java.util.Enumeration in Scala

Question

How do I properly call exists for java.util.Enumeration? I cannot change the source, it's from HttpServletRequest.

This (unrelated) code works:

val a = List("One", "Two", "Three")
a exists (_ contains "T")

But why this code cannot be compiled:

import collection.JavaConversions.enumerationAsScalaIterator
enumerationAsScalaIterator(req.getHeaderNames[String])[String] exists (_ contains "T")

I'm using IntelliJ as my IDE. The above code doesn't show any error in the editor but will throw error when compiled:

error: ';' expected but '[' found. enumerationAsScalaIterator(req.getHeaderNames[String])[String] exists (_ contains "T")

Pablo Fernandez · Accepted Answer · 2011-11-03 17:35:10Z

5

Try

import collection.JavaConversions.enumerationAsScalaIterator

req.getHeaderNames() exists (_ contains "T")

edited Nov 3, 2011 at 17:35

answered Nov 3, 2011 at 17:23

Pablo Fernandez

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Comments

Adam Rabung · Accepted Answer · 2011-11-03 17:26:33Z

1

Your second [String] here: req.getHeaderNames[String])[String] Isn't needed, and isn't valid Scala. Try

enumerationAsScalaIterator(req.getHeaderNames[String]) exists (_ contains "T")

Better yet, enumerationAsScalaIterator is available implicitly, so you should be able to just do:

req.getHeaderNames exists (_ contains "T")

answered Nov 3, 2011 at 17:26

Adam Rabung

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1 Comment

wiradikusuma Over a year ago

Same with above, it produces "Cannot resolve symbol contains" in the IDE.

Community · Accepted Answer · 2017-05-23 11:52:47Z

1

It should be enumerationAsScalaIterator[String](req.getHeaderNames[String]) exists (_ contains "T") (or use it implicitly, as Pablo Fernandez suggests). No idea why it wouldn't show an error in the editor, however.

edited May 23, 2017 at 11:52

CommunityBot

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answered Nov 3, 2011 at 17:25

Alexey Romanov

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Comments

wiradikusuma · Accepted Answer · 2011-11-04 15:48:34Z

1

Looks like the only way to do it for HttpServletRequest.getHeaderNames is the good old loop:

val headers = req.getHeaderNames
while (headers.hasMoreElements) {
if (headers.nextElement.asInstanceOf[String] contains "T")
  return FOO
}

answered Nov 4, 2011 at 15:48

wiradikusuma

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