#152 @command(subcommands) annotation to register subcommands declara…

…tively. Closes #152

RELEASE-NOTES.adoc

@@ -2,6 +2,7 @@
 
 == 0.9.8 - Bugfix and enhancements release for public review. API may change.
 
+* #152 Added support for registering subcommands declaratively with the `@Command(subcommands={...})` annotation. Thanks to https://github.com/nagkumar[nagkumar].
 * #146 Show underlying error when type conversion fails
 * #147 Toggle boolean flags instead of setting to `true`
 * #148 Long string in default value no longer causes infinite loop when printing usage. Thanks to https://github.com/smartboyathome[smartboyathome].

src/main/java/picocli/CommandLine.java

@@ -1247,25 +1247,16 @@ private class Interpreter {
  " is missing the mandatory @Command annotation with a 'name' attribute");
  }
  try {
- Constructor<?> constructor = sub.getConstructor();
- for (Constructor<?> c : sub.getDeclaredConstructors()) {
- if (c.getParameterTypes().length == 0) {
- constructor = c;
- break;
- }
- System.out.println(Arrays.toString(c.getParameterTypes()));
- }
- if (constructor == null) {
- throw new IllegalArgumentException("Could not instantiate subcommand class "
- + sub.getName() + ": missing no-arg constructor.");
- }
+ Constructor<?> constructor = sub.getDeclaredConstructor();
  constructor.setAccessible(true);
- addSubcommand(subCommand.name(), sub.newInstance());
+ commands.put(subCommand.name(), toCommandLine(constructor.newInstance()));
  }
  catch (IllegalArgumentException ex) { throw ex; }
+ catch (NoSuchMethodException ex) { throw new IllegalArgumentException("Cannot instantiate subcommand " +
+ sub.getName() + ": the class has no constructor", ex); }
  catch (Exception ex) {
  throw new IllegalStateException("Could not instantiate and add subcommand " +
- sub.getName() + " with name '" + subCommand.name() + "'", ex);
+ sub.getName() + ": " + ex, ex);
  }
  }
  }

src/test/java/picocli/CommandLineTest.java

@@ -2802,30 +2802,34 @@ class App {
 
  assertEquals(expectedOutput, content);
  }
+ @Command(name = "subsub1")
+ static class SubSub1_testDeclarativelyAddSubcommands {private SubSub1_testDeclarativelyAddSubcommands(){}}
+
+ @Command(name = "sub1", subcommands = {SubSub1_testDeclarativelyAddSubcommands.class})
+ static class Sub1_testDeclarativelyAddSubcommands {public Sub1_testDeclarativelyAddSubcommands(){}}
+
+ @Command(subcommands = {Sub1_testDeclarativelyAddSubcommands.class})
+ static class MainCommand_testDeclarativelyAddSubcommands {}
  @Test
  public void testDeclarativelyAddSubcommands() {
- @Command(name = "subsub1")
- class SubSub1 {private SubSub1(){}}
-
- @Command(name = "sub1", subcommands = {SubSub1.class})
- class Sub1 {public Sub1(){}}
+ CommandLine main = new CommandLine(new MainCommand_testDeclarativelyAddSubcommands());
+ assertEquals(1, main.getSubcommands().size());
 
- @Command(subcommands = {Sub1.class})
- class MainCommand {}
+ CommandLine sub1 = main.getSubcommands().get("sub1");
+ assertEquals(Sub1_testDeclarativelyAddSubcommands.class, sub1.getCommand().getClass());
 
- CommandLine main = new CommandLine(new MainCommand());
- assertEquals(1, main.getSubcommands().size());
- assertEquals(Sub1.class, main.getSubcommands().get("sub1").getCommand().getClass());
+ assertEquals(1, sub1.getSubcommands().size());
+ CommandLine subsub1 = sub1.getSubcommands().get("subsub1");
+ assertEquals(SubSub1_testDeclarativelyAddSubcommands.class, subsub1.getCommand().getClass());
  }
- @Ignore
  @Test
  public void testDeclarativelyAddSubcommandsFailsWithoutNoArgConstructor() {
  @Command(name = "sub1") class ABC {}
  @Command(subcommands = {ABC.class}) class MainCommand {}
  try {
  new CommandLine(new MainCommand());
  } catch (IllegalArgumentException ex) {
- assertEquals("Could not instantiate subcommand class picocli.CommandLineTest$1ABC: missing no-arg constructor.", ex.getMessage());
+ assertEquals("Cannot instantiate subcommand picocli.CommandLineTest$1ABC: the class has no constructor", ex.getMessage());
  }
  }
  @Test