gh-52 add mention of default val to oscTempFractionDigits user guide entry, change warning about bad value to an exception

Author: John Lage

docs/MMTC_Users_Guide.adoc

@@ -1372,6 +1372,7 @@ Always set this value to false if using the AMPCS telemetry source plugin’s Am
 |OPTIONAL
 |INT
 |The maximum number of fractional/decimal digits to which the oscillator temperature is to be written in the Time History File before rounding takes place.
+Defaults to 9 digits if key isn't included in config or if the value provided can't be parsed.
 
 |product.sclkScetFile.create
 |REQUIRED

mmtc-core/src/main/java/edu/jhuapl/sd/sig/mmtc/cfg/MmtcConfig.java

@@ -901,7 +901,7 @@ public Integer getSclkScetApplicableDurationDays() {
      * time history file
      * @return the integer specified in the config unless key isn't present or can't be parsed, then return safe default
      */
-    public int getOscTempFractionDigits() {
+    public int getOscTempFractionDigits() throws MmtcException {
         final String keyName = "table.timeHistoryFile.oscTempFractionDigits";
         int numDigits = 9;
 
@@ -912,7 +912,7 @@ public int getOscTempFractionDigits() {
                 logger.debug("Key {} not found in TimeCorrelationConfigProperties: defaulting to value {}", keyName, numDigits);
             }
         } catch (Exception e) {
-            logger.warn("Failed to parse integer provided in key {}, defaulting to {}", keyName, numDigits);
+            throw new MmtcException(String.format("Failed to parse value provided in config key %s, ensure it's a valid integer.", keyName), e);
         }
         return numDigits;
     }