Allow for redundant timezone name and timezone offset. Although, not …

…ISO 8601 compliant, Java allows it:

ISO_ZONED_DATE_TIME
public static final DateTimeFormatter ISO_ZONED_DATE_TIME
The ISO-like date-time formatter that formats or parses a date-time with offset and zone, such as '2011-12-03T10:15:30+01:00[Europe/Paris]'.
This returns an immutable formatter capable of formatting and parsing a format that extends the ISO-8601 extended offset date-time format to add the time-zone. The section in square brackets is not part of the ISO-8601 standard. The format consists of:

The ISO_OFFSET_DATE_TIME
If the zone ID is not available or is a ZoneOffset then the format is complete.
An open square bracket '['.
The zone ID. This is not part of the ISO-8601 standard. Parsing is case sensitive.
A close square bracket ']'.
The returned formatter has a chronology of ISO set to ensure dates in other calendar systems are correctly converted. It has no override zone and uses the STRICT resolver style.

src/main/java/com/cedarsoftware/util/DateUtilities.java

@@ -112,7 +112,7 @@ public final class DateUtilities {
             Pattern.CASE_INSENSITIVE);
 
     private static final Pattern timePattern = Pattern.compile(
-            "(" + d2 + "):(" + d2 + ")(?::(" + d2 + ")(" + nano + ")?)?(" + tz_Hh_MM + "|" + tz_HHMM + "|" + tz_Hh + "|Z|" + tzNamed + ")?",
+            "(" + d2 + "):(" + d2 + ")(?::(" + d2 + ")(" + nano + ")?)?(" + tz_Hh_MM + "|" + tz_HHMM + "|" + tz_Hh + "|Z)?(" + tzNamed + ")?",
             Pattern.CASE_INSENSITIVE);
 
     private static final Pattern dayPattern = Pattern.compile("\\b(" + days + ")\\b", Pattern.CASE_INSENSITIVE);
@@ -150,9 +150,9 @@ private DateUtilities() {
     }
 
     /**
-     * Original API. If the date-time given does not include a timezone offset, then ZoneId.systemDefault() will be used.
-     * We recommend using the parseDate(3 args) version, so you can control the default timezone used when one is not
-     * specified.
+     * Original API. If the date-time given does not include a timezone offset or name, then ZoneId.systemDefault()
+     * will be used. We recommend using the parseDate(3 args) version, so you can control the default timezone used
+     * when one is not specified.
      * @param dateStr String containing a date.  If there is excess content, it will throw an IllegalArgumentException.
      * @return Date instance that represents the passed in date.  See comments at top of class for supported
      * formats.  This API is intended to be super flexible in terms of what it can parse.  If a null or empty String is
@@ -185,7 +185,7 @@ public static ZonedDateTime parseDate(String dateStr, ZoneId defaultZoneId, bool
         dateStr = dateStr.trim();
 
         if (allDigits.matcher(dateStr).matches()) {
-            return Instant.ofEpochMilli(Long.parseLong(dateStr)).atZone(defaultZoneId);
+            return Instant.ofEpochMilli(Long.parseLong(dateStr)).atZone(ZoneId.of("UTC"));
         }
 
         String year, day, remains, tz = null;
@@ -246,7 +246,6 @@ public static ZonedDateTime parseDate(String dateStr, ZoneId defaultZoneId, bool
         remains = remains.trim();
         matcher = timePattern.matcher(remains);
         remnant = matcher.replaceFirst("");
-        boolean noTime = false;
 
         if (remnant.length() < remains.length()) {
             hour = matcher.group(1);
@@ -258,7 +257,12 @@ public static ZonedDateTime parseDate(String dateStr, ZoneId defaultZoneId, bool
                 fracSec = "0" + matcher.group(4);
             }
             if (matcher.group(5) != null) {
-                tz = stripBrackets(matcher.group(5).trim());
+                tz = matcher.group(5).trim();
+            }
+            if (matcher.group(6) != null) {
+                if (StringUtilities.isEmpty(tz)) {    // Only use timezone name when offset is not used
+                    tz = stripBrackets(matcher.group(6).trim());
+                }
             }
         }
 

src/test/java/com/cedarsoftware/util/TestDateUtilities.java

@@ -870,7 +870,7 @@ void testTimeBetterThanMilliResolution()
         assertEquals(-60*60*5, zonedDateTime.getOffset().getTotalSeconds());
     }
 
-    private static Stream provideBadFormats() {
+    private static Stream provideRedundantFormats() {
         return Stream.of(
                 Arguments.of("2024-01-19T12:00:00-08:00[America/Los_Angeles]"),
                 Arguments.of("2024-01-19T22:30:00+01:00[Europe/Paris]"),
@@ -890,14 +890,11 @@ private static Stream provideBadFormats() {
                 Arguments.of("2024-01-19T22:30:00+01:00 Europe/Paris"),
                 Arguments.of("2024-01-19T23:59:59Z UTC"),
                 Arguments.of("2024-01-19T23:59:59Z[UTC]"),
-                Arguments.of("2024-01-19T07:30:01[UTC] America/New_York"),
                 Arguments.of("2024-01-19T07:30:01.123+0100GMT"),
                 Arguments.of("2024-01-19T07:30:01.123+0100[GMT]"),
                 Arguments.of("2024-01-19T07:30:01.123+0100 GMT"),
                 Arguments.of("2024-01-19T07:30:01.123+0100 [GMT]"),
                 Arguments.of("2024-01-19T07:30:01.123-1000GMT"),
-                Arguments.of("2024-01-19T07:30:01.123-1000[GMT ]"),
-                Arguments.of("2024-01-19T07:30:01.123-1000[ GMT ]"),
                 Arguments.of("2024-01-19T07:30:01.123-1000 GMT"),
                 Arguments.of("2024-01-19T07:30:01.123-1000 [GMT]"),
                 Arguments.of("2024-01-19T07:30:01.123+2 GMT"),
@@ -929,20 +926,14 @@ private static Stream provideBadFormats() {
                 Arguments.of("07:30:01.123-11:00 [EST] January 21, 2024, Sunday"),
                 Arguments.of("07:30:01.123-11:00 [America/New_York] January 21, 2024, Sunday"),
                 Arguments.of("07:30:01.123-11:00 [Africa/Cairo] 21 Jan 2024 Sun"),
-                Arguments.of("07:30:01.123-11:00 [Africa/Cairo] 2024 Jan 21st Sat"),
-                Arguments.of("12.17.1965 07:05:"),
-                Arguments.of("12.17.1965 07:05:.123"),
-                Arguments.of("12.17.1965 07:05.123"),
-                Arguments.of("12.17.1965 07:05.12-0500")
+                Arguments.of("07:30:01.123-11:00 [Africa/Cairo] 2024 Jan 21st Sat")
                 );
     }
 
     @ParameterizedTest
-    @MethodSource("provideBadFormats")
+    @MethodSource("provideRedundantFormats")
     void testFormatsThatShouldNotWork(String badFormat)
     {
-        assertThatThrownBy(() -> DateUtilities.parseDate(badFormat, ZoneId.systemDefault(), true))
-                .isInstanceOf(java.lang.IllegalArgumentException.class)
-                .hasMessageContaining("Issue parsing date-time, other characters present:");
+        DateUtilities.parseDate(badFormat, ZoneId.systemDefault(), true);
     }
 }