In the post "Collections algorithm" we have seen about the algorithms reverse,shuffle,swap,fill and replace available in Collections class. Here we will see about the below remaining algorithm available in java.util.Collections.
- rotate - This static method will rotate the specified list forward or backward by a specified distance.To move the list forward provide the distance as positive integer and to move backward provide the distance as negative integer.
- frequency- This static method will return the count of the specified element exist in the specified list.
- min- This static method will return the minimum element of the specified list according to the natural ordering of the element in the list.
- max - This static method will return the maximum element of the specified list according to the natural ordering of the element in the list.
- disjoint - This static method will return true, if the two specified collection has no common elements between them.It will return false, if there is any common element between them.
Below sample program will illustrate how these methods can be used.
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class CollectionsSample {
public static void main(String[] args) {
CollectionsSample collectionsSample= new CollectionsSample();
collectionsSample.rotate();
collectionsSample.frequency();
collectionsSample.min();
collectionsSample.max();
collectionsSample.disjoint();
}
private void rotate() {
List<String> list=initializeList();
System.out.println("Values in the list before rotating:"+list);
Collections.rotate(list,1);
System.out.println("Values in the list after rotating forward by 1 position:"+list+"\n");
list=initializeList();
System.out.println("Values in the list before rotating:"+list);
Collections.rotate(list,-1);
System.out.println("Values in the list after roating backward by 1 position:"+list+"\n");
}
private void frequency() {
List<String> list=initializeList();
System.out.println("Values in the list :"+list);
int count =Collections.frequency(list, "HYUNDAI");
System.out.println("Number of Hyundai element in the list:"+count+"\n");
}
private void min() {
List<String> list=initializeList();
System.out.println("Values in the list:"+list);
String minElement=Collections.min(list);
System.out.println("Minimum element in the list is:"+minElement+"\n");
}
private void max() {
List<String> list=initializeList();
System.out.println("Values in the list:"+list);
String maxElement=Collections.max(list);
System.out.println("Maximum element in the list is:"+maxElement+"\n");
}
private void disjoint() {
List<String> list=initializeList();
List<String> secondList=new ArrayList<String>();
secondList.add("RENUALT");
secondList.add("AUDI");
System.out.println("Values in the first list :"+list);
System.out.println("Values in the second List :"+secondList);
boolean isDisjointList=Collections.disjoint(list, secondList);
if(isDisjointList)
{
System.out.println("Above two list does not have any elements in common");
}
else
{
System.out.println("Above two list have some elements in common");
}
}
private List<String> initializeList()
{
List<String> list= new ArrayList<String>();
list.add("HYUNDAI");
list.add("FORD");
list.add("HYUNDAI");
list.add("ZEN");
list.add("MARUTHI");
return list;
}
}
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OUTPUT:
Values in the list before rotating:[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Values in the list after rotating forward by 1 position:[MARUTHI, HYUNDAI, FORD, HYUNDAI, ZEN]
Values in the list before rotating:[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Values in the list after roating backward by 1 position:[FORD, HYUNDAI, ZEN, MARUTHI, HYUNDAI]
Values in the list :[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Number of Hyundai element in the list:2
Values in the list:[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Minimum element in the list is:FORD
Values in the list:[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Maximum element in the list is:ZEN
Values in the first list :[HYUNDAI, FORD, HYUNDAI, ZEN, MARUTHI]
Values in the second List :[RENUALT, AUDI]
Above two list does not have any elements in common
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