The document shows examples of using switch statements in Groovy with different data types and cases. It demonstrates matching strings, regular expressions, ranges, collections, objects, null values, and using a closure as a case.

3. $ time groovy -e 'println "Hello, world!";'
Hello, world!
real 0m1.177s
user 0m1.321s
sys 0m0.171s
$ time groovyclient -e 'println "Hello,
world!";'
Hello, world!
real 0m0.029s
user 0m0.001s
sys 0m0.002s

7. String s = ...
switch (s) {
case "quux":
processQuux(s);
// fall-through
case "foo":
case "bar":
processFooOrBar(s);
break;
case "baz":
processBaz(s);
// fall-through
default:
processDefault(s);
break;
}

8. import java.util.regex.Matcher
Object x = ...
switch (x) {
case "abc": // x "abc"
break
case ~/a(.*)c/: // x
assert Matcher.lastMatcher[0][0] == "abbc"
assert Matcher.lastMatcher[0][1] == "bb"
break
case 1..3: // x 1 3
break
case [1,3,5]: // x 1,3,5
break
// ....
}

9. switch (x) {
// ....
case String: // x String
break
case {it % 2 == 0}: // x
break
case null: // x null
break
case a: // a
// a.isCase(x) true
break
}

11. double highestScore = students
.filter(#{ s -> s.gradYear == 2010 })
.map( #{ s -> s.score })
.max();

12. def highestScore = students.
findAll({ s -> s.gradYear == 2010 }).
collect({ s -> s.score }).
max()

14. InputStream in = null;
OutputStream out = null;
try {
in = new FileInputStream(“src”);
out = new FileOutputStream(“dst”);
byte[] buf = new byte[8192];
int n = 0;
while((n = in.read(buf)) >= 0) { out.write(buf, 0, n); }
} catch (IOException e) {
//
} finally {
if (in != null) {
try { in.close(); } catch (IOException e) { }
}
if (out != null) {
try { out.close(); } catch (IOException e) { }
}
}

15. try (InputStream in = new FileInputStream(“src”);
OutputStream out = new FileOutputStream(“dst”)) {
byte[] buf = new byte[8192];
int n = 0;
while((n = in.read(buf)) >= 0) {
out.write(buf, 0, n);
}
}

16. new File(“dest”).withOutputStream { out ->
new File(“src”).withInputStream { ins ->
byte[] buf = new byte[8192]
int n = 0
while((n = ins.read(buf)) >= 0) {
out.write(buf, 0, n);
}
}
}
new File("dest") << new File("src").bytes

18. Map<String, Map<String, List<Employee>>> map
= new HashMap<String, Map<String, List<Employee>>>();
Map<String, Map<String, List<Employee>>> map = new HashMap<>();

19. Map<String, Map<String, List<Employee>>> map = [:]
map.put(1, “A”) //
map.put(“HOGE”, new Date()) //

21. import java.util.concurrent.*;
public class Fibonacci extends RecursiveTask<Integer> {
final int n;
public Fibonacci(int n) { this.n = n; }
public Integer compute() {
if (n <= 1)
return n;
Fibonacci f1 = new Fibonacci(n - 1);
f1.fork();
Fibonacci f2 = new Fibonacci(n - 2);
return f2.compute() + f1.join();
}
}

22. import static groovyx.gpars.GParsPool.*
def fibo(num) {
withPool {
runForkJoin(num) { n ->
switch (n) {
case 0..1:
return n
default:
forkOffChild(n - 1)
forkOffChild(n - 2)
childrenResults.sum()
}
}
}
}
assert fibo(10) == 55
assert fibo(20) == 6765