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@UnquietCode
Last active July 13, 2018 06:52
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A simple command line utility template for Groovy. Functionality can be implemented by declaring new methods of the form "_doXYZ" where XYZ is the name of the command to run.
/**
* Base class for command line applications.
*
* Children can provide functionality in the form of
* <command name> <arguments...>
*
* @author Ben Fagin
*/
class GroovyCLI implements Runnable {
private String[] args;
// invoked at the command line
GroovyCLI(String[] args) {
this.args = args
}
void run() {
// argument parsing
def newArgs
if (args.length < 1) {
throw new RuntimeException("usage <command name :: 1> <args :: 0+>")
} else if (args.length == 1) {
newArgs = {}
} else {
newArgs = args[1..args.length-1]
}
// make the command name
def cmd = args[0].toLowerCase()
if (cmd.length() > 0) {
def firstChar = Character.toUpperCase(cmd.charAt(0))
firstChar = Character.toString(firstChar)
cmd = firstChar + cmd.substring(1)
}
// run the command
try {
"_do${cmd}"(newArgs)
} catch (MissingMethodException ex) {
throw new RuntimeException("Command '${cmd}' not recognized.")
}
}
}
import groovy.transform.InheritConstructors
/**
* Example application. Pass this as the main class, and Groovy will
* construct the object with the arguments, and then invoke the
* specified command as per the run() method in {@link GroovyCLI}.
*
* @author Ben Fagin
*/
@InheritConstructors
class MyApp extends GroovyCLI {
// a single command called 'test'
// expects any number of arguments
void _doTest(def args) {
println("${args.size()} arguments")
println(args)
}
}
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