Example of Collections.binarySearch(), in List of Date

Collections.binarySearch() searches the specified list for the specified object using the binary search algorithm. Details refer to the Java doc.

Example:

package javaapplication1;

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

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JavaApplication1 {

    public static void main(String[] args) {
        
        Comparator<Date> comparator = new Comparator<Date>() {

            @Override
            public int compare(Date o1, Date o2) {
                return o1.compareTo(o2);
            }
        };
        
        List<Date> myList = new ArrayList<>();
        myList.add(new Date(2015-1900, 01, 01));
        myList.add(new Date(2013-1900, 01, 01));
        myList.add(new Date(2013-1900, 01, 02));
        myList.add(new Date(2012-1900, 10, 01));
        myList.add(new Date(2012-1900, 11, 01));
        myList.add(new Date(2015-1900, 01, 10));
        
        Collections.sort(myList, comparator);
        
        //Print all the elements in the List
        for(int i = 0; i < myList.size(); i++){
            System.out.println(myList.get(i).toString());
        }
        
        //find the closest element from the List
        Date target = new Date(2013-1900, 01, 02);
        int index = Collections.binarySearch(
                myList, 
                target, 
                comparator);
        System.out.println("closest to " + target.toString() + " : " + index);
        
        target = new Date(2013-1900, 01, 03);
        index = Collections.binarySearch(
                myList, 
                target, 
                comparator);
        System.out.println("closest to " + target.toString() + " : " + index);
        
        target = new Date(2012-1900, 10, 02);
        index = Collections.binarySearch(
                myList, 
                target, 
                comparator);
        System.out.println("closest to " + target.toString() + " : " + index);
    }

}

Example of Collections.binarySearch()