Java List Sort sort(List> listOfClassDataList)

Description

Sort outer list by using first element of inner list

License

Apache License

Declaration

public static <T extends Comparable<? super T>> void sort(List<List<T>> listOfClassDataList) 

Method Source Code

//package com.java2s;
/*//  w w  w  .  j a  v a2 s.c om
 * #%L
 * Java Static Code Analysis
 * %%
 * Copyright (C) 2013 Andreas Behnke
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class Main {
    public static <T extends Comparable<? super T>> List<T> sort(Collection<T> set) {
        List<T> sorted = new ArrayList<T>();
        sorted.addAll(set);
        Collections.sort(sorted);
        return sorted;
    }

    /**
     * Sort outer list by using first element of inner list
     */
    public static <T extends Comparable<? super T>> void sort(List<List<T>> listOfClassDataList) {

        Collections.sort(listOfClassDataList, new Comparator<List<T>>() {
            @Override
            public int compare(List<T> o1, List<T> o2) {
                // null check
                if (o1 == null && o2 == null) {
                    return 0;
                }
                if (o1 == null && o2 != null) {
                    return -1;
                }
                if (o1 != null && o2 == null) {
                    return 1;
                }

                // empty check
                int size1 = o1.size();
                int size2 = o2.size();
                if (size1 == 0 || size2 == 0) {
                    if (size1 == size2) {
                        return 0;
                    }
                    return (size1 > size2) ? 1 : -1;
                }

                // first element check
                return o1.get(1).compareTo(o2.get(1));
            }
        });

    }
}

Related

1. sort(List list)
2. sort(List list, Comparator comparator)
3. sort(List list1, List list2)
4. sort(List list)
5. sort(List source)
6. sort(List> lists)
7. sort(List lists)
8. sort(List list)
9. sort(List list)