A nice bit of textbook groovy
Originally published .
Groovy is just so groovy. I’ve been working in Groovy since August of 2007 but I still take such pleasure from little things like this… take some tokens
def tokens = "abc,def foo+bar bar foo"
now break them apart
def parts = tokens.split("[+,\\s]")
now make the array a list…
def list = parts.toList()
now get groovy with the list…
def words = list.unique()
… and check it against test case list …
assert words == ["abc", "def", "foo", "bar"]
… and that just beats the socks off of stuffing the words in a hash then pulling out the keys. Putting it back together I have a single method now:
static parseTags(String tagTokens) {
return tagTokens.split("[+,\\s]").toList().unique()
}
this method will pull apart a string with tagTokens and return a unique list of tags. Inspired by Graeme Rocher’s book “The Definitive Guide to Grails” Listing 9-8. Literally a text book example of why Groovy is so groovy.
Back to our one-liner. I developed the return statement to the method parseTags using a groovy shell script. First, I put groovy in my path by editing my .profile or from the command line…
$ export PATH=$PATH:/path/to/groovy/bin
Once you have that you can run the script from the command line. The whole script reads… (file name: test.groovy)
#!/usr/bin/env groovy
assert "abc,def foo+bar bar foo".split("[+,\\s]").toList().unique() == ["abc", "def", "foo", "bar"]
println "If this prints then it worked." // otherwise the script will bomb out on the previous line
Notice the #! it works because groovy is in our path. Now from the command line I run…
$ groovy test.groovy
… if I chmod the test.groovy file executable it will run as a shell script. And that’s just groovy. I can play with code now changing bits and re-running it over and over finding just the line I need. That little shell script is a test. In a Linux system it’s the lightest test environment imaginable.
And this is a big deal because now I can script Java. I can call Java code from OS commands as easily as I call a shell script. It could mean I could write Java-esque scripting admin files to fire-up Java services like GlassFish or JBoss. That could be very groovy.
These little tweaks can make a huge difference.