commit files uebung02

uebung02/chess/Piece.java

@@ -0,0 +1,100 @@
+import static java.lang.Integer.signum;
+import static java.lang.Math.abs;
+
+class Piece {
+    Kind kind;
+    Color color;
+    Board board;
+    int row;
+    int col;
+
+    Piece(Kind kind, Color color, Board board, int row, int col) {
+        if (row < 1 || row > 8 || col < 1 || col > 8)
+            throw new IllegalArgumentException("Invalid pos " + row + "/" + col);
+        this.kind = kind;
+        this.color = color;
+        this.board = board;
+        this.row = row;
+        this.col = col;
+        board.add(this);
+    }
+
+    char charRep() {
+        switch (kind) {
+            case QUEEN:
+                return queenCharRep();
+            case KNIGHT:
+                return knightCharRep();
+        }
+        throw new IllegalArgumentException("Unknown piece " + kind);
+    }
+
+    String showPiece() {
+        switch (kind) {
+            case QUEEN:
+                return queenShowPiece();
+            case KNIGHT:
+                return knightShowPiece();
+        }
+        throw new IllegalArgumentException("Unknown piece " + kind);
+    }
+
+    boolean canCapture(Piece other) {
+        switch (kind) {
+            case QUEEN:
+                return queenCanCapture(other);
+            case KNIGHT:
+                return knightCanCapture(other);
+        }
+        throw new IllegalArgumentException("Unknown piece " + kind);
+    }
+
+    char queenCharRep() {
+        if (color == Color.WHITE)
+            return 'q';
+        else
+            return 'Q';
+    }
+
+    char knightCharRep() {
+        if (color == Color.WHITE)
+            return 'n';
+        else
+            return 'N';
+    }
+
+    String queenShowPiece() {
+        return "" + color.toString().toLowerCase() + " queen at (" + row + ", " + col + ")";
+    }
+
+    String knightShowPiece() {
+        return "" + color.toString().toLowerCase() + " knight at (" + row + ", " + col + ")";
+    }
+
+    boolean queenCanCapture(Piece other) {
+        if (board != other.board || color == other.color)
+            return false;
+        if (other.row != row &&
+            other.col != col &&
+            abs(other.row - row) != abs(other.col - col))
+            return false;
+        final int dr = signum(other.row - row);
+        final int dc = signum(other.col - col);
+        int r = row + dr;
+        int c = col + dc;
+        while (r != other.row || c != other.col) {
+            if (board.pieceAt(r, c) != null) return false;
+            r += dr;
+            c += dc;
+        }
+        return true;
+    }
+
+    boolean knightCanCapture(Piece other) {
+        if (board != other.board || color == other.color)
+            return false;
+        final int dr = abs(row - other.row);
+        final int dc = abs(col - other.col);
+        return dr == 2 && dc == 1 || dr == 1 && dc == 2;
+    }
+}