Question

I would like to know if it is possible to apply a function to all files in a directory using Java?

More specifically, I am looking to read in all images in a folder, convert them to binary (two colours/black and white), and then save the binary image as a new image in another directory (probably directory\binary, for example).

Something like this:

for(all images in folder)
    read in image
    make(binaryImg)
    saveNewImage
endFor

I have 300 images so was hoping that there is a way to do this?

Many thanks.

Answer 1

You can do it this way:

File dir = new File("/dir/");
for(File f : dir.listFiles())
  processImage(f);

Of course, since you have many files, you can create a Runnable for every file and pass them to an ExecutorService to process in multiple threads:

public static void main(String... args){

    ExecutorService pool = Executors.newFixedThreadPool(4); //nbr of active threads

    File dir = new File("/dir/");
    for(File f : dir.listFiles())
    pool.submit(new Runnable() {
         public void run(){
             processImage(f);
        }
    } 
}