Sudoku使用lambda和Java中的Callable进行多线程处理(Sudoku Multithreading with lambda and Callable in Java)

 我做了一个程序，检查完成的9x9数独矩阵是否正确。 我想创建线程来同时检查行，列和区域，看看数字1-9是否出现在它们中。 我是使用Callable和lambda的新手。 这是我到目前为止的代码： 
 
public class Sudoku {

    public boolean testBoard(int[][] board) throws InterruptedException, ExecutionException {
        List<Callable<Boolean>> tests = new ArrayList<>();
        tests.add(() -> testCols(board));
        tests.add(() -> testRegions(board));
        tests.add(() -> testRows(board));
        tests.add(() -> testSize(board));

        /*Maybe store this threadPool in a field so you dont create it everytime*/
        ExecutorService threadPool = Executors.newCachedThreadPool();
        List<Future<Boolean>> results = threadPool.invokeAll(tests);

        for (Future<Boolean> future : results) {
            if (!Boolean.TRUE.equals(future.get())) {
                return false;
            }
        }
        return true;
    }

    // check that the board is 9 x 9
    boolean testSize(int[][] board) {
        if (board.length != 9) {
            return false;
        }
        for (int i = 0; i < board.length; i++) {
            if (board[i].length != 9) {
                return false;
            } else;
        }
        return true;
    }

    // check that the digits 1-9 each appear exactly once in the given array
    boolean checkDigits(int[] array) {
        if (array.length != 9) {
            return false;
        }
        int[] counts = new int[10];
        for (int i = 0; i
                < array.length; i++) {
    // invalid number
            if (array[i] < 1 || array[i] > 9) {
                return false;
            }
    // we have already seen this number
            if (counts[array[i]] > 0) {
                return false;
            }
            counts[array[i]]++;
        }
        return true;
    }
    // return true if all rows are correct

    boolean testRows(int[][] board) {
        for (int i = 0; i < board.length; i++) {
            if (!checkDigits(board[i])) {
                return false;
            }
        }
        return true;
    }
    // return true if all columns are correct

    boolean testCols(int[][] board) {
        int[] tmp = new int[board.length];
        for (int col = 0; col < board.length; col++) {
    // fill a temp array with every element of the column
            for (int row = 0; row < board.length; row++) {
                tmp[row]
                        = board[row][col];
            }
    // check to make sure it has all the right digits
            if (!checkDigits(tmp)) {
                return false;
            }
        }
        return true;
    }
    // return true if every region is correct

    boolean testRegions(int[][] board) {
    //loop through each region, passing the indices of the upper-left corner to the next method
    //note that we increment row and column counters by 3 here
        for (int row = 0; row < board.length; row += 3) {
            for (int col = 0; col
                    < board.length; col += 3) {
                if (!testRegion(board, row, col)) {
                    return false;
                }
            }
        }
        return true;
    }
    // test a specific region, given the upper left corner

    boolean testRegion(int[][] board, int startRow, int startCol) {
        int[] tmp = new int[board.length];
    // fill a temporary array with every element of the region
        int index = 0;
        for (int row = startRow; row < startRow + 3; row++) {
            for (int col = startCol; col < startCol + 3; col++) {
                tmp[index]
                        = board[row][col];
                index++;
            }
        }
    // check if we have all of the right digits in the region
        return checkDigits(tmp);
    }
}
 
 
public class TestPuzzle {

    public static void testpuzzle() throws FileNotFoundException, InterruptedException, ExecutionException{
        Sudoku sudoku = new Sudoku();
        String fileName = "SudokuRight.txt";//This is for the print statment
        Scanner inputStream = null;
        String[] line;
        System.out.println("The file " + fileName + " contains the following sudoku puzzle:\n");
        inputStream = new Scanner(new File("C:\\Users\\username\\Documents\\NetBeansProjects\\Sudoku\\SudokuRight.txt"));
        int[][] puzzle = new int[9][9];
        int row = 0;
        while (inputStream.hasNextLine()) {
            line = inputStream.nextLine().split(",");
            for (int i = 0; i < 9; i++) {
                puzzle[row][i] = Integer.parseInt(line[i]);
            }
            row++;
        }
        for (int i = 0; i < 9; i++) {
            System.out.println(Arrays.toString(puzzle[i]));
        }

        boolean result = sudoku.testBoard(puzzle);
        System.out.println("Result: " + result);
        if (result == true) {
            System.out.println("This sudoku solution IS valid!");
        } else if (result == false) {
            System.out.println("This sudoku solution IS NOT valid!");
        }
    }
}
 
 
public class Main {

    //This is the main method to check the validity of sudoku puzzles
    public static void main(String[] args) throws FileNotFoundException, InterruptedException, ExecutionException {
        TestPuzzle.testpuzzle();
    }
}
 
 有人试图教我使用callable和lambda，但我仍然有些困惑。 我的代码现在正确运行，但是，在NetBeans打印出结果后，它会继续运行，直到我手动终止它为止。 我不知道为什么？ 我以为我必须在我的代码中有一个语句块，如下所示： 
 
Callable<Boolean> callable = () -> Boolean.valueOf(testCols(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testRows(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testRegions(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testSize(board));
 
 但是我不确定把这些行放在哪里？ 我不能把它们放在构造函数中，因为“board”还没有被初始化。 我确信这是一个简单的解决方法，因为我刚刚接触这个，所以我只是被卡住了。 请帮忙吗？ 

