Allow CommandMetadata to be injected into Cli commands

src/main/java/io/airlift/airline/Cli.java

@@ -117,13 +117,21 @@ public C parse(Iterable<String> args)
 
         CommandMetadata command = state.getCommand();
 
+        ImmutableMap.Builder<Class<?>, Object> bindings = ImmutableMap.<Class<?>, Object> builder()
+                .put(GlobalMetadata.class, metadata)
+                .put(CommandMetadata.class, command);
+
+        if (state.getGroup() != null) {
+            bindings.put(CommandGroupMetadata.class, state.getGroup());
+        }
+
         return createInstance(command.getType(),
                 command.getAllOptions(),
                 state.getParsedOptions(),
                 command.getArguments(),
                 state.getParsedArguments(),
                 command.getMetadataInjections(),
-                ImmutableMap.<Class<?>, Object>of(GlobalMetadata.class, metadata));
+                bindings.build());
     }
 
     private void validate(ParseState state)

src/test/java/io/airlift/airline/CommandTest.java

@@ -33,6 +33,8 @@
 import io.airlift.airline.args.ArgsRequired;
 import io.airlift.airline.args.ArgsSingleChar;
 import io.airlift.airline.args.Arity1;
+import io.airlift.airline.args.CommandWithHelp;
+import io.airlift.airline.args.NeedsCommandGroupMetadata;
 import io.airlift.airline.args.OptionsRequired;
 import io.airlift.airline.command.CommandAdd;
 import io.airlift.airline.command.CommandCommit;
@@ -382,4 +384,19 @@ class A
         }
         singleCommandParser(A.class).parse("-lon", "32");
     }
+
+    public void helpOption()
+    {
+        CommandWithHelp command = singleCommandParser(CommandWithHelp.class).parse("CommandWithHelp", "-h");
+        Assert.assertTrue(command.helpOption.showHelpIfRequested());
+    }
+
+    public void injectCommandGroupMetadata()
+    {
+        CliBuilder<NeedsCommandGroupMetadata> builder = Cli.<NeedsCommandGroupMetadata>builder("parser");
+        builder.withGroup("group").withDefaultCommand(NeedsCommandGroupMetadata.class);
+        NeedsCommandGroupMetadata command = builder.build().parse("group");
+        Assert.assertNotNull(command.commandGroupMetadata);
+        Assert.assertEquals(command.commandGroupMetadata.getName(), "group");
+    }
 }

src/test/java/io/airlift/airline/args/CommandWithHelp.java

@@ -0,0 +1,31 @@
+/**
+ * Copyright (C) 2010 the original author or authors.
+ * See the notice.md file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.airlift.airline.args;
+
+import io.airlift.airline.Command;
+import io.airlift.airline.HelpOption;
+
+import javax.inject.Inject;
+
+@Command(name = "CommandWithHelp")
+public class CommandWithHelp
+{
+	@Inject
+	public HelpOption helpOption;
+}

src/test/java/io/airlift/airline/args/NeedsCommandGroupMetadata.java

@@ -0,0 +1,30 @@
+/**
+ * Copyright (C) 2010 the original author or authors.
+ * See the notice.md file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.airlift.airline.args;
+
+import io.airlift.airline.Command;
+import io.airlift.airline.model.CommandGroupMetadata;
+
+import javax.inject.Inject;
+
+@Command(name="NeedsCommandGroupMetadata")
+public class NeedsCommandGroupMetadata
+{
+    @Inject
+    public CommandGroupMetadata commandGroupMetadata;
+}