[Core Java] Serialization & Deserialization


Objects can be flattened and inflated. Objects have state and behavior. Behaviour lies in the class but state lives in each individual object. So what happens when its time to save the state of an object? If you are writing a game, you would need a Save & Restore Game feature. Luckily there is a feature built in java which is to simply freeze-dry/ flatten / persist / dehydrate the object itself to save the state and reconstitute / inflate / restore / rehydrate to get it back. 

You have lots of options for how to save the state of your Java Program, and what you will choose will probably depend on how you plan to use the saved state. Here are the options we will be looking at in this chapter.
 
If your data will be used by only the Java program that generated it: 
Use serialization
Write a file that holds flattened (serialized) objects. Then have your program read the serialized objects from the file and inflate them back into living, breathing, heap-inhabiting objects. 

If your data will be used by other programs:
Write a plain text file
Write a file, with delimiters that other programs can parse. For example, a tab-delimited file that a spreadsheet or database application can use. 

Saving State
1. Option One:
Write the three serialized character objects to a file
Create a file and write three serialized character objects. The file won’t make sense if you try to read it as text.

2. Option Two:
Write a plain text file
Create a file and write three lines of text, one per character, separating the pieces of state with commas:

50, Elf, bow, sword, dust 
200, Troll, bare hands, big ax 
120, Magician, spells, invisibility 

Write a serialized object to a File
Following are the steps to create a seriliazed object:


1. Make a FileOutputStream
FileOutputStream fileStream = new FileOutputStream(“MyGame.ser”);

2. Make an ObjectOutputStream
ObjectOutputStream os = new ObjectOutputStream(fileStream);

3. Write the object
os.writeObject(characterOne); 
os.writeObject(characterTwo); 
os.writeObject(characterThree);

4. Close the ObjectOutputStream
os.close(); 



Deserialization
Following picture explains how deserialization works:




Comments

Post a Comment

Popular posts from this blog

[SVN] Simple way to do code review

Image
Simple way to do code review Table of Contents A code review (also known as code inspection or walkthrough ) is often considered to be a complex, time consuming and highly regulated process. In reality it’s just another form of communication between team members and a great way to ensure code quality and stay up to date with changes. In this guide we will show a simple and effortless way to do it on a daily basis. Use version control We hope you are already doing this! Version control systems make any work inside your team much easier, and this includes code reviews. Check out our guide “Introduction to version control” if you are still managing code the old-fashion way, or are interested in learning some best practices. Stay up to date Email and RSS are common ways to be notified about new things and code changes are not exceptions. Depending on the project scope and team size you can choose between checking every commit or just doing review o
Read more

How to Choose a Technology Stack for Web Application Development

Image
What’s the most important thing to consider when you’re developing a top-notch web application? No doubt it’s the technology stack your app will be based upon.  The choice of a relevant tech stack is particularly challenging for small businesses and startups, since they usually have limited budgets and, thus, need a technology stack that provides the most bang for the buck to get their projects off the ground. The right tech stack is, to a great extent, the key to your project’s success, while the wrong choice of web development technologies may be a reason for failure. We’ve decided to give you a helping hand and reveal the criteria for choosing the most appropriate tech stack for your web application. WHAT IS A TECHNOLOGY STACK FOR WEB DEVELOPMENT Before moving on to the criteria for choosing a modern web technology stack, you should clearly understand what comprises the process of web development. Without going too deep into details, there are two sides to web de
Read more

Setting ESLint on a React Typescript project

Image
  Introduction After struggling a lot trying to install and understand ESLint on my React Typescript project, I decided to create a definitive guide to setting ESLint to a React Typescript project. The main goal of this tutorial is to set up step-by-step and explain every line added or executed, instead of just giving you a bunch of files with a lot of configurations and expecting that you will be able to understand what and how things are happening. So, let’s start! Prerequisites Note: You need Node version >= 10 installed. So, if you don’t have it, please go to the NodeJS website, and download and install it on your local machine. ( https://nodejs.org/en/ ) Step 1: Create a React Project with Typescript The following command will create a project inside a folder  my-app . On the terminal, run: npx create-react-app my-app --template typescript Step 2: Removing the pre-set ESLint configuration from React project React comes with an eslint configuration pre-setted. Let’s remove this
Read more