Re: List of files with given extension in a directory

From:
"John B. Matthews" <nospam@nospam.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 21 Aug 2009 11:55:20 -0400
Message-ID:
<nospam-160AB9.11552021082009@news.aioe.org>
In article <1250854031.36@user.newsoffice.de>, Hakan <H.L@softhome.net>
wrote:

[...]

I tried with an alternative version of this code. A special class
implementing Filenamefilter to search for directories, but it does
not work. Can you tell me why? The accept method just gives me false
even for directory files. I quote the code here.

[...]

 static String backsla="\\"; /* Windows systems delimiter*/


Instead of hard-coding the file separator, use the corresponding system
property or static member:

final String fileSep = System.getProperty("file.separator");
final String fileSep = File.separator;

public boolean accept(File dir,String name) {
  String dirpath=dir.getAboslutePath();
  String fpath=dirpath+backsla+name;
  File newfile=new File(fpath);
  return newfile.isDirectory();
}


The result of getAbsolutePath() depends on OS and whether the pathname
is absolute or relative [1]. This works for me:

  public boolean accept(File dir, String name) {
    return new File(dir + File.separator + name).isDirectory();
  }

Alternatively, consider this implementation:

<code>
package cli;

import java.io.File;
import java.io.FilenameFilter;

/** @author John B. Matthews */
public class FilenameFilterTest {

    public static void main(String[] args) {
        File dir = new File(System.getProperty("user.dir"));
        File[] list = dir.listFiles(new DirFilter());
        for (File file : list) {
            System.out.println(file.getName());
        }
    }

    private static class DirFilter implements FilenameFilter {

        public boolean accept(File dir, String name) {
            File[] list = dir.listFiles();
            for (File file : list) {
                if (file.getName().equals(name)) {
                    return file.isDirectory();
                }
            }
            return false;
        }
    }
}
<code>

If this doesn't help, please consider posting a complete example [2].

[1]<http://java.sun.com/javase/6/docs/api/java/io/File.html>
[2]<http://pscode.org/sscce.html>

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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