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Java Program to Sort ArrayList of Custom Objects by Property
In this article, we will understand how to sort arrayList of custom objects by property. The ArrayList class extends AbstractList and implements the List interface. ArrayList supports dynamic arrays that can grow as needed.
Array lists are created with an initial size. When this size is exceeded, the collection is automatically enlarged. When objects are removed, the array may be shrunk.
Below is a demonstration of the same −
Suppose our input is −
The list is defined as Java Scala Python Mysql
The desired output would be −
The list after sorting values: Java Mysql Python Scala
Algorithm
Step 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Use the ‘sort’ method to sort the list. Step 5 - Use the ‘compareTo’ method to compare properties of the list. Step 6 - Use the ‘add’ method to add new values to the list. Step 7 - In the main method, create an array list, and invoke the ‘sort’ method. Step 8 - Display the result Step 9 - Stop
Example 1
Here, we bind all the operations together under the ‘main’ function.
import java.util.*;
class CustomObject {
private String custom_property;
public CustomObject(String property){
this.custom_property = property;
}
public String get_custom_property(){
return this.custom_property;
}
}
public class Demo {
public static void print(ArrayList<CustomObject> input_list){
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
}
public static void sort(ArrayList<CustomObject> input_list){
input_list.sort((object_1, object_2)
-> object_1.get_custom_property().compareTo(
object_2.get_custom_property()));
}
public static void add(ArrayList<CustomObject> input_list){
input_list.add(new CustomObject("Java"));
input_list.add(new CustomObject("Scala"));
input_list.add(new CustomObject("Python"));
input_list.add(new CustomObject("Mysql"));
}
public static void main(String[] args){
System.out.println("Required packages have been imported");
ArrayList<CustomObject> input_list = new ArrayList<>();
add(input_list);
System.out.println("The list is defined as ");
print(input_list);
sort(input_list);
System.out.println("\nThe list after sorting values: ");
print(input_list);
}
}Output
Required packages have been imported The list is defined as Java Scala Python Mysql The list after sorting values: Java Mysql Python Scala
Example 2
Here, we encapsulate the operations into functions exhibiting object oriented programming.
import java.util.*;
class CustomObject {
private String custom_property;
public CustomObject(String property){
this.custom_property = property;
}
public String get_custom_property(){
return this.custom_property;
}
}
public class Demo {
public static void main(String[] args){
System.out.println("Required packages have been imported");
ArrayList<CustomObject> input_list = new ArrayList<>();
input_list.add(new CustomObject("Java"));
input_list.add(new CustomObject("Scala"));
input_list.add(new CustomObject("Python"));
input_list.add(new CustomObject("Mysql"));
System.out.println("The number is defined as ");
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
input_list.sort((object_1, object_2)
-> object_1.get_custom_property().compareTo(
object_2.get_custom_property()));
System.out.println("\nThe list after sorting values: ");
for (CustomObject object : input_list) {
System.out.println(object.get_custom_property());
}
}
}Output
Required packages have been imported The number is defined as Java Scala Python Mysql The list after sorting values: Java Mysql Python Scala
Updated on: 30-Mar-2022
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