001package bradleyross.library.applets; 002// colorsSample.java 003// A simple Java applet 004// 005import java.awt.*; 006import java.applet.Applet; 007import java.applet.AppletContext; 008import java.awt.Button; 009import java.awt.event.ActionListener; 010import java.awt.event.ActionEvent; 011import bradleyross.library.helpers.FileHelpers; 012import java.io.IOException; 013import java.io.StringReader; 014import java.io.LineNumberReader; 015import java.net.MalformedURLException; 016import java.net.URL; 017import java.util.Vector; 018// 019/** 020 * Demonstrates using a Java applet to display web pages in windows 021 * on the browser. 022 * <p>This Java file can be compiled using 023 * <code>-source 1.3 -target 1.3</code> 024 * so that it will run with browsers using Java Run-Time 025 * Environments as early as Java 1.3. However, the standard 026 * script now uses version 1.5 as the standard.</p> 027 * @see java.awt.Button 028 * @see java.awt.Canvas 029 * @see java.awt.Panel 030 * @see java.awt.GridBagConstraints 031 * @see java.awt.GridBagLayout 032 * @author Bradley Ross 033 */ 034public class WebSample extends Applet implements ActionListener 035{ 036 /** 037 * Inserted to satisfy Serializable interface. 038 */ 039 private static final long serialVersionUID = 1L; 040 protected AppletContext context = null; 041 protected String listUrl = null; 042 protected String listUrlArray[] = null; 043 protected URL rootUrl = null; 044 protected URL url = null; 045 /** 046 * The inner class colorSet represents the buttons in the panel 047 * which the user sees. 048 * <p>Each of the buttons is defined as a public field in the inner class, with each 049 * field belonging to the class java.awt.Button. The entire panel containing 050 * the buttons is also defined as a public field, with the field of type 051 * java.awt.Panel.</p> 052 */ 053 class colorSet extends Component 054 { 055 056 /** 057 * 058 */ 059 private static final long serialVersionUID = 1L; 060 /** 061 * Integer value representing the button that 062 * was depressed. 063 */ 064 public int ColorChoice; 065 /** 066 * Object defining the panel of buttons. 067 */ 068 Panel colorPanel = new Panel(); 069 /** 070 * Object for the "black" button. 071 *<p>The other buttons are defined in the same manner.</p> 072 */ 073 public Button blackButton = new Button("black"); 074 /** 075 * Object for the "blue" button. 076 *<p>The actions in the constructor for blueButton 077 * differ from the other in that the label is 078 * changed to " Blue " while the message returned 079 * to the listener is still "blue".</p> 080 */ 081 public Button blueButton = new Button("blue"); 082 /** See the description of blackButton */ 083 public Button cyanButton = new Button("cyan"); 084 /** See the description of blackButton */ 085 public Button darkGrayButton = new Button("darkGray"); 086 /** See the description of blackButton */ 087 public Button grayButton = new Button("gray"); 088 /** See the description of blackButton */ 089 public Button lightGrayButton = new Button("lightGray"); 090 /** See the description of blackButton */ 091 public Button magentaButton = new Button("magenta"); 092 /** See the description of blackButton */ 093 public Button orangeButton = new Button("orange"); 094 /** See the description of blackButton */ 095 public Button pinkButton = new Button("pink"); 096 /** See the description of blackButton */ 097 public Button redButton = new Button("red"); 098 /** See the description of blackButton */ 099 public Button whiteButton = new Button("white"); 100 /** See the description of blackButton */ 101 public Button yellowButton = new Button("yellow"); 102 /** See the description of blackButton */ 103 public Button greenButton = new Button("green"); 104 /** 105 * This is the constructor for the colorSet class 106 * which defines the buttons. 107 *<p>For blackButton, the setLabel and setActionCommand 108 * methods are used to set the values.</p> 109 *<p>For the other buttons, label for the button and 110 * the message returned when the button is depressed 111 * are set equal to the string used in the constructor 112 * for the java.awt.Button object.</p> 113 *<p>The add method for the colorPanel object places the 114 * various buttons in the panel according to the 115 * GridBagLayout and GridBagConstraints classes.</p> 116 */ 117 public colorSet() 118 { 119 ColorChoice = 1; 120 setBackground(Color.white); 121 GridBagLayout layout = new GridBagLayout(); 122 GridBagConstraints constraints = new GridBagConstraints(); 123 colorPanel.setLayout(layout); 124 constraints.insets = new Insets (5, 5, 5, 5); 125 constraints.fill = GridBagConstraints.BOTH; 126 constraints.anchor = GridBagConstraints.SOUTHWEST; 127 constraints.weightx = 0; constraints.weighty = 0; 128 constraints.gridwidth = 1; constraints.gridheight = 1; 129 // 130 constraints.gridx = 1; constraints.gridy = 1; 131 colorPanel.add(blackButton, constraints); 132 // 133 constraints.gridx = 2; constraints.gridy = 1; 134 colorPanel.add(blueButton, constraints); 135 blueButton.setLabel(" Blue "); 136 blueButton.setActionCommand("blue"); 137 // 