Today is a nice day to walk", "I am bored", "This is how you take widget capture", "Ha Ha Ha!! That's funny !"}; 
  
  final Display display = new Display();
  final Shell shell = new Shell(display);
  shell.setText("Screen Capture");
  shell.setLayout(new GridLayout(1, true));
  
  final Composite composite = new Composite(shell, SWT.BORDER);
  composite.setLayout(new GridLayout(2, true));
  composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
  
  Table table = new Table(composite, SWT.BORDER|SWT.V_SCROLL|SWT.H_SCROLL|SWT.FULL_SELECTION);
  
  table.setLinesVisible(true);
  table.setHeaderVisible(true);
  
  table.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
  
  TableColumn columnName = new TableColumn(table, SWT.LEFT);
  columnName.setText("Name");
  columnName.setWidth(100);
  
  TableColumn columnMsg = new TableColumn(table, SWT.LEFT);
  columnMsg.setText("Message");
  columnMsg.setWidth(200);
  
  for (int i = 0; i < 5; i++) 
  {
   TableItem item = new TableItem(table, SWT.NONE, 0);
   item.setText(0, names[i]);
   item.setText(1, msg[i]);   
  }
  
  StyledText text = new StyledText (composite, SWT.BORDER);
  text.setText("0123456789 ABCDEFGHIJKLM NOPQRSTUVWXYZ");
  text.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
  
  StyleRange style1 = new StyleRange();
  style1.start = 0;
  style1.length = 10;
  style1.fontStyle = SWT.BOLD;
  text.setStyleRange(style1);
  
  StyleRange style2 = new StyleRange();
  style2.start = 11;
  style2.length = 13;
  style2.foreground = display.getSystemColor(SWT.COLOR_RED);
  text.setStyleRange(style2);
  
  StyleRange style3 = new StyleRange();
  style3.start = 25;
  style3.length = 13;
  style3.background = display.getSystemColor(SWT.COLOR_BLUE);
  text.setStyleRange(style3);
  
  Button button = new Button(shell, SWT.PUSH);
  button.setText("Capture");
  button.pack();

  button.addListener(SWT.Selection, new Listener()
  {
   public void handleEvent(Event event) 
   {
    GC gc = new GC(display);
    final Image image = new Image(display, shell.getBounds());
    gc.copyArea(image, shell.getBounds().x, shell.getBounds().y);
    gc.dispose();

    Shell popup = new Shell(shell);
    popup.setText("Captured Image");
    popup.addListener(SWT.Close, new Listener() {
     public void handleEvent(Event e) {
      image.dispose();
     }
    });

    Canvas canvas = new Canvas(popup, SWT.NONE);
    canvas.setBounds(0,0,image.getImageData().width, image.getImageData().height);
    canvas.addPaintListener(new PaintListener() {
     public void paintControl(PaintEvent e) {
      e.gc.drawImage(image, 0, 0);
     }
    });
    popup.pack();
    popup.open();
   }
  });
  
  shell.pack();
  shell.open();
  
  while (!shell.isDisposed()) {
   if (!display.readAndDispatch())
    display.sleep();
  }
  
  display.dispose();
 }
}

Original Composite:


Captured Image:

Wednesday, April 18, 2012

Programmatically create eclipse Java project

Following is a brief code snippet for creating an eclipse Java project using core JDT API.

private IJavaProject createProject() throws Exception
{
    IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
    String projName = getProjectName();

    if(projName == null || projName.trim().length() == 0)
        return null;

    //create eclipse project
    IProject project = root.getProject(projName);
    if(project.exists())
        project.delete(true, null);

    project.create(null);
    project.open(null);

    //set the java project nature
    IProjectDescription description = project.getDescription();
    description.setNatureIds(new String[] { JavaCore.NATURE_ID});
    project.setDescription(description, null);

    //create java project
    IJavaProject javaProject = JavaCore.create(project);

    //add bin/ouput folder
    IFolder binFolder = project.getFolder("bin");
    binFolder.create(false, true, null);
    javaProject.setOutputLocation(binFolder.getFullPath(), null);

    //add libs to project class path
    List<IClasspathEntry> entries = new ArrayList<IClasspathEntry>();
    IVMInstall vmInstall = JavaRuntime.getDefaultVMInstall();
    LibraryLocation[] locations = JavaRuntime.getLibraryLocations(vmInstall);
    for (LibraryLocation element : locations) {
        entries.add(JavaCore.newLibraryEntry(element.getSystemLibraryPath(), null, null));
    }
    
    javaProject.setRawClasspath(entries.toArray(new IClasspathEntry[entries.size()]), null);

    //create source folder
    IFolder sourceFolder = project.getFolder("src");
    sourceFolder.create(false, true, null);

    IPackageFragmentRoot srcRoot = project.getPackageFragmentRoot(sourceFolder);
    IClasspathEntry[] oldEntries = project.getRawClasspath();
    IClasspathEntry[] newEntries = new IClasspathEntry[oldEntries.length + 1];
    System.arraycopy(oldEntries, 0, newEntries, 0, oldEntries.length);
    newEntries[oldEntries.length] = JavaCore.newSourceEntry(srcRoot.getPath());
    project.setRawClasspath(newEntries, null);

    return javaProject;
}

private String getProjectName()
{
    String init_value = "project_" + System.currentTimeMillis();
    InputDialog dialog = new InputDialog(getShell(), "Java Project", "Provide project name ..", init_value, new IInputValidator() {
        public String isValid(String newText)
        {
            char[] array = newText.toCharArray();
            for (int i = 0; i < array.length; i++)
            {
                if(!Character.isJavaIdentifierPart(array[i]))
                    return "Cannot contain special characters !!";
            }

            IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
            IProject[] projs = root.getProjects();
            for (int i = 0; i < projs.length; i++) {
                if(projs[i].getName().equalsIgnoreCase(newText))
                    return "Project already exist !!";
            }

            /*
                Not checking for special Win32 names like con etc.
            */
            return null;
        }
    });

    if(dialog.open() == Dialog.CANCEL)
        return null;

    return dialog.getValue();
}