Sort an ArrayList with another using Java

Sort an ArrayList with another ArrayList

This java sample helps you to understand how you can sort an ArrayList with another ArrayList.

Step 1: 

Create class SampleSort. Follow below program.

package com.sample;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 *
 * @author Vimal Sanker
 *
 */
public class SampleSort {

public static void main(String[] args) {
                List<String> listA = java.util.Arrays.asList("Monday","Thursday","Sunday","Tuesday","Saturday","Wednesday","Friday");
                List<String> listB = java.util.Arrays.asList("Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday");
                Map<String, Integer> day = new HashMap<String, Integer>();
                for(int i=0;i<listB.size();i++) {
                        String day2 = listB.get(i);
                        day.put(day2, i);
                }
                Collections.sort(listA, new CustomFieldComparator(day));
                for(String s : listA) {
                        System.out.println(s);
                }
        }
}

Above program have two ArrayList, listA and listB. Here we are trying to sort listA with listB.

Step 2:

Create class CustomFieldComparator. Follow below program.

package com.Sample;

import java.util.Comparator;

import java.util.Map;

/**

 * 

 * @author Vimal Sanker

 *

 */

public class CustomFieldComparator implements Comparator<String> {

        private Map<String, Integer> sortOrder;

        public CustomFieldComparator(Map<String, Integer> sortOrder) {

                this.sortOrder = sortOrder;

        }

        public int compare(String il, String i2) {

                Integer weekdayPos1 = sortOrder.get(il.trim());

                if (weekdayPos1 == null) {

                        throw new IllegalArgumentException("Bad name encountered: "+ il);

                }

                Integer weekdayPos2 = sortOrder.get(i2);

                if (weekdayPos2 == null) {

                        throw new IllegalArgumentException("Bad name encountered: "+ i2);

                }

                return weekdayPos1.compareTo(weekdayPos2);

         }

}

This is Comparator class which will help us to do the sorting. This is a custom class created as per the requirement.

Step 3:

Execute class SampleSort.

Output:

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

............................................................................................................................................

Enjoy.....