Package software.amazon.smithy.cli

Class Cli

  • public final class Cli
extends java.lang.Object
    This class provides a very basic CLI abstraction.

    Note: The argument parser does not support setting an argument using foo=bar.

    The following options are automatically added to each command:

    • --help | -h: Prints subcommand help text.
    • --debug: Prints debug information, including exception stack traces.
    • --no-color: Explicitly disables ANSI colors.
    • --force-color: Explicitly enables ANSI colors.
    • --stacktrace: Prints the stacktrace of any CLI exception that is thrown.
    • --logging: Sets the log level to one of OFF, SEVERE, WARNING, INFO, FINE, ALL.

    Why are we not using a library for this? Because parsing command line options isn't difficult, we don't need to take a dependency, this code uses no reflection to improve startup time. We can control exactly what CLI features are supported in case we want to migrate to a library or event a different language.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static java.lang.String DEBUG  
      static java.lang.String FORCE_COLOR  
      static java.lang.String HELP  
      static java.lang.String LOGGING  
      static java.lang.String NO_COLOR  
      static java.lang.String STACKTRACE  

    • Constructor Summary

      Constructors 
      Constructor Description
      Cli​(java.lang.String applicationName)
      Creates a new CLI with the given name.
      Cli​(java.lang.String applicationName, java.lang.ClassLoader classLoader)
      Creates a new CLI with the given name.

    • Method Summary

      Modifier and Type Method Description
      void addCommand​(Command command)
      Adds a subcommand to the CLI.
      static java.util.function.Consumer<java.lang.String> getStderr()
      Gets the stderr consumer.
      static java.util.function.Consumer<java.lang.String> getStdout()
      Gets the stdout consumer.
      void run​(java.lang.String[] args)
      Execute the command line using the given arguments.
      static void setStderr​(java.util.function.Consumer<java.lang.String> printer)
      Configures a custom STDERR printer.
      static void setStdout​(java.util.function.Consumer<java.lang.String> printer)
      Configures a custom STDOUT printer.
      static void setUseAnsiColors​(boolean useAnsiColors)
      Explicitly configures whether or not to use ANSI colors.
      static void stderr​(java.lang.Object message)
      Write a line of text to the configured STDERR.
      static void stdout​(java.lang.Object message)
      Write a line of text to the configured STDOUT.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • Cli

        public Cli​(java.lang.String applicationName)
        Creates a new CLI with the given name.
        Parameters:
        applicationName - Name of the CLI application.

      • Cli

        public Cli​(java.lang.String applicationName,
           java.lang.ClassLoader classLoader)
        Creates a new CLI with the given name.
        Parameters:
        applicationName - Name of the CLI application.
        classLoader - ClassLoader to use when invoking commands.

    • Method Detail

      • addCommand

        public void addCommand​(Command command)
        Adds a subcommand to the CLI.
        Parameters:
        command - Command to add.

      • run

        public void run​(java.lang.String[] args)
        Execute the command line using the given arguments.
        Parameters:
        args - Arguments to parse.

      • setStdout

        public static void setStdout​(java.util.function.Consumer<java.lang.String> printer)
        Configures a custom STDOUT printer.
        Parameters:
        printer - Consumer responsible for writing to STDOUT.

      • setStderr

        public static void setStderr​(java.util.function.Consumer<java.lang.String> printer)
        Configures a custom STDERR printer.
        Parameters:
        printer - Consumer responsible for writing to STDERR.

      • getStdout

        public static java.util.function.Consumer<java.lang.String> getStdout()
        Gets the stdout consumer.
        Returns:
        Returns the stdout consumer.

      • getStderr

        public static java.util.function.Consumer<java.lang.String> getStderr()
        Gets the stderr consumer.
        Returns:
        Returns the stderr consumer.

      • stdout

        public static void stdout​(java.lang.Object message)
        Write a line of text to the configured STDOUT.
        Parameters:
        message - Message to write.

      • stderr

        public static void stderr​(java.lang.Object message)
        Write a line of text to the configured STDERR.
        Parameters:
        message - Message to write.

      • setUseAnsiColors

        public static void setUseAnsiColors​(boolean useAnsiColors)
        Explicitly configures whether or not to use ANSI colors.
        Parameters:
        useAnsiColors - Set to true or false to enable/disable.