Java List Permutate permutations(Map> parameterValues)

Description

permutations

License

Apache License

Declaration

public static <T> List<Map<String, T>> permutations(Map<String, List<T>> parameterValues) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.util.*;

public class Main {
    public static <T> List<Map<String, T>> permutations(Map<String, List<T>> parameterValues) {
        List<Map<String, T>> list = new ArrayList<Map<String, T>>();
        if (parameterValues == null || parameterValues.size() == 0) {
            return list;
        }/*from w ww . ja  v a 2  s.  co  m*/

        permute(new HashMap<String, T>(), new ArrayList<String>(parameterValues.keySet()), parameterValues, list);

        return list;

    }

    private static <T> void permute(Map<String, T> basePermutation, List<String> remainingKeys,
            Map<String, List<T>> parameterValues, List<Map<String, T>> returnList) {

        String thisKey = remainingKeys.get(0);
        remainingKeys = remainingKeys.subList(1, remainingKeys.size());
        for (T value : parameterValues.get(thisKey)) {
            Map<String, T> permutation = new HashMap<String, T>(basePermutation);

            permutation.put(thisKey, value);

            if (remainingKeys.size() == 0) {
                returnList.add(permutation);
            } else {
                permute(permutation, remainingKeys, parameterValues, returnList);
            }
        }
    }
}

Related

1. permutate(List src)
2. permutation(List list1, List list2, String token)
3. permutation(String prefix, String s, List list)
4. permutations(List list)
5. permutations(List listings)
6. permute(List s1, List s2)
7. permute(List arr)
8. permute(List list1)
9. permute(List list, int index, List> result)