1 files changed, 60 insertions, 0 deletions
diff --git a/src/main/model/util/EventLog.java b/src/main/model/util/EventLog.java
new file mode 100644
index 0000000..507c9b2
--- /dev/null
+++ b/src/main/model/util/EventLog.java
@@ -0,0 +1,60 @@
+package model.util;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+
+/**
+ * Represents a log of alarm system events.
+ * We use the Singleton Design Pattern to ensure that there is only
+ * one EventLog in the system and that the system has global access
+ * to the single instance of the EventLog.
+ */
+public class EventLog implements Iterable<Event> {
+    /** the only EventLog in the system (Singleton Design Pattern) */
+    private static EventLog theLog;
+    private Collection<Event> events;
+
+    /**
+     * Prevent external construction.
+     * (Singleton Design Pattern).
+     */
+    private EventLog() {
+        events = new ArrayList<Event>();
+    }
+
+    /**
+     * Gets instance of EventLog - creates it
+     * if it doesn't already exist.
+     * (Singleton Design Pattern)
+     * @return  instance of EventLog
+     */
+    public static EventLog getInstance() {
+        if (theLog == null) {
+            theLog = new EventLog();
+        }
+
+        return theLog;
+    }
+
+    /**
+     * Adds an event to the event log.
+     * @param e the event to be added
+     */
+    public void logEvent(Event e) {
+        events.add(e);
+    }
+
+    /**
+     * Clears the event log and logs the event.
+     */
+    public void clear() {
+        events.clear();
+        logEvent(new Event("Event log cleared."));
+    }
+
+    @Override
+    public Iterator<Event> iterator() {
+        return events.iterator();
+    }
+}