001 /*
002 * Calculator GUI
003 *
004 * Developed for "Rethinking CS101", a project of Lynn Andrea Stein's.
005 * For more information, see <a href="http://www.cs101.org/">the
006 * CS101 homepage</a> or email <las@olin.edu>.
007 *
008 * Copyright (C) 1996 Massachusetts Institute of Technology.
009 * Please do not redistribute without obtaining permission.
010 */
011 package calculator;
012 import java.awt.*;
013 import java.awt.event.*;
014 import cs101.util.semaphore.IntBuffer;
015
016 /**
017 * This is an implementation of the GUI for a basic four-function
018 * calculator. It relies on a ButtonHandler (Runnable) to repeatedly
019 * call getButton() and consume the buttonIDs that the Calculator
020 * object produces. <p>
021 *
022 * This follows the interactive-control-loop design described in the
023 * early parts of PI and as a part of the
024 * <a href="http://www.cs101.org/">
025 * Rethinking CS101
026 * </a> project of Lynn Andrea Stein's AP Group at Olin College.
027 * <p>
028 *
029 *
030 * @see ButtonHandler
031 * @see cs101.util.semaphore.IntBuffer
032 *
033 */
034
035 public class CalculatorGUI extends Frame implements ActionListener, Calculator {
036
037 /**
038 * The "screen" of the calculator. Private -- do not use.
039 */
040 private TextField display;
041
042 /**
043 * Synchronized storage for put/getButton. Private -- do not use.
044 */
045 private IntBuffer buttonBuf = new IntBuffer();
046
047 /**
048 * The Button components themselves. Private -- do not use.
049 */
050 private Button[] Buttons = new Button[Calculator.LAST];
051
052 // Set up the labels w/ static initializer (only need to do this once).
053 static {
054 for ( int i = 0; i < 10; i++ ) {
055 ButtonLabels[i] = String.valueOf( i );
056 }
057 ButtonLabels[Calculator.OP_DIV] = "/";
058 ButtonLabels[Calculator.OP_MUL] = "*";
059 ButtonLabels[Calculator.OP_ADD] = "+";
060 ButtonLabels[Calculator.OP_SUB] = "-";
061 ButtonLabels[Calculator.DOT] = ".";
062 ButtonLabels[Calculator.EQUALS] = "=";
063 ButtonLabels[Calculator.CLEAR] = "clear";
064 }
065
066 /**
067 * Initialize components and such at runtime. Automagically called
068 * by the java runtime. You should not use it.
069 */
070 public CalculatorGUI() {
071 super("CS101 Calculator");
072
073 this.setLayout( new GridLayout( 0, 1 ) );
074
075 this.display = new TextField("");
076 this.display.setEditable( false );
077 this.display.setBackground( Color.white );
078 this.display.setForeground( Color.blue );
079 this.display.setFont( new Font("Monospaced", Font.BOLD, 24) );
080 this.display.setCursor( new Cursor(HAND_CURSOR) );
081
082 this.add( this.display );
083
084 for ( int i = 0; i < Calculator.LAST; i++ ) {
085 this.Buttons[i] = new Button( Calculator.ButtonLabels[i] );
086 this.Buttons[i].addActionListener(this);
087 }
088 // Layout the keypad one row at a time.
089 Panel numberPad = new Panel();
090 numberPad.setBackground( Color.lightGray );
091 numberPad.setForeground( Color.black );
092 numberPad.setFont( new Font("Monospaced", Font.BOLD, 20) );
093 numberPad.setCursor( new Cursor(HAND_CURSOR) );
094
095 numberPad.setLayout( new GridLayout( 0, 4, 1, 1 ) );
096 numberPad.add( this.Buttons[7] ); // Row 1
097 numberPad.add( this.Buttons[8] );
098 numberPad.add( this.Buttons[9] );
099 numberPad.add( this.Buttons[Calculator.OP_DIV] );
100 numberPad.add( this.Buttons[4] ); // Row 2
101 numberPad.add( this.Buttons[5] );
102 numberPad.add( this.Buttons[6] );
103 numberPad.add( this.Buttons[Calculator.OP_MUL] );
104 numberPad.add( this.Buttons[1] ); // Row 3
105 numberPad.add( this.Buttons[2] );
106 numberPad.add( this.Buttons[3] );
107 numberPad.add( this.Buttons[Calculator.OP_ADD] );
108 numberPad.add( this.Buttons[0] ); // Row 4
109 numberPad.add( this.Buttons[Calculator.DOT] );
110 numberPad.add( this.Buttons[Calculator.EQUALS] );
111 numberPad.add( this.Buttons[Calculator.OP_SUB] );
112 numberPad.add( new Button("") ); // Row 5
113 numberPad.add( new Button("") );
114 numberPad.add( new Button("") );
115 numberPad.add( this.Buttons[Calculator.CLEAR] ); // --BIG button
116 this.add( numberPad );
117
118 this.pack(); // Set the window size,
119 this.show(); // pop it up,
120 this.validate(); //
121 this.setResizable(false); //
122
123
124 this.addWindowListener( new WindowAdapter() {
125 public void windowClosing( WindowEvent e) {
126 System.out.println("Exiting...");
127 CalculatorGUI.this.dispose();
128 System.exit(0);
129 }
130 });
131
132
133 // Java 1.1 Event Model: To handle WINDOW_CLOSING event,
134 // i.e., cleanly kill this application, either need (1) the
135 // above event listener implemented as an anonymous inner
136 // class OR (2) the following line and the
137 // 'processWindowEvent' method for low-level event handling,
138
139 this.enableEvents(AWTEvent.WINDOW_EVENT_MASK);
140 }
141
142 /**
143 * Handle WINDOW_CLOSING event, i.e., cleanly kill this
144 * application. Automagically called by the java runtime. You
145 * should not use it.
