From f1348ede80842717e235c85f2efba77ff74663db Mon Sep 17 00:00:00 2001
From: "J.A. de Jong - Redu-Sone B.V., ASCEE V.O.F" <j.a.dejong@ascee.nl>
Date: Mon, 3 Apr 2023 13:16:39 +0200
Subject: [PATCH] Cached time string of measurement time stamp

---
 src/lasp/lasp_measurement.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/lasp/lasp_measurement.py b/src/lasp/lasp_measurement.py
index 8d2a012..924d466 100644
--- a/src/lasp/lasp_measurement.py
+++ b/src/lasp/lasp_measurement.py
@@ -52,6 +52,7 @@ import os, time, wave, logging
 from .lasp_common import SIQtys, Qty, getFreq
 from .lasp_cpp import Window, DaqChannel, LASP_VERSION_MAJOR, AvPowerSpectra
 from typing import List
+from functools import lru_cache
 
 
 def getSampWidth(dtype):
@@ -248,6 +249,9 @@ class Measurement:
             except KeyError:
                 self._sens = np.ones(self.nchannels)
 
+            # The time is cached AND ALWAYS ASSUMED TO BE AN IMMUTABLE OBJECT.
+            # It is also cached. Changing the measurement timestamp should not
+            # be done.
             self._time = f.attrs['time']
 
             # Quantity stored as channel.
@@ -375,6 +379,7 @@ class Measurement:
             self._comment = cmt
 
     @property
+    @lru_cache()
     def recTime(self):
         """Returns the total recording time of the measurement, in float
         seconds."""
@@ -385,6 +390,19 @@ class Measurement:
         """Returns the measurement time in seconds since the epoch."""
         return self._time
 
+    @property
+    @lru_cache()
+    def timestr(self):
+        """
+        Return a properly formatted string of the measurement time, in order of
+    
+        year-month-day hour etc.
+
+        """
+        time_struct = time.localtime(self.time)
+        time_string = time.strftime('%Y-%m-%d %H:%M:%S', time_struct)
+        return time_string
+
     def rms(self, channels=None, substract_average=False):
         """Returns the root mean square values for each channel