fix tz as discussed at #51

examples/tz.adoc

@@ -37,21 +37,13 @@ include::tz.java[tags=parameters,indent=0]
 ----
 <.> Time is a timestamp and picocli will automatically convert it to a `LocalTime`.
 <.> For the timezones we need a Custom converter to ensure more short hand ids will work.
-
+<.> Default values for a list of strings are possible using `split=","`
 [source,java]
 ----
 include::tz.java[tags=zoneconverter,indent=0]
 ----
 <.> `SHORT_IDS` here adds more mapping for common timezone shorthand ids. 
 
-Picocli don't have a good way of defining default values for a list thus we 'cheat' by settig values if the list is empty indicating nothing was passed in by the user.
-
-[source,java]
-----
-include::tz.java[tags=defaultzones,indent=0]
-----
-<.> Mapping of a array of strings to ZoneId list using collection stream API.
-
 At the end the final conversion is done and printed out.
 
 [source,java]

examples/tz.java

@@ -1,5 +1,5 @@
 //usr/bin/env jbang "$0" "$@" ; exit $?
-//DEPS info.picocli:picocli:4.2.0 info.picocli:picocli-codegen:4.2.0
+//DEPS info.picocli:picocli:4.2.0 
 
 import picocli.CommandLine;
 import picocli.CommandLine.Command;
@@ -27,8 +27,12 @@ class tz implements Callable<Integer> {
     @Parameters(index = "0", description = "time as hh:mm") 
     private LocalTime time; // <.>
 
-    @Parameters(converter = ZoneIdConverter.class, // <.>
-                description = "List of timezone ids to convert time stamp to")
+    @Parameters(index = "1..*", split = ",",
+    converter = ZoneIdConverter.class, // <.>
+    defaultValue = "America/Los_Angeles,America/Detroit," + // <.>
+            "Europe/London,Europe/Zurich,Asia/Kolkata,Australia/Brisbane",
+    description = "Time zones. Defaults: ${DEFAULT-VALUE}.",
+    hideParamSyntax = true, paramLabel = "[<zones>[,<zones>...]...]")
     List<ZoneId> zones;
     // end::parameters[]
 
@@ -42,19 +46,6 @@ public Integer call() throws Exception { // your business logic goes here...
 
         var t = LocalDateTime.now().with(time);
 
-        // tag::defaultzones[]
-        if(zones.isEmpty()) {
-            zones = Arrays.asList("America/Los_Angeles",
-                    "America/Detroit",
-                    "Europe/London",
-                    "Europe/Zurich",
-                    "Asia/Kolkata",
-                    "Australia/Brisbane").stream()
-                    .map(tz -> ZoneId.of(tz, ZoneId.SHORT_IDS))
-                    .collect(Collectors.toList()); // <.>
-        }
-        // end::defaultzones[]
-
         // tag::conversion[]
         String result = zones.stream().map(zone -> {
             var from = t.atZone(ZoneId.systemDefault());