Custom Commands

Template commands are subclasses of NotchTemplateCommand. Register a command with NotchTemplateRegistry.addCommand(name, command) and templates can invoke it just like the built-ins.

Anatomy of a command

A command implementation does two things:

1. Decides which template syntax it accepts (a single line, or a block bounded by a matching end).
2. Provides a render hook that runs at output time and writes to the rendering context.

The canonical reference is BasicNotchTemplateCommands.java, which registers all 16 built-in commands.

Registration

registry = new NotchTemplateRegistry(loader)
BasicNotchTemplateCommands.registerAll(registry)
registry.addCommand("upper", new MyUpperCommand())

Templates can then use the new command:

# upper
hello
# end

Renders HELLO.

See also

• Built-in Commands for the 16 shipped commands; useful as a worked example.
• Overview for where commands fit in the broader engine.