001 /*
002 * Calculator GUI
003 *
004 * Developed for "Rethinking CS101", a project of Lynn Andrea Stein's AP Group.
005 * For more information, see <a href="http://www.ai.mit.edu/projects/cs101/">the
006 * CS101 homepage</a> or email <las@ai.mit.edu>.
007 *
008 * Copyright (C) 1996 Massachusetts Institute of Technology.
009 * Please do not redistribute without obtaining permission.
010 */
011 package calculator;
012
013 import java.awt.*;
014 import java.awt.event.*;
015 import cs101.util.semaphore.IntBuffer;
016
017 /**
018 * This is an implementation of the GUI for a basic four-function
019 * calculator. It relies on a ButtonHandler (Runnable) to repeatedly
020 * call getButton() and consume the buttonIDs that the Calculator
021 * object produces.
022 *
023 * <P>This follows the interactive-control-loop design described in the
024 * early parts of 6.096 and as a part of the
025 * <a href="http://www.ai.mit.edu/projects/cs101/">
026 * Rethinking CS101
027 * </a> project of Lynn Andrea Stein's AP Group at the MIT
028 * Artificial Intelligence Laboratory.
029 *
030 * <P>Copyright (c) 1998 Massachusetts Institute of Technology
031 *
032 * @author: Todd C. Parnell, tparnell@ai.mit.edu
033 * @author: Emil Sit, sit@mit.edu
034 * @author: Lynn Andrea Stein, las@ai.mit.edu
035 * @version: $Id: CalculatorGUI.java,v 1.1.1.1 2002/06/05 21:56:34 root Exp $
036 *
037 * @see calculator.ButtonHandler
038 * @see cs101.util.semaphore.IntBuffer
039 *
040 */
041
042 public class CalculatorGUI extends Frame implements Calculator {
043
044 /**
045 * The "screen" of the calculator. Private -- do not use.
046 */
047 private TextField display;
048
049 /**
050 * Synchronized storage for put/getButton. Private -- do not use.
051 * Note: currently package visible becuase buttonBuf is used by an
052 * inner class. This is a workaround for a bug in the JDK. (6 July 98)
053 */
054 /* private */ IntBuffer buttonBuf = new IntBuffer();
055
056 /**
057 * The Button components themselves. Private -- do not use.
058 */
059 private Button[] Buttons = new Button[Calculator.LAST];
060
061 // Set up the labels w/ static initializer (only need to do this once).
062 static {
063 for ( int i = 0; i < 10; i++ ) {
064 ButtonLabels[i] = String.valueOf( i );
065 }
066 ButtonLabels[Calculator.OP_DIV] = "/";
067 ButtonLabels[Calculator.OP_MUL] = "*";
068 ButtonLabels[Calculator.OP_ADD] = "+";
069 ButtonLabels[Calculator.OP_SUB] = "-";
070 ButtonLabels[Calculator.DOT] = ".";
071 ButtonLabels[Calculator.EQUALS] = "=";
072 ButtonLabels[Calculator.CLEAR] = "clear";
073 }
074
075 /**
076 * Initialize components and such at runtime. Automagically called
077 * by the java runtime. You should not use it.
078 */
079 public CalculatorGUI() {
080 super("CS101 Calculator");
081
082 this.setLayout( new GridLayout( 0, 1 ) );
083
084 this.display = new TextField("");
085 this.display.setEditable( false );
086 this.display.setBackground( Color.white );
087 this.display.setForeground( Color.blue );
088 this.display.setFont( new Font("Monospaced", Font.BOLD, 24) );
089 this.display.setCursor( new Cursor(Cursor.HAND_CURSOR) );
090
091 this.add( this.display );
092
093 for ( int i = 0; i < Calculator.LAST; i++ ) {
094 this.Buttons[i] = new Button( Calculator.ButtonLabels[i] );
095 // Add the ActionListener for this button
096 this.Buttons[i].addActionListener(new ActionListener() {
097 public void actionPerformed(ActionEvent e) {
098 // Find out what button was pressed. We cannot (unfortunately)
099 // simply use "i" here, so we do it the hard way.
100 String label = ((Button)e.getSource()).getLabel();
101 for ( int k = 0; k < Calculator.LAST; k++ ) {
102 if (Calculator.ButtonLabels[k].equals(label)) {
103 CalculatorGUI.this.buttonBuf.putButton( k );
104 break; // only one match is possible
105 }
106 }
107 }
108 });
109 }
110 // Layout the keypad one row at a time.
