Version 1, September 2006

[GpsPrune.git] / tim / prune / data / Timestamp.java

diff --git a/tim/prune/data/Timestamp.java b/tim/prune/data/Timestamp.java
new file mode 100644 (file)
index 0000000..965853a
--- /dev/null
+++ b/tim/prune/data/Timestamp.java
@@ -0,0 +1,150 @@
+package tim.prune.data;
+
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Calendar;
+import java.util.Date;
+
+/**
+ * Class to hold the timestamp of a track point
+ * and provide conversion functions
+ */
+public class Timestamp
+{
+       private boolean _valid = false;
+       private long _seconds = 0L;
+       private String _text = null;
+
+       private static DateFormat DEFAULT_DATE_FORMAT = DateFormat.getDateTimeInstance();
+       private static DateFormat[] ALL_DATE_FORMATS = null;
+       private static Calendar CALENDAR = null;
+       private static long SECS_SINCE_1970 = 0L;
+       private static long SECS_SINCE_GARTRIP = 0L;
+       private static long MSECS_SINCE_1970 = 0L;
+       private static long MSECS_SINCE_1990 = 0L;
+       private static long TWENTY_YEARS_IN_SECS = 0L;
+
+       private static final long GARTRIP_OFFSET = 631065600L;
+
+       // Static block to initialise offsets
+       static
+       {
+               CALENDAR = Calendar.getInstance();
+               MSECS_SINCE_1970 = CALENDAR.getTimeInMillis();
+               SECS_SINCE_1970 = MSECS_SINCE_1970 / 1000L;
+               SECS_SINCE_GARTRIP = SECS_SINCE_1970 - GARTRIP_OFFSET;
+               CALENDAR.add(Calendar.YEAR, -20);
+               MSECS_SINCE_1990 = CALENDAR.getTimeInMillis();
+               TWENTY_YEARS_IN_SECS = (MSECS_SINCE_1970 - MSECS_SINCE_1990) / 1000L;
+               // Date formats
+               ALL_DATE_FORMATS = new DateFormat[] {
+                       DEFAULT_DATE_FORMAT,
+                       new SimpleDateFormat("EEE MMM dd HH:mm:ss yyyy"),
+                       new SimpleDateFormat("HH:mm:ss dd MMM yyyy"),
+                       new SimpleDateFormat("dd MMM yyyy HH:mm:ss"),
+                       new SimpleDateFormat("yyyy MMM dd HH:mm:ss")
+               };
+       }
+
+
+       /**
+        * Constructor
+        */
+       public Timestamp(String inString)
+       {
+               if (inString != null && !inString.equals(""))
+               {
+                       // Try to parse into a long
+                       try
+                       {
+                               long rawValue = Long.parseLong(inString.trim());
+                               // check for each format possibility and pick nearest
+                               long diff1 = Math.abs(SECS_SINCE_1970 - rawValue);
+                               long diff2 = Math.abs(MSECS_SINCE_1970 - rawValue);
+                               long diff3 = Math.abs(MSECS_SINCE_1990 - rawValue);
+                               long diff4 = Math.abs(SECS_SINCE_GARTRIP - rawValue);
+
+                               // Start off with "seconds since 1970" format
+                               long smallestDiff = diff1;
+                               _seconds = rawValue;
+                               // Now check millis since 1970
+                               if (diff2 < smallestDiff)
+                               {
+                                       // milliseconds since 1970
+                                       _seconds = rawValue / 1000L;
+                                       smallestDiff = diff2;
+                               }
+                               // Now millis since 1990
+                               if (diff3 < smallestDiff)
+                               {
+                                       // milliseconds since 1990
+                                       _seconds = rawValue / 1000L + TWENTY_YEARS_IN_SECS;
+                                       smallestDiff = diff3;
+                               }
+                               // Lastly, check garmin offset
+                               if (diff4 < smallestDiff)
+                               {
+                                       // milliseconds since garmin offset
+                                       _seconds = rawValue + GARTRIP_OFFSET;
+                               }
+                               _valid = true;
+                       }
+                       catch (NumberFormatException nfe)
+                       {
+                               // String is not a long, so try a date/time string instead
+                               // try each of the date formatters in turn
+                               Date date = null;
+                               for (int i=0; i<ALL_DATE_FORMATS.length && !_valid; i++)
+                               {
+                                       try
+                                       {
+                                               date = ALL_DATE_FORMATS[i].parse(inString);
+                                               CALENDAR.setTime(date);
+                                               _seconds = CALENDAR.getTimeInMillis() / 1000L;
+                                               _valid = true;
+                                       }
+                                       catch (ParseException e) {}
+                               }
+                       }
+               }
+       }
+
+
+       /**
+        * @return true if timestamp is valid
+        */
+       public boolean isValid()
+       {
+               return _valid;
+       }
+
+
+       /**
+        * Calculate the difference between two Timestamps in seconds
+        * @param inOther other, earlier Timestamp
+        * @return number of seconds since other timestamp
+        */
+       public long getSecondsSince(Timestamp inOther)
+       {
+               return _seconds - inOther._seconds;
+       }
+
+
+       /**
+        * @return Description of timestamp in locale-specific format
+        */
+       public String getText()
+       {
+               if (_text == null)
+               {
+                       if (_valid)
+                       {
+                               CALENDAR.setTimeInMillis(_seconds * 1000L);
+                               _text = DEFAULT_DATE_FORMAT.format(CALENDAR.getTime());
+                       }
+                       else _text = "";
+               }
+               return _text;
+       }
+}