Depth.java

package org.softlang.company.features;

import org.softlang.company.model.*;

import static javaf.syb.Query.*;
import javaf.prelude.*;

/**
 * Compute department nesting depth in a robust manner.
 * The implementation does not make any assumptions other than that there are objects of type Department
 */
public class Depth {

    public static int depth(Company c) {
        return traverse().apply(c);
    }

    public static Function<Object,Integer> traverse() {
        return new Function<Object,Integer>() {
            public Integer apply(Object x) {
                final int result = all(traverse(), max, 0).apply(x);
                return orDefault(
                        new Function<Department,Integer>() {
                            public Integer apply(Department x) {
                                return result+1;
                            }
                        },
                        result).apply(x);
            }
        };
    }

    public static BinaryOperator<Integer> max =
        new BinaryOperator<Integer>() {
            public Integer apply(Integer x1, Integer x2) {
                return Math.max(x1,x2);
            }
        };

}