001 /*
002 * Calculator Interface
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 /**
014 * This is the interface for a basic four-function calculator, as seen
015 * from the perspective of its logic.
016 *
017 * <P>This interface defines an enumerated type, buttonIDs (including
018 * 0...9, which represent themselves), an array of ButtonLabels
019 * suitable for displaying on the GUI, and the three access functions
020 * by which the logic can manipulate the Calculator: getButton,
021 * getText, and setText.
022 *
023 * <P>Copyright (c) 1998 Massachusetts Institute of Technology
024 *
025 * @author: Emil Sit, sit@mit.edu
026 * @author: Lynn Andrea Stein, las@ai.mit.edu
027 * @version: $Id: Calculator.java,v 1.1.1.1 2002/06/05 21:56:34 root Exp $
028 *
029 * @see CalculatorGUI
030 */
031 public interface Calculator {
032 // buttonID constants.
033 // The numbers 0 through 9 should serve as buttonIDs for the respective buttons.
034 /**
035 * No operation in progress.
036 */
037 public static final int NO_OP = -1;
038
039 /**
040 * Calculator division.
041 */
042 public static final int OP_DIV = 10;
043
044 /**
045 * Calculator multiplication.
046 */
047 public static final int OP_MUL = 11;
048
049 /**
050 * Calculator addition.
051 */
052 public static final int OP_ADD = 12;
053
054 /**
055 * Calculator subtraction.
056 */
057 public static final int OP_SUB = 13;
058
059 /**
060 * Calculator decimal point.
061 */
062 public static final int DOT = 14;
063
064 /**
065 * Calculator = button.
066 */
067 public static final int EQUALS = 15;
068
069 /**
070 * Calculator clear button.
071 */
072 public static final int CLEAR = 16;
073
074 /**
075 * One more than the biggest button index.
076 */
077 public static final int LAST = 17;
078
079
080 /**
081 * An array for the button's labels to deal with dispatch cleanly.
082 * You can use this to get the name of the button (i.e., a String).
083 */
084 public static String[] ButtonLabels = new String[Calculator.LAST];
085
086 /**
087 * Get the next Button pressed. The return value will be an int
088 * between 0 and 9 (if the button was a number) or one of the
089 * Calculator constants.
090 *
091 * @return the next button to be handled.
092 */
093 public int getButton();
094
095 /**
096 * Get the label for the given Button ID. The argument
097 * should be an int between 0 and 9 (if the button was
098 * a number) or one of the Calculator constants,
099 * otherwise the empty string ("") will be returned.
100 *
101 * @return the button label as a String.
102 */
103 public String getButtonLabel(int buttonID);
104
105 /**
106 * Get the text currently displayed on the Calculator.
107 *
108 * @return the text as a String.
109 */
110 public String getText();
111
112 /**
113 * Set the text currently displayed on the Calculator.
114 *
115 * @param newText the text to be displayed.
116 */
117 public void setText( String newText );
118
119 }
120
121 /* Comments:
122 *
123 * History:
124 * $Log: Calculator.java,v $
125 * Revision 1.1.1.1 2002/06/05 21:56:34 root
126 * CS101 comes to Olin finally.
127 *
128 * Revision 1.1 1999/10/08 15:09:23 las
129 * This pset replaces the old Calculator pset. However, not everything
130 * has been transferred. At the moment, it's just java, doc, and index.
131 * The rest are still in the repository under Calculator-Old.
132 *
133 * Revision 1.4 1998/07/24 16:37:14 tparnell
134 * Placate new javadoc behavior
135 *
136 * Revision 1.3 1998/07/06 19:08:52 tparnell
137 * *** empty log message ***
138 *
139 * Revision 1.2 1998/06/05 05:19:26 craigh
140 * added getButtonLabel() to Calculator interface. Implemented the
141 * method in CalculatorGUI, and made use of it in ButtonHandler.
142 *
143 * Revision 1.1 1998/02/26 17:25:44 tparnell
144 * Reconstruction from hard drive failure. Everything appears intact.
145 *
146 * Revision 1.3 1997/10/05 21:11:19 shong
147 * Updated for fall97, to Java 1.1
148 * changed GUI, using 1.1 Event Model
149 *
150 * Revision 1.2 1997/07/16 14:15:20 tparnell
151 * *** empty log message ***
152 *
153 * Revision 1.2 1996/10/04 16:20:20 las
154 * Transformed Calculator into an application and made it a package. See
155 * STAFF_SETUP for which files are public. To run, use Calculator.Main.
156 *
157 * Specifics:
158 * Added Main.java, which starts the calculator program (both
159 * CalculatorGUI and ButtonHandler);
160 * Made Calculator an interface;
161 * Moved GUI implementation (previously in Calculator) to
162 * CalculatorGUI.
163 * Added clear button, which looks pretty gross right now. (It can
164 * be deleted in a single line, though.)
165 *
166 * Revision 1.1.1.1 1996/07/18 17:26:12 sit
167 * Import from summer 6.80s web tree
168 *
169 *
170 */
171