Uses of Class
lib.pwss.hash.file_hash_handler.parallel.ParallelFileHashHandler

Demonstration of Parallel and Sequential File Hash Processing

package org.pwss;

import lib.pwss.hash.file_hash_handler.BigFileHashHandler;
import lib.pwss.hash.file_hash_handler.parallel.ParallelFileHashHandler;
import lib.pwss.hash.model.HashForFilesOutput;

import java.io.File;
import java.time.Duration;
import java.time.Instant;

public class Main {
    public static void main(String[] args) {
      
        // Change path name
        File file = new File("C:\\Users\\my_user\\downloads\\folder_with_big_files\\a_big_file.mp4");

        BigFileHashHandler coreHashExtractorInstance = new BigFileHashHandler(-1);

        ParallelFileHashHandler parallelFileHashHandler = new ParallelFileHashHandler(coreHashExtractorInstance);

        Instant startParallel = Instant.now();
        HashForFilesOutput parallelOutput = parallelFileHashHandler.GetAllHashesInParallel(file);
        Instant endParallel = Instant.now();
        Duration parallelExecutingTime = Duration.between(startParallel, endParallel);

        System.out.println(parallelOutput.toString());

        Instant startSequential = Instant.now();
        HashForFilesOutput sequentialOutput = coreHashExtractorInstance.GetAllHashes(file);
        Instant endSequential = Instant.now();
        Duration sequentialExecutionTime = Duration.between(startSequential, endSequential);

        System.out.println(sequentialOutput.toString());

        System.out.printf("Parallel execution time: %d", parallelExecutingTime.toMillis());
        System.out.printf(" Sequential execution time: %d", sequentialExecutionTime.toMillis());

        parallelFileHashHandler.shutdownThreadPool();

    }
}

Asynchronous SHA-3 hashing of a large file

package org.pwss;

import lib.pwss.hash.file_hash_handler.BigFileHashHandler;
import lib.pwss.hash.file_hash_handler.parallel.ParallelFileHashHandler;


import java.io.File;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.stream.IntStream;

public class Main {
    public static void main(String[] args) throws ExecutionException, InterruptedException {

        File file = new File("C:\\Users\\my_user\\downloads\\folder_with_big_files\\a_big_file.mp4");

        BigFileHashHandler coreHashExtractorInstance = new BigFileHashHandler(-1);

        ParallelFileHashHandler parallelFileHashHandler = new ParallelFileHashHandler(coreHashExtractorInstance);

        Future sha3Future = parallelFileHashHandler.calculateSha3HashFuture(file);

        boolean once = false;
        List myIntegerList;

        while (!sha3Future.isDone()) {

            if (!once) {
                System.out.println("Getting SHA3 hash , please wait :) ");
                myIntegerList = IntStream.range(1, 300)
                        .boxed()
                        .toList();

                System.out.printf(
                        "My Integerlist is now of size -> %d and it feels good to do other work while getting this darn future ",
                        myIntegerList.size());
                once = true;

            }

        }

        System.out.println(sha3Future.get());

        parallelFileHashHandler.shutdownThreadPool();

    }
}

lib.pwss.hash.file_hash_handler.parallel.ParallelFileHashHandler