How to break execution of method in Groovy? - regex

Question

I have the code below and strange things hapened so I println something. When I passed to method String which matches the regex - printed :
---------->1
---------->2
How is this possible? How to return different return things?
def getInfo(String nameOfFile) {
def matcher = nameOfFile =~ /(\w+)_(\w+)_(\w+)/
if (matcher.matches()) {
matcher.each { fullName, CN, FN, PN->
println "---------->1"
return [nameOfFile, CN, FN, PN]
}
}
println "----------->2"
return [nameOfFile]
}

Answer 1

This just returns from the Closure, not the enclosing method
return [nameOfFile, CN, FN, PN]
Depending on what it is you're trying to do (you don't give any example inputs), you probably want findResult instead of each:
def getInfo( String nameOfFile ) {
def matcher = nameOfFile =~ /(\w+)_(\w+)_(\w+)/
if (matcher.matches()) {
matcher.findResult { fullName, CN, FN, PN->
[nameOfFile, CN, FN, PN]
}
}
else {
[nameOfFile]
}
}

Answer 2

Here is a very crude approximation of the Groovy code in Java (using 1.6):
import java.util.*;
import java.util.regex.*;
interface ClosureBlock {
Object each(String... args);
}
public class Runner {
public List<String> getInfo(String nameOfFile) {
List<String> results = new ArrayList<String>();
Pattern regex = Pattern.compile("(\\w+)_(\\w+)_(\\w+)");
Matcher matcher = regex.matcher(nameOfFile);
if (matcher.matches()) {
String fullName = matcher.group(0);
String CN = matcher.group(1);
String FN = matcher.group(2);
String PN = matcher.group(3);
ClosureBlock closure = new ClosureBlock() {
public Object each(String... args) {
List<String> results = new ArrayList<String>();
String fullName = args[0];
String CN = args[1];
String FN = args[2];
String PN = args[3];
results.add(fullName);
results.add(CN);
results.add(FN);
results.add(PN);
// this return does not exit getInfo()
System.out.println("----------->1");
return results;
}
};
// each returns an Object but we didn't assign it
closure.each(fullName, CN, FN, PN);
}
System.out.println("----------->2");
results.add(nameOfFile);
return results;
}
public static void main(String... args) {
Runner quick = new Runner();
List<String> list = quick.getInfo(args[0]);
System.out.println(list);
}
}
The key points are:
Runner defines an anonymous inner class with an each method. Calling return in the each method does not exit the getInfo method
Even though the each method returns an Object, we don't assign it to anything so the List<String> in getInfo is unaffected.
The Java is ugly and complex. The Groovy code is much more elegant, but regarding your question, the Java code illustrates the idea.