Developing Simple Chess Board With SWT

I have worked with AWT, Swing and SWT in different projects. I was involved last 2 years mostly on web applications and hence after joining Philips, I got a chance to work with thick clients again. Here I developed a simple prototype for SWT beginners with step by step instructions to develop a chess board using SWT and 3 different ways to setup environment, compile and run it. Hope you will enjoy!

1. Make sure you have Java installed. I installed Java SE 5 in C:\programs\java\jdk_1.5.0.7
2. Install Ant 1.6.5 altough you may use command prompt if you dont want to use Ant or even better if you use Eclipse which already has Ant functionalities to work with Ant. I installed Ant at C:\programs\java\apache-ant-1.6.5
3. Create project directory at c:\workspace\SWTBoard either manually or using Eclipse New Java Project.
4. Download SWT jar file from Eclipse web site – http://www.eclipse.org/swt . If you already have Eclipse installed in your machine then, you will find the JAR file inside $Eclipse_Install_dir$\plugins directory. I am using SWT 3.2.1 for Windows.
5. Copy the jar file to a suitable directory for easy reference. I copied the org.eclipse.swt.win32.win32.x86_3.2.1.v3235.jar file (or swt.jar if you have downloaded from Eclipse web site) in C:\workspace\swtlibs directory.
6. Extract swt-win32-3235.dll file inside the SWT jar file and copy it into the same directory.
7. Create SWTBoard class under package name com.chess4you.board. Here is the source code for this class.
   /** SWTBoard.java **/
   package com.chess4you.board;
   import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell;
   import org.eclipse.swt.widgets.Label; import org.eclipse.swt.graphics.Color;
   import org.eclipse.swt.graphics.Image;
   import org.eclipse.swt.graphics.ImageData;
   import org.eclipse.swt.graphics.Rectangle;
   import org.eclipse.swt.layout.GridData;
   import org.eclipse.swt.layout.GridLayout;
   import org.eclipse.swt.SWT;/**
   * A simple chess board developed using SWT
   *
   * @author Ashik Uzzaman
   * @link http://ashikuzzaman.wordpress.com
   */
   public class SWTBoard { public static final int NUMBER_OF_ROWS = 8;
   public static final int NUMBER_OF_FILES = 8;
   public static Display display = new Display();
   public static Shell shell = new Shell(display, SWT.SHELL_TRIM);
   public static GridLayout layout = new GridLayout();
   public static GridData data;
   public static Label square;
   
   private static void createSquares() {
   for(int i=NUMBER_OF_ROWS; i>0; i–) {
   for(int j=1; j<=NUMBER_OF_FILES; j++) {
   data = new GridData(GridData.FILL_BOTH);
   square = new Label(shell, SWT.CENTER);
   square.setBounds(shell.getClientArea());
   square.setBackground(getColor(i, j));
   square.setText(“r” + i + “:c” + j);
   square.setForeground(new Color(display, 0, 0, 250));
   square.setToolTipText(“Row ” + i + ” and Column ” + j);
   square.setLayoutData(data);
   }
   }
   } private static Color getColor(int x, int y)
   {
   if((x+y) % 2 == 0)
   return new Color(display, 255, 255, 255);
   else
   return new Color(display, 0, 0, 0);
   }
   
   /**
   * @param args
   */
   public static void main(String[] args) {
   layout.numColumns = NUMBER_OF_FILES;
   layout.makeColumnsEqualWidth = true;
   int squareSize = 0;
   int width = display.getBounds().width;
   int height = display.getBounds().height;
   if(width >= height) {
   squareSize = height / 2;
   } else {
   squareSize = width / 2;
   }
   shell.setSize(squareSize, squareSize);
   shell.setBounds(new Rectangle(squareSize / 4, squareSize / 4, squareSize, squareSize));
   shell.setLayout(layout);
   ImageData imgData = new ImageData(“board.jpg”);
   Image img = new Image(display, imgData, imgData);
   shell.setImage(img);
   
   createSquares();

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

8. Create javase5.bat file inside your project directory. The content of this file actually sets path and classpath required for java and SWT.
   ## Simple batch file for Java classpath settings
   SET JAVA_HOME=C:\programs\java\jdk_1.5.0.7
   SET ANT_HOME=C:\programs\java\apache-ant-1.6.5
   SET PATH=%PATH%;%JAVA_HOME%\bin;%ANT_HOME%\bin
   SET PROJECT_HOME=C:\workspace\SWTBoard
   SET CLASSPATH=%CLASSPATH%;.;%JAVA_HOME%\lib\tools.jar;C:\workspace\swtlibs\org.eclipse.swt.win32.win32.x86_3.2.1.v3235.jar Title “JDK 5″
   cd %PROJECT_HOME%
   cmd
9. If you use Ant or Eclipse, create build.xml file in your project directory with following contents.
   <?xml version=”1.0″ encoding=”ISO-8859-1″?>
   <project name=”GenericSwtApplication” default=”run” basedir=”.”>
   <description> SWT Application build and execution file </description> <property name=”main.class” value=”com.chess4you.board.SWTBoard”/>
   <property name=”src” location=”.”/>
   <property name=”build” location=”.”/>
   <property name=”swt.libs” value=”C:\workspace\swtlibs”/>
   
   <property name=”swt.jar.lib” location=”${swt.libs}”/>
   <property name=”swt.jni.lib” location=”${swt.libs}”/>
   
   <path id=”project.class.path”>
   <pathelement path=”${build}”/>
   <fileset dir=”${swt.jar.lib}”>
   <include name=”**/*.jar”/>
   </fileset>
   </path> <target name=”compile”>
   <javac srcdir=”${src}” destdir=”${build}”>
   <classpath refid=”project.class.path”/>
   </javac>
   </target> <target name=”run” depends=”compile”>
   <java classname=”${main.class}” fork=”true” failonerror=”true”>
   <jvmarg value=”-Djava.library.path=${swt.jni.lib}”/>
   <classpath refid=”project.class.path”/>
   </java>
   </target>
   </project>
10. Copy a small icon for a chess board in your project directory and name it board.jpg that is used in our code. You may download the icon that I used from http://farm1.static.flickr.com/160/391341494_669254c2c6_s.jpg
11. To compile from command prompt, double click javase5.bat file and issue the following command: javac com/chess4you/board/SWTBoard.java
12. To run from command prompt, issue the following command: java -Djava.library.path=C:\workspace\swtlibs com.chess4you.board.SWTBoard
13. To compile using Ant, issue the following command: ant compile
14. To run using Ant, issue the following command: ant run
15. To compile/build the project using Eclipse, you have to first add the SWT jar file in your project classpath. To do so, right-click on your project in package explorer and select Properties->Java Build Path->Libraries->Add External Jars… and add C:\workspace\swtlibs\org.eclipse.swt.win32.win32.x86_3.2.1.v3235.jar . Now you should be able to build the project selecting Project->Build Project .
    
16. To run the project using Eclipse, select Run->Run… ->Arguments and in VM Arguments text area add the following entry: -Djava.library.path=C:/workspace/swtlibs
17. You may also use the Ant build file (build.xml) from Eclipse by double-clicking on it and running the specific targets (compile or run) by right-click on the target and selecting Run As->Ant Build.