Chess - Composing constraints and solving

/********************************************************
 * Xpress-BCL Java Example Problems
 * ================================
 *
 * file xbchess.java
 * `````````````````
 * Small LP-problem.
 *
 * (c) 2008-2024 Fair Isaac Corporation
 * author: S.Heipcke, Jan. 2000, rev. Mar. 2011
 ********************************************************/

import com.dashoptimization.*;

public class xbchess {
  public static void main(String[] args) {
    try (XPRBprob p = new XPRBprob("Chess"); /* Initialize BCL and create a new problem */
        XPRBexprContext context =
            new XPRBexprContext() /* Release XPRBexpr instances at end of block. */) {
      XPRBvar xs; /* Number of small chess sets to make */
      XPRBvar xl; /* Number of large chess sets to make */

      /****VARIABLES****/
      xs = p.newVar("xs");
      xl = p.newVar("xl");

      /****OBJECTIVE****/
      p.setObj(xs.mul(5).add(xl.mul(20)));
      /* Define & set the obj. function 5*xs + 20*xl */

      /****CONSTRAINTS****/
      /* Define the constraint 3*xs + 2*xl <= 400 */
      p.newCtr("mc_time", xs.mul(3).add(xl.mul(2)).lEql(400));

      /* Define the constraint xs + 3*xl <= 200 */
      p.newCtr("wood", xs.add(xl.mul(3)).lEql(200));

      /****SOLVING****/
      p.setSense(XPRB.MAXIM);
      p.lpOptimize(""); /* Solve the LP-problem */
    }
  }
}