Strategy Pattern - Comparator

Java

by techbard 2016. 7. 21. 10:27

# Item.java

public class Item {
private String name;
private int value;

public Item(String name, int value) {
this.name = name;
this.value = value;
}

public int getValue() {
return value;
}

public String getName() {
return name;
}
}

# Main.java

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

public class Main {
private static void printItems(List<Item> items) {
for (Item item : items) {
System.out.println(item.getName());
}
}

public static void main(String[] args) {
Item i01 = new Item("alpha", 20);
Item i02 = new Item("beta", 30);
Item i03 = new Item("gamma", 10);

List<Item> items = new ArrayList<>();
items.add(i01);
items.add(i02);
items.add(i03);

System.out.println("Not sorted");
printItems(items);

System.out.println("\n");

Collections.sort(items, new Comparator<Item>() {

@Override
public int compare(Item o1, Item o2) {
if (o1.getValue() > o2.getValue())
return 1;
else if (o1.getValue() < o2.getValue())
return -1;
return 0;
}
});

System.out.println("Sorted by value");
printItems(items);

System.out.println("\n");

Collections.sort(items, new Comparator<Item>() {

@Override
public int compare(Item o1, Item o2) {
return -o1.getName().compareTo(o2.getName());
}
});

System.out.println("Sorted reverse order by name");
printItems(items);
}
}