Daily scala

Calling Java APIs from Scala is completely seamless. I will demonstrate this functionality by copying data from a URL to a file and then making a copy of that file.

Important Note: Scala 2.8 is getting a redesigned API for accessing files and streams based on JSR-203 New NIO. It is quite nice to use. For example File("/tmp") / "dir" / "dir2" will create a file to /\
tmp/dir/dir2. That is just the most basic of what you can expect. I will do a couple topics on that when it gets closer to being finalized.

1. scala> import java.net._
2. import java.net._
3. scala> import scala.io._
4. import scala.io._
5. scala> import java.io.{File, FileWriter}
6. import java.io.{File, FileWriter}
7. scala> val in = Source.fromURL("http://www.google.com")
8. in: scala.io.Source = non-empty iterator
9. scala> // Until scala 2.8 we have to use the standard java streams and idioms
10. scala> val out = new FileWriter("/tmp/daily-scala")
11. out: java.io.FileWriter = java.io.FileWriter@71d0e17a
12. scala> try {
13.     | out.write( in.getLines.mkString("\n") )
14.     | }finally{
15.     | out.close
16.     | }
17. scala> // now lets copy the file
18. scala> val copy = new FileWriter("/tmp/copy")
19. copy: java.io.FileWriter = java.io.FileWriter@7bfd25ce
20. scala> try {
21.     | copy.write( Source.fromFile("/tmp/daily-scala").getLines.mkString("\n") )
22.     | } finally {copy.close}
23. scala> val copy2 = new FileWriter("/tmp/copy2")
24. copy2: java.io.FileWriter = java.io.FileWriter@7bfd25ce
25. // You can reuse a source if you reset it
26. scala> try {
27.     | copy2.write( in.reset.getLines.mkString("\n") )
28.     | } finally {copy2.close}
29. // Change all 'e' to upper case.  We could write this to a file if we desired
30. scala> in.reset.getLines.mkString("\n").map( c => if (c == 'e') c.toUpperCase else c).mkString("")
31. res9: String = This is thE dEmo filE