initial commit

clock/src/ClockMain.java

@@ -0,0 +1,26 @@
+import clock.AlarmClockEmulator;
+import clock.io.Choice;
+import clock.io.ClockInput;
+import clock.io.ClockInput.UserInput;
+import clock.io.ClockOutput;
+
+public class ClockMain {
+    public static void main(String[] args) throws InterruptedException {
+        AlarmClockEmulator emulator = new AlarmClockEmulator();
+
+        ClockInput  in  = emulator.getInput();
+        ClockOutput out = emulator.getOutput();
+
+        out.displayTime(15, 2, 37);   // arbitrary time: just an example
+
+        while (true) {
+            UserInput userInput = in.getUserInput();
+            Choice c = userInput.choice();
+            int h = userInput.hours();
+            int m = userInput.minutes();
+            int s = userInput.seconds();
+
+            System.out.println("choice=" + c + " h=" + h + " m=" + m + " s=" + s);
+        }
+    }
+}

clock/src/clock/io/Choice.java

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+package clock.io;
+
+public enum Choice {
+    SET_TIME,        // user set new clock time
+    SET_ALARM,       // user set new alarm time
+    TOGGLE_ALARM;    // user pressed both buttons simultaneously
+}

clock/src/clock/io/ClockInput.java

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+package clock.io;
+
+import java.util.concurrent.Semaphore;
+
+/**
+ * Input signals from clock hardware.
+ * 
+ * NOTE: you are not expected to modify this interface,
+ * nor to implement it yourself. Instead, to read from
+ * the emulated hardware, do as follows:
+ * 
+ *   AlarmClockEmulator emulator = new AlarmClockEmulator();
+ *   ClockInput in = emulator.getInput();
+ *
+ * Then use the reference 'in' to read the input signals.
+ */
+public interface ClockInput {
+
+    /** @return  semaphore signaled on user input (via hardware interrupt) */
+    Semaphore getSemaphore();
+
+    /** @return  an item of user input (available only when semaphore is signaled) */
+    UserInput getUserInput();
+
+    // -----------------------------------------------------------------------
+    
+    /** An item of input, entered by the user. */
+    interface UserInput {
+        /** @return  a value indicating the type of choice made by the user. */
+        Choice choice();
+    
+        /**
+         * These methods return a time set by the user (clock time or alarm time).
+         * 
+         * If choice() returns SET_TIME, these return the time the user entered.
+         * If choice() returns SET_ALARM, these return the alarm time the user entered.
+         * If choice() returns TOGGLE_ALARM, these return an invalid value.
+         */
+        int hours();
+        int minutes();
+        int seconds();
+    }
+}

clock/src/clock/io/ClockOutput.java

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+package clock.io;
+
+/**
+ * Output signals to clock hardware.
+ * 
+ * NOTE: you are not expected to modify this interface,
+ * nor to implement it yourself. Instead, to control
+ * the emulated hardware, do as follows:
+ * 
+ *   AlarmClockEmulator emulator = new AlarmClockEmulator();
+ *   ClockInput out = emulator.getoutput();
+ *
+ * Then use the reference 'out' to control the output signals.
+*/
+public interface ClockOutput {
+
+    /** Display the given time on the display, for example (15, 2, 37) for
+        15 hours, 2 minutes and 37 seconds since midnight. */
+    void displayTime(int hours, int mins, int secs);
+
+    /** Indicate on the display whether the alarm is on or off. */
+    void setAlarmIndicator(boolean on);
+
+    /** Signal the alarm. (In the emulator, only a visual alarm is given.) */
+    void alarm();
+}