111 Panel numberPad = new Panel();
112 numberPad.setBackground( Color.lightGray );
113 numberPad.setForeground( Color.black );
114 numberPad.setFont( new Font("Monospaced", Font.BOLD, 20) );
115 numberPad.setCursor( new Cursor(Cursor.HAND_CURSOR) );
116
117 numberPad.setLayout( new GridLayout( 0, 4, 1, 1 ) );
118 numberPad.add( this.Buttons[7] ); // Row 1
119 numberPad.add( this.Buttons[8] );
120 numberPad.add( this.Buttons[9] );
121 numberPad.add( this.Buttons[Calculator.OP_DIV] );
122 numberPad.add( this.Buttons[4] ); // Row 2
123 numberPad.add( this.Buttons[5] );
124 numberPad.add( this.Buttons[6] );
125 numberPad.add( this.Buttons[Calculator.OP_MUL] );
126 numberPad.add( this.Buttons[1] ); // Row 3
127 numberPad.add( this.Buttons[2] );
128 numberPad.add( this.Buttons[3] );
129 numberPad.add( this.Buttons[Calculator.OP_ADD] );
130 numberPad.add( this.Buttons[0] ); // Row 4
131 numberPad.add( this.Buttons[Calculator.DOT] );
132 numberPad.add( this.Buttons[Calculator.EQUALS] );
133 numberPad.add( this.Buttons[Calculator.OP_SUB] );
134 numberPad.add( new Button("") ); // Row 5
135 numberPad.add( new Button("") );
136 numberPad.add( new Button("") );
137 numberPad.add( this.Buttons[Calculator.CLEAR] ); // --BIG button
138 this.add( numberPad );
139
140 this.pack(); // Set the window size,
141 this.show(); // pop it up,
142 this.validate(); //
143 this.setResizable(false); //
144
145
146 this.addWindowListener( new WindowAdapter() {
147 public void windowClosing( WindowEvent e) {
148 System.out.println("Exiting...");
149 CalculatorGUI.this.dispose();
150 System.exit(0);
151 }
152 });
153
154 }
155
156 /**
157 * Get the next Button pressed. The return value will be an int
158 * between 0 and 9 (if the button was a number) or one of the
159 * Calculator constants.
160 *
161 * @return the next button to be handled.
162 */
163 public int getButton() {
164 return this.buttonBuf.getButton();
165 }
166
167 /**
168 * Get the label for the given Button ID. The argument
169 * should be an int between 0 and 9 (if the button was
170 * a number) or one of the Calculator constants,
171 * otherwise the empty string ("") will be returned.
172 *
173 * @return the button label as a String.
174 */
175 public String getButtonLabel(int buttonID) {
176 if ((buttonID < 0) || (buttonID > Calculator.LAST)) {
177 return "";
178 } else {
179 return ButtonLabels[buttonID];
180 }
181 }
182
183 /**
184 * Get the text currently displayed on the Calculator.
185 *
186 * @return the text as a String.
187 */
188 public String getText() {
189 return this.display.getText();
190 }
191
192
193 /**
194 * Set the text currently displayed on the Calculator.
195 *
196 * @param newText the text to be displayed.
197 */
198 public void setText( String newText ) {
199 this.display.setText( newText );
200 }
201 }
202
203 /* Comments:
204 *
205 * History:
206 * $Log: CalculatorGUI.java,v $
207 * Revision 1.1.1.1 2002/06/05 21:56:34 root
208 * CS101 comes to Olin finally.
209 *
210 * Revision 1.3 2000/05/01 06:25:19 mharder
211 * Changed javadoc to agree with new cs101 packages.
212 *
213 * Revision 1.2 2000/04/25 17:45:34 nathanw
214 * Adapt to new cs101.* layout
215 *
216 * Revision 1.1 1999/10/08 15:09:24 las
217 * This pset replaces the old Calculator pset. However, not everything
218 * has been transferred. At the moment, it's just java, doc, and index.
219 * The rest are still in the repository under Calculator-Old.
220 *
221 * Revision 1.6 1998/07/24 16:37:14 tparnell
222 * Placate new javadoc behavior
223 *
224 * Revision 1.5 1998/07/21 14:58:44 tparnell
225 * javadoc fix
226 *
227 * Revision 1.4 1998/07/07 14:22:00 tparnell
228 * changed refrences to Frame.HAND_CURSOR to Cursor.HAND_CURSOR
229 *
230 * Revision 1.3 1998/07/06 20:08:32 tparnell
231 * removed some JDK1.0 code still present in file. minor redesign of event
232 * handling. CalculatorGUI used to implement ActionListener and handled
233 * events from the various buttons. Now that work is done by an anonymous
234 * inner class.
235 *
236 * Revision 1.2 1998/06/05 05:19:29 craigh
237 * added getButtonLabel() to Calculator interface. Implemented the
238 * method in CalculatorGUI, and made use of it in ButtonHandler.
239 *
240 * Revision 1.1 1998/02/26 17:25:45 tparnell
241 * Reconstruction from hard drive failure. Everything appears intact.
242 *
243 * Revision 1.3 1997/10/05 21:11:20 shong
244 * Updated for fall97, to Java 1.1
245 * changed GUI, using 1.1 Event Model
246 *
247 * Revision 1.2 1997/07/16 14:15:21 tparnell
248 * *** empty log message ***
249 *
250 * Revision 1.2 1996/10/04 19:02:26 las
251 * Fixed the location of the clear button so that it's not quite so
252 * grotesque. (I suppose that the right answer is a GridBagLayout....)
253 *
254 * Revision 1.1 1996/10/04 16:20:21 las
255 * Transformed Calculator into an application and made it a package. See
256 * STAFF_SETUP for which files are public. To run, use Calculator.Main.
257 *
258 * Specifics:
259 * Added Main.java, which starts the calculator program (both
260 * CalculatorGUI and ButtonHandler);
261 * Made Calculator an interface;
262 * Moved GUI implementation (previously in Calculator) to
263 * CalculatorGUI.
264 * Added clear button, which looks pretty gross right now. (It can
265 * be deleted in a single line, though.)
266 *
267 * Revision 1.1.1.1 1996/07/18 17:26:12 sit
268 * Import from summer 6.80s web tree
269 *
270 *
271 */
272