aboutsummaryrefslogtreecommitdiff
path: root/src/main/model/util/EventLog.java
diff options
context:
space:
mode:
Diffstat (limited to 'src/main/model/util/EventLog.java')
-rw-r--r--src/main/model/util/EventLog.java60
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();
+ }
+}