ObjectHelper Tutorial

This tutorial provides an overview of the ObjectHelper class, which is part of the lightweight-component/aj-util library. The ObjectHelper class provides utility methods for working with Java objects.

Introduction

The ObjectHelper class contains static methods for object cloning and map creation utilities.

Main Features

• Deep cloning of Serializable objects
• Convenient map creation methods
• Optimized map initialization
• Empty map constant

Constants

1. EMPTY_PARAMS_MAP - Immutable empty map

Methods

1. Cloning

1. clone(T obj) - Deep clone a Serializable object

2. Map Creation

1. mapOf(K k1, V v1) - Create map with single entry
2. mapOf(K k1, V v1, K k2, V v2) - Create map with two entries
3. mapOf(K k1, V v1, K k2, V v2, K k3, V v3) - Create map with three entries
4. mapOf(int expectedSize) - Create optimized HashMap with expected size

Usage Examples

Object Cloning

MyClass original = new MyClass();
MyClass cloned = ObjectHelper.clone(original);

Map Creation

Map<String, Integer> map1 = ObjectHelper.mapOf("a", 1);
Map<String, Integer> map2 = ObjectHelper.mapOf("a", 1, "b", 2);
Map<String, Integer> map3 = ObjectHelper.mapOf("a", 1, "b", 2, "c", 3);

// Optimized map
Map<String, Integer> map = ObjectHelper.mapOf(100); // Pre-sized for ~100 entries

Empty Map

Map<String, Object> empty = ObjectHelper.EMPTY_PARAMS_MAP;

Implementation Notes

• clone() uses Java serialization for deep cloning
• mapOf() methods provide convenient map initialization
• mapOf(int) optimizes HashMap creation by calculating ideal initial capacity

Conclusion

The ObjectHelper class provides useful utilities for object cloning and map creation, simplifying common object-related operations in Java applications.