Generate a mapping of chess code to cartesian coordinates.

ChessCodeToCartesian.java

package app;
import java.util.Map;
import java.util.HashMap;
import java.util.Map.Entry;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;

public class ChessMapping {
    public Map<String, int[]> chessCodeToCartesian;
    public int dim;

    public ChessMapping() {
        chessCodeToCartesian = new HashMap<>();
        dim = 8;
    }

    public void initBoardMapping() {
        String boardCols[] = new String[]{"a", "b", "c", "d", "e", "f", "g", "h"};
        for (int row=0; row < dim; row++) {
            for (int col=0; col < dim; col++) {
                chessCodeToCartesian.put(boardCols[col] + (dim-row), new int[]{row, col});
            }
        }
    }

    public void print() {
        List<String> chessCodes = new ArrayList<>();
        List<Map<String, int[]>> mappings = new ArrayList<>();
        
        for (Entry<String, int[]> entry : chessCodeToCartesian.entrySet()) {
            chessCodes.add(entry.getKey());
        }

        Collections.sort(chessCodes);

        for (String code : chessCodes) {
            Map<String, int[]> m = new HashMap<>();
            int pos[] = chessCodeToCartesian.get(code);
            m.put(code, new int[]{pos[0], pos[1]});
            mappings.add(m);
        }
        
        for (Map<String, int[]> entry : mappings) {
            for (String position : entry.keySet()) {
                System.out.print(position + ": ");
            }
            for (int[] n : entry.values()) {
                System.out.println("[" + n[0] + ", " + n[1] + "]");
            }
        }
    }
}

ChessMapping cm = new ChessMapping();
cm.initBoardMappings();
cm.print();

/*
a1: [7, 0]
a2: [6, 0]
a3: [5, 0]
a4: [4, 0]
a5: [3, 0]
a6: [2, 0]
a7: [1, 0]
a8: [0, 0]
b1: [7, 1]
b2: [6, 1]
b3: [5, 1]
b4: [4, 1]
b5: [3, 1]
b6: [2, 1]
b7: [1, 1]
b8: [0, 1]
c1: [7, 2]
c2: [6, 2]
c3: [5, 2]
c4: [4, 2]
c5: [3, 2]
c6: [2, 2]
c7: [1, 2]
c8: [0, 2]
d1: [7, 3]
d2: [6, 3]
d3: [5, 3]
d4: [4, 3]
d5: [3, 3]
d6: [2, 3]
d7: [1, 3]
d8: [0, 3]
e1: [7, 4]
e2: [6, 4]
e3: [5, 4]
e4: [4, 4]
e5: [3, 4]
e6: [2, 4]
e7: [1, 4]
e8: [0, 4]
f1: [7, 5]
f2: [6, 5]
f3: [5, 5]
f4: [4, 5]
f5: [3, 5]
f6: [2, 5]
f7: [1, 5]
f8: [0, 5]
g1: [7, 6]
g2: [6, 6]
g3: [5, 6]
g4: [4, 6]
g5: [3, 6]
g6: [2, 6]
g7: [1, 6]
g8: [0, 6]
h1: [7, 7]
h2: [6, 7]
h3: [5, 7]
h4: [4, 7]
h5: [3, 7]
h6: [2, 7]
h7: [1, 7]
h8: [0, 7]
*/