I have to 

concatenate a lot of variables in a script and I want to make it readable, but I failed to separate lines as in java, The following code doesn't compile due to:
Caused by: org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Script1.groovy: 2: unexpected token: << @ line 2, column 1.
   << vars["id2"] << "<id2>"
Code: String
text ="<id>" <<vars["id1"] << "<id><id2>" << vars["id2"] << "<id2>";

Is there a workaround or a better way concatenation a string in groovy?

Related question:

Thank you