138 constraints.gridx = 3; constraints.gridy = 1; 139 colorPanel.add(cyanButton, constraints); 140 // 141 constraints.gridx = 4; constraints.gridy = 1; 142 colorPanel.add(darkGrayButton, constraints); 143 // 144 constraints.gridx = 5; constraints.gridy = 1; 145 colorPanel.add(grayButton, constraints); 146 // 147 constraints.gridx = 1; constraints.gridy = 2; 148 colorPanel.add(greenButton, constraints); 149 // 150 constraints.gridx = 2; constraints.gridy = 2; 151 colorPanel.add(lightGrayButton, constraints); 152 // 153 constraints.gridx = 3; constraints.gridy = 2; 154 colorPanel.add(magentaButton, constraints); 155 // 156 constraints.gridx = 4; constraints.gridy = 2; 157 colorPanel.add(orangeButton, constraints); 158 // 159 constraints.gridx = 5; constraints.gridy = 2; 160 colorPanel.add(pinkButton, constraints); 161 // 162 constraints.gridx = 1; constraints.gridy = 3; 163 colorPanel.add(redButton, constraints); 164 // 165 constraints.gridx = 2; constraints.gridy = 3; 166 colorPanel.add(whiteButton, constraints); 167 // 168 constraints.gridx = 3; constraints.gridy = 3; 169 colorPanel.add(yellowButton, constraints); 170 } 171 } // This is the end of the inner class 172 static final String message = "Hello World!"; 173 static final String errorMessage = "Illegal Code"; 174 175 /** 176 * The buttons object is the instantiation of the inner class colorSet. 177 */ 178 colorSet buttons = new colorSet(); 179 /** 180 * Initialize the applet. 181 *<p>The class colorsSample implements the interface 182 * java.awt.ActionListener as well as extending the 183 * class java.applet.Applet.</p> 184 *<p>The addActionListener methods arrange for the 185 * colorsSample class to receive the messages 186 * when the buttons are depressed. This means that 187 * that the ActionPerformed method for the class 188 * is executed whenever a button is depressed.</p> 189 * @see java.awt.event.ActionListener 190 * @see java.applet.Applet 191 */ 192 public void init() 193 { 194 System.out.println("Starting program"); 195 196 197 listUrl = getParameter("ImageList"); 198 rootUrl = getDocumentBase(); 199 if (listUrl != null) 200 { 201 try 202 { 203 String urlFile = FileHelpers.readTextFile(new URL(rootUrl, listUrl)); 204 LineNumberReader reader = new LineNumberReader(new StringReader(urlFile)); 205 Vector<String> urlSet = new Vector<String>(); 206 while (true) 207 { 208 String temp = reader.readLine(); 209 if (temp == null) { break; } 210 if (temp.length() == 0) { continue; } 211 urlSet.add(temp); 212 } 213 } 214 catch (MalformedURLException e) 215 { 216 showStatus(e.getClass().getName()); 217 } 218 catch (IOException e) 219 { 220 showStatus(e.getClass().getName()); 221 } 222 } 223 context = this.getAppletContext(); 224 FlowLayout layout = new FlowLayout(); 225 setLayout(layout); 226 setBackground(Color.white); 227 add(buttons.colorPanel); 228 buttons.blackButton.addActionListener(this); 229 buttons.blueButton.addActionListener(this); 230 buttons.cyanButton.addActionListener(this); 231 buttons.darkGrayButton.addActionListener(this); 232 buttons.grayButton.addActionListener(this); 233 buttons.greenButton.addActionListener(this); 234 buttons.lightGrayButton.addActionListener(this); 235 buttons.magentaButton.addActionListener(this); 236 buttons.orangeButton.addActionListener(this); 237 buttons.pinkButton.addActionListener(this); 238 buttons.redButton.addActionListener(this); 239 buttons.whiteButton.addActionListener(this); 240 buttons.yellowButton.addActionListener(this); 241 doLayout(); 242 System.out.println("Layout complete"); 243 } // End of init 244 /** 245 * The paint method is called whenever it is necessary to 246 * redraw the contents of the applet. 247 * <p>The paint method is called whenever it is necessary 248 * redraw the image. It can be called by the window manager 249 * when a window is resized, covered, or uncovered or when it 250 * detects that another method has executed the repaint method.</p> 251 * @param g The graphics item which is to be redrawn. 252 */ 253 /** 254 * The actionPerformed method is executed whenever 255 * an action is taken by the user. 256 *<p>The event created by depressing the 257 * the button is passed as argument of 258 * the method and the getActionCommand method 259 * obtains the character string associated 260 * with the button as defined by the constructor 261 * and other methods for the button.</p> 262 *<p>This method then sets the ColorChoice field 263 * in the buttons object according to which 264 * button was depressed and then uses the 265 * repaint method to cause the graphics on the 266 * applet to be redrawn.</p> 267 */ 268 public void actionPerformed (ActionEvent e) 269 { 270 String command = new String(); 271 command = e.getActionCommand(); 272 System.out.println("ActionEvent **" + command + "**"); 273 URL test = null; 274 try 275 { 276 test = new URL(rootUrl, "colors/" + command.toLowerCase() + ".html"); 277 } 278 catch (MalformedURLException e1) 279 { 280 System.out.println(e1.getClass().getName() + " " + e1.getMessage()); 281 } 282 context.showDocument(test, "pages"); 283 } // end of actionPerformed 284}