类型块问题的未定义方法

Question

我一直在做一个用Java编写国际象棋的项目。我有一个名为Piece的抽象类，它有一个抽象方法和两个普通方法。每个棋子我都有一个类，它们都扩展了棋子。

有一个类也代表棋盘，叫做Board。在这个类中，我有一个方法来检查给定位置的棋子是否属于另一个玩家。在这个方法中，我调用了一个来自Piece类的方法，该方法获取名为getColor（）的颜色。当我在一个棋子上调用这个方法时，它说“方法getColor（）对于类型Piece是未定义的”，即使它是在Piece类中创建的方法。我真的不知道该怎么解决这个问题。

下面是Piece类代码：

abstract class Piece {
    private Color color;

    /**
     * @param color the color of the piece.
     */
    public Piece(Color color) {
        this.color = color;
    }

    /**
     * This method gives a list of all legal moves a piece at a given position in a
     * given board can do.
     * 
     * @param position the position of the piece in the board.
     * @param board    the board in which the piece is in.
     * @return a list of all legal moves.
     */
    abstract List<Position> getPossibleMoves(Position position, Board board);


    /**
     * @return the color of the piece.
     */
    public Color getColor() {
        return color;
    }

下面是板课程代码：

public class Board {
    private Square[][] square;

    /**
     * Initialises an 8 by 8 squares 2d table.
     */
    public Board() {
        this.square = new Square[8][8];
        for (int row = 0; row < square.length; row++) {
            for (int column = 0; column < square.length; column++) {
                square[row][column] = new Square<>(null);
            }
        }
    } 

     /**
     * This method sets the given piece in the given position in the board.
     * Throw an exception if the position is not in the board.
     * 
     * @param piece    The piece to be set.
     * @param position The position to set the piece in.
     */
    public <Piece> void setPiece(Piece piece, Position position) {
        if (piece instanceof Piece) {
            if (contains(position)) {
                square[position.getRow()][position.getColumn()].setPiece(piece);
            } else {
                throw new IllegalArgumentException("The given position isn't part of the board :" + position);
            }
        }
    }

    /**
     * This method returns the piece that is in the given position in the board.
     * Throws an exception if the position is not in the board.
     * 
     * @param pos The position of the piece in the board.
     * @return the piece.
     */
    public <Piece> Piece getPiece(Position pos) {
        Piece piece;
        if (contains(pos)) {
            piece = (Piece) square[pos.getRow()][pos.getColumn()].getPiece();
        } else {
            throw new IllegalArgumentException("The given position isn't part of the board :" + pos);
        }
        return piece;
    }
     /**
     * This method determines whether or not the piece at the given position has the
     * same or the opposite color as the given color.
     * throws an exception if position is not in the board.
     * 
     * @param pos the position of the piece to be checked.
     * @param col the color to check if the piece is in the opposite color or not.
     * @return true if the piece is in the opposite color, false otherwise.
     */
    public <Piece> boolean containsOppositeColor(Position pos, Color col) {
        boolean containsOpposite = false;
        if (contains(pos)) {
            if (!isFree(pos)) {
                Piece piece = getPiece(pos);
                containsOpposite = (col.opposite() == piece.getColor());
            }
        } else {
            throw new IllegalArgumentException("The given position isn't part of the board :" + pos);
        }
        return containsOpposite;
    }

问题出在这样一行：containsPosite=（col.containst（）==piece）。getColor（））




Answer 1

问题是您定义了一个泛型类型

比如说

public <Piece> Piece getPiece(Position pos)

应该是

public Piece getPiece(Position pos)

其他方法也是如此：

public <Piece> void setPiece(Piece piece, Position position)

应该是

public void setPiece(Piece piece, Position position)

和

public <Piece> boolean containsOppositeColor(Position pos, Color col)

应该是

public boolean containsOppositeColor(Position pos, Color col)