CODEWITHSUNDEEP
javafiledirectory
Alexandre Loctin
Alexandre Loctin

Reputation: 129

Getting files by lastmodified date

What is the fastest way to get files by lastmodified date? I got a directory with some txt files. User can do a research by date, I list all files in the directory by lastmodified date (in File[]) and i search for the right file with the specific date. I use a collection sort using lastmodified date to sort my files. When I get files from my local drive it's fast but when i want to access to a drive on the netword (private network) it can take about 10 minutes to get a file. I know i can't be quicker than the network but is there a solution that can be really faster than my solution?

exemple for my code :

File[] files = repertoire.listFiles();         

Arrays.sort(files, new Comparator<File>() {
    @Override
    public int compare(File o1, File o2) {
        return Long.valueOf(o2.lastModified()).compareTo(o1.lastModified());
    }
});

for (File element : files) {
    // i get the right file;
}

Thanks for your help

Here is the solution : 

Path repertoiry = Paths.get(repertoire.getAbsolutePath());
final DirectoryStream<Path> stream = Files.newDirectoryStream(repertoiry, new DirectoryStream.Filter<Path>() {
     @Override
     public boolean accept(Path entry) throws IOException {
          return Files.getLastModifiedTime(entry, LinkOption.NOFOLLOW_LINKS).toMillis() >= (dateRechercheeA.getTime() - (24 * 60 * 60 * 1000)) && Files.getLastModifiedTime(entry, LinkOption.NOFOLLOW_LINKS).toMillis() <= (dateRechercheeB.getTime() + (24 * 60 * 60 * 1000));
     }
});
for (Path path : stream) {
     if (!path.toFile().getName().endsWith("TAM") && !path.toFile().getName().endsWith("RAM")) {
         listFichiers.add(path.toFile());
     }
}

Upvotes: 5

Views: 2627

Answers (1)

DMEx38
DMEx38

Reputation: 156

With java 7 NIO package it's possible to filter a directory to list only files wanted.
(Warning DirectoryStreams do not iterate through subdirectories.)

Path repertoire = Paths.get("[repertoire]");
try ( DirectoryStream<Path> stream = Files.newDirectoryStream(repertoire, new DirectoryStream.Filter<Path>() {
        @Override
        public boolean accept(Path entry) throws IOException {
            return Files.getLastModifiedTime(entry, LinkOption.NOFOLLOW_LINKS).toMillis() = [DATE_SEARCHED (long)] 
        }
 })){

     for (Path path : stream) {
          // Path filtered...
     }
 }

Normally this solution provide better performance than create a full list of file, sort the list and after that iterate over the list to find the right date.

With your code :

//use final keyword to permit access in the filter.
final Date dateRechercheeA = new Date();
final Date dateRechercheeB = new Date();

Path repertoire = Paths.get("[repertoire]");
try (DirectoryStream<Path> stream = Files.newDirectoryStream(repertoire, new DirectoryStream.Filter<Path>() {
    @Override
    public boolean accept(Path entry) throws IOException {
        long entryDateDays = Files.getLastModifiedTime(entry, LinkOption.NOFOLLOW_LINKS).to(TimeUnit.DAYS);
        return !entry.getFileName().endsWith("TAM") //does not take TAM file
                && !entry.getFileName().endsWith("RAM") //does not take RAM file
                && ((dateRechercheeB == null && Math.abs(entryDateDays - TimeUnit.DAYS.toDays(dateRechercheeA.getTime())) <= 1)
                || (dateRechercheeB != null && entryDateDays >= (TimeUnit.DAYS.toDays(dateRechercheeA.getTime()) - 1) && entryDateDays <= (TimeUnit.DAYS.toDays(dateRechercheeA.getTime()) + 1)));
    }
})) {
    Iterator<Path> it = stream.iterator();
    //Iterate good file...

}

The filter is directly made in the accept methods and not after.

JAVA SE 7 - Files - newDirectoryStream()

Upvotes: 3

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