I made a program that checks to see if a finished 9x9 Sudoku matrix is correct or not. I wanted to create threads that checked the rows, columns, and regions at the same time to see if the numbers 1-9 appeared in them. I am new to using Callable and lambda. Here is my code so far:
 
public class Sudoku {

    public boolean testBoard(int[][] board) throws InterruptedException, ExecutionException {
        List<Callable<Boolean>> tests = new ArrayList<>();
        tests.add(() -> testCols(board));
        tests.add(() -> testRegions(board));
        tests.add(() -> testRows(board));
        tests.add(() -> testSize(board));

        /*Maybe store this threadPool in a field so you dont create it everytime*/
        ExecutorService threadPool = Executors.newCachedThreadPool();
        List<Future<Boolean>> results = threadPool.invokeAll(tests);

        for (Future<Boolean> future : results) {
            if (!Boolean.TRUE.equals(future.get())) {
                return false;
            }
        }
        return true;
    }

    // check that the board is 9 x 9
    boolean testSize(int[][] board) {
        if (board.length != 9) {
            return false;
        }
        for (int i = 0; i < board.length; i++) {
            if (board[i].length != 9) {
                return false;
            } else;
        }
        return true;
    }

    // check that the digits 1-9 each appear exactly once in the given array
    boolean checkDigits(int[] array) {
        if (array.length != 9) {
            return false;
        }
        int[] counts = new int[10];
        for (int i = 0; i
                < array.length; i++) {
    // invalid number
            if (array[i] < 1 || array[i] > 9) {
                return false;
            }
    // we have already seen this number
            if (counts[array[i]] > 0) {
                return false;
            }
            counts[array[i]]++;
        }
        return true;
    }
    // return true if all rows are correct

    boolean testRows(int[][] board) {
        for (int i = 0; i < board.length; i++) {
            if (!checkDigits(board[i])) {
                return false;
            }
        }
        return true;
    }
    // return true if all columns are correct

    boolean testCols(int[][] board) {
        int[] tmp = new int[board.length];
        for (int col = 0; col < board.length; col++) {
    // fill a temp array with every element of the column
            for (int row = 0; row < board.length; row++) {
                tmp[row]
                        = board[row][col];
            }
    // check to make sure it has all the right digits
            if (!checkDigits(tmp)) {
                return false;
            }
        }
        return true;
    }
    // return true if every region is correct

    boolean testRegions(int[][] board) {
    //loop through each region, passing the indices of the upper-left corner to the next method
    //note that we increment row and column counters by 3 here
        for (int row = 0; row < board.length; row += 3) {
            for (int col = 0; col
                    < board.length; col += 3) {
                if (!testRegion(board, row, col)) {
                    return false;
                }
            }
        }
        return true;
    }
    // test a specific region, given the upper left corner

    boolean testRegion(int[][] board, int startRow, int startCol) {
        int[] tmp = new int[board.length];
    // fill a temporary array with every element of the region
        int index = 0;
        for (int row = startRow; row < startRow + 3; row++) {
            for (int col = startCol; col < startCol + 3; col++) {
                tmp[index]
                        = board[row][col];
                index++;
            }
        }
    // check if we have all of the right digits in the region
        return checkDigits(tmp);
    }
}
 
 
public class TestPuzzle {

    public static void testpuzzle() throws FileNotFoundException, InterruptedException, ExecutionException{
        Sudoku sudoku = new Sudoku();
        String fileName = "SudokuRight.txt";//This is for the print statment
        Scanner inputStream = null;
        String[] line;
        System.out.println("The file " + fileName + " contains the following sudoku puzzle:\n");
        inputStream = new Scanner(new File("C:\\Users\\username\\Documents\\NetBeansProjects\\Sudoku\\SudokuRight.txt"));
        int[][] puzzle = new int[9][9];
        int row = 0;
        while (inputStream.hasNextLine()) {
            line = inputStream.nextLine().split(",");
            for (int i = 0; i < 9; i++) {
                puzzle[row][i] = Integer.parseInt(line[i]);
            }
            row++;
        }
        for (int i = 0; i < 9; i++) {
            System.out.println(Arrays.toString(puzzle[i]));
        }

        boolean result = sudoku.testBoard(puzzle);
        System.out.println("Result: " + result);
        if (result == true) {
            System.out.println("This sudoku solution IS valid!");
        } else if (result == false) {
            System.out.println("This sudoku solution IS NOT valid!");
        }
    }
}
 
 
public class Main {

    //This is the main method to check the validity of sudoku puzzles
    public static void main(String[] args) throws FileNotFoundException, InterruptedException, ExecutionException {
        TestPuzzle.testpuzzle();
    }
}
 
Someone was trying to teach me about using callable and lambda, but I'm still slightly confused. My code does run correctly right now, however, in NetBeans after it prints out the results it continues to run until I manually terminate it. I'm not sure why? I thought I had to have a block of statements in my code like this:
 
Callable<Boolean> callable = () -> Boolean.valueOf(testCols(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testRows(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testRegions(board));
Callable<Boolean> callable = () -> Boolean.valueOf(testSize(board));
 
However I'm not sure where to put these lines? I can't put them in the constructor because "board" hasn't been initialized yet. I'm sure this is an easy fix, I'm just stuck since I'm new to this. Any help please?

原文：https://stackoverflow.com/questions/33468863