Expose some BaseCommand's methods to support generic SSH commands

Exposing getName() to the derived SSH command implementation class allows us to
implement generic SSH commands.

For example Gerrit Shell plugin can now bind multiple commands to the same
class, which retrieves the shell command passed and executes it:

  public class SshShellModule extends PluginCommandModule {
    @Override
    protected void configureCommands() {
      command("ls").to(ShellCommand.class);
      command("ps").to(ShellCommand.class);
      [...]
    }
  }

With the possible implementation:

  public class ShellCommand extends SshCommand {
    @Override
    protected void run() throws UnloggedFailure {
      String cmd = getName().substring(getPluginName().length() + 1);
      ProcessBuilder proc = new ProcessBuilder(cmd);
      Process cmd = proc.start();
      [...]
    }
  }

And the call:

  davido@wizball:>ssh gerrit shell ls
  davido@wizball:>ssh gerrit shell ps

Change-Id: I43be66a99340e839b70c07e93752278cee5f039d

Documentation/dev-plugins.txt

@@ -403,6 +403,44 @@ by PrintHello class will be available to users as:
 $ ssh -p 29418 review.example.com helloworld print
 ----
 
+Multiple SSH commands can be bound to the same implementation class. For
+example a Gerrit Shell plugin can bind different shell commands to the same
+implementation class:
+
+[source,java]
+----
+public class SshShellModule extends PluginCommandModule {
+  @Override
+  protected void configureCommands() {
+    command("ls").to(ShellCommand.class);
+    command("ps").to(ShellCommand.class);
+    [...]
+  }
+}
+----
+
+With the possible implementation:
+
+[source,java]
+----
+public class ShellCommand extends SshCommand {
+  @Override
+  protected void run() throws UnloggedFailure {
+    String cmd = getName().substring(getPluginName().length() + 1);
+    ProcessBuilder proc = new ProcessBuilder(cmd);
+    Process cmd = proc.start();
+    [...]
+  }
+}
+----
+
+And the call:
+
+----
+$ ssh -p 29418 review.example.com shell ls
+$ ssh -p 29418 review.example.com shell ps
+----
+
 [[configuration]]
 Configuration
 -------------

gerrit-sshd/src/main/java/com/google/gerrit/sshd/BaseCommand.java

@@ -127,11 +127,11 @@ public abstract class BaseCommand implements Command {
   }
 
   @Nullable
-  String getPluginName() {
+  protected String getPluginName() {
     return pluginName;
   }
 
-  String getName() {
+  protected String getName() {
     return commandName;
   }
 
@@ -139,7 +139,7 @@ public abstract class BaseCommand implements Command {
     this.commandName = prefix;
   }
 
-  String[] getArguments() {
+  public String[] getArguments() {
     return argv;
   }