146 *
147 * Other window events are passed to the superclass (default) event
148 * handling.
149 */
150 public void processWindowEvent( WindowEvent e ) {
151 if (e.getID() == WindowEvent.WINDOW_CLOSING) {
152 System.out.println("Exiting...");
153 this.dispose();
154 System.exit(0);
155 } else {
156 super.processWindowEvent(e);
157 }
158 }
159
160 /**
161 * Handle button pushes by making them available to getButton.
162 * Automagically called by the java runtime. You should not use it.
163 */
164 public void actionPerformed( ActionEvent e ) {
165 /*
166 private String whichButton = new String(
167 e.getActionCommand() );
168
169 */
170 // Java 1.1 Event Model: If no action command string is
171 // explicitly set, 'getActionCommand' returns the button label.
172
173 for ( int i = 0; i < Calculator.LAST; i++ ) {
174 if ( (e.getActionCommand()).equals( ButtonLabels[i] )) {
175 buttonBuf.putButton( i );
176 break; // exit the for loop as soon as we have a match.
177 }
178 }
179 }
180
181 /**
182 * Get the next Button pressed. The return value will be an int
183 * between 0 and 9 (if the button was a number) or one of the
184 * Calculator constants.
185 *
186 * @return the next button to be handled.
187 */
188 public int getButton() {
189 return this.buttonBuf.getButton();
190 }
191
192 /**
193 * Get the text currently displayed on the Calculator.
194 *
195 * @return the text as a String.
196 */
197 public String getText() {
198 return this.display.getText();
199 }
200
201
202 /**
203 * Set the text currently displayed on the Calculator.
204 *
205 * @param newText the text to be displayed.
206 */
207 public void setText( String newText ) {
208 this.display.setText( newText );
209 }
210 }
211
212 /* Comments:
213 *
214 * History:
215 * $Log: CalculatorGUI.java,v $
216 * Revision 1.2 2004/03/26 21:04:11 gus
217 * take ownership
218 *
219 * Revision 1.1 2003/07/10 21:14:43 jon
220 * Initial commit of spring03 calculator source.
221 *
222 * Revision 1.1.1.1 2002/06/05 21:56:24 root
223 * CS101 comes to Olin finally.
224 *
225 * Revision 1.3 1997/10/05 21:11:20 shong
226 * Updated for fall97, to Java 1.1
227 * changed GUI, using 1.1 Event Model
228 *
229 * Revision 1.2 1997/07/16 14:15:21 tparnell
230 * *** empty log message ***
231 *
232 * Revision 1.2 1996/10/04 19:02:26 las
233 * Fixed the location of the clear button so that it's not quite so
234 * grotesque. (I suppose that the right answer is a GridBagLayout....)
235 *
236 * Revision 1.1 1996/10/04 16:20:21 las
237 * Transformed Calculator into an application and made it a package. See
238 * STAFF_SETUP for which files are public. To run, use Calculator.Main.
239 *
240 * Specifics:
241 * Added Main.java, which starts the calculator program (both
242 * CalculatorGUI and ButtonHandler);
243 * Made Calculator an interface;
244 * Moved GUI implementation (previously in Calculator) to
245 * CalculatorGUI.
246 * Added clear button, which looks pretty gross right now. (It can
247 * be deleted in a single line, though.)
248 *
249 * Revision 1.1.1.1 1996/07/18 17:26:12 sit
250 * Import from summer 6.80s web tree
251 *
252 *
253 */
254
255