IO. Practice Task 2

1. Json Output Stream

Your task is to create implementation IJsonOutputStream interface that should be named as JsonOutputStream and should also be a Filtering stream - so you need to extend FilterOutputStream also.

The only method that should be implemented is writeJson that consumes object of type JsonType and performs write operation.

To show usage of your stream you need to implement all reasonable JSON related data types:

• Json String
• Json Number
• Json Array
• Json Object
• Json Boolean

All this types should implement JsonType interface.

Json String

This data type should be an immutable data type that is actually just wrapper above regular java String.

Strings in JSON format are just quoted sequence of characters:

"I need to use Quotes(\")"

Json Number

This data type should be an immutable data type that is actually just wrapper above regular java Number.

Numbers in JSON format are represented by their values.

Json Array

This data type should be an immutable data type that is actually just wrapper above java Collection of other JsonType objects.

Arrays in JSON format are represented as in example below:

[1,2,"3",4,{"property":"value"},[1,2]] 

So, you see, that there are no restrictions for data types that are actually in the array.

Json Object

This data type should be an immutable data type that is actually just wrapper above java Map of String keys and JsonType values.

Objects in JSON format have following representation:

{
    "string": "value",
    "list": [1, 2, 3, "String"],
    "anotherEmptyObject": {},
    "anotherObject": {
    	"key": "value"
    },
    "boolean": true,
    "null": null,
    "integer": 1,
    "double": 2.2
}

Json Boolean

This data type should be an immutable data type that is actually just wrapper above regular java Boolean.

Boolean should be represented as true or false

Demo

You should create Demo class and show usage of your implementation.

In your demo you need to create complex JsonObject and save it to the file called demo.json.

You should also demonstrate usage of your stream with System.out stream.

jUnit test

You should create jUnit tests for all your JSON types and JsonOutputStream.