Move trigger time file reader to separate class and convert to Java 8 time instead...

diff --git a/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/io/TriggerTimesFileReader.java b/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/io/TriggerTimesFileReader.java
new file mode 100644 (file)
index 0000000..592bcd7
--- /dev/null
+++ b/Code/Projects/SmartPlugDetector/src/main/java/edu/uci/iotproject/io/TriggerTimesFileReader.java
@@ -0,0 +1,68 @@
+package edu.uci.iotproject.io;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.*;
+
+/**
+ * Parses a file to obtain the timestamps at which the smart plug was toggled on/off.
+ *
+ * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
+ * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
+ */
+public class TriggerTimesFileReader {
+
+    public static final ZoneId ZONE_ID_LOS_ANGELES = ZoneId.of("America/Los_Angeles");
+    public static final ZoneId ZONE_ID_BUDAPEST = ZoneId.of("Europe/Budapest");
+
+    /**
+     * Reads a file with trigger timestamps and parses the timestamps into {@link Instant}s using the rules specified
+     * by {@link #parseTriggerTimestamp(String, boolean)}.
+     * @param fileName The absolute path to the file with trigger timestamps.
+     * @param _24hFormat {@code true} if the timestamps in the file are in 24 hour format, {@code false} if they are in
+     *                               AM/PM format.
+     * @return A containing the trigger timestamps represented as {@code Instant}s.
+     */
+    public List<Instant> readTriggerTimes(String fileName, boolean _24hFormat) {
+        List<Instant> listTriggerTimes = new ArrayList<>();
+        try {
+            File file = new File(fileName);
+            BufferedReader br = new BufferedReader(new FileReader(file));
+            String s;
+            while ((s = br.readLine()) != null) {
+                listTriggerTimes.add(parseTriggerTimestamp(s, _24hFormat));
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        System.out.println("List has: " + listTriggerTimes.size());
+        return listTriggerTimes;
+    }
+
+    /**
+     * Parses a timestamp string to an {@link Instant} (UTC). Assumes timestamps are LA time.
+     * Format is expected to be either "uuuu-MM-dd HH:mm:ss" or "uuuu-MM-dd h:mm:ss a".
+     *
+     * @param timestampStr The string containing a date-time timestamp for LA's timezone.
+     * @param _24hFormat {@code true} if the time in {@code timestampStr} is given in 24 hour format, {@code false} if
+     *                               it is given in AM/PM format.
+     * @return An {@code Instant} representation of the parsed timestamp. Note that the {@code Instant} marks a point on
+     *         the timeline in UTC. Use {@link Instant#atZone(ZoneId)} to convert to the corresponding time in a given
+     *         timezone.
+     */
+    public Instant parseTriggerTimestamp(String timestampStr, boolean _24hFormat) {
+        // Note: only one 'h' when not prefixed with leading 0 for 1-9; and only one 'a' for AM/PM marker in Java 8 time
+        String format = _24hFormat ? "uuuu-MM-dd HH:mm:ss" : "uuuu-MM-dd h:mm:ss a";
+        LocalDateTime localDateTime = LocalDateTime.parse(timestampStr, DateTimeFormatter.ofPattern(format, Locale.US));
+        ZonedDateTime laZonedDateTime = localDateTime.atZone(ZONE_ID_LOS_ANGELES);
+        return laZonedDateTime.toInstant();
+    }
+
+}