How do I compare data classes in Kotlin?

How do I compare data classes in Kotlin?

In Kotlin, the == operator is the default way to compare two objects. It compares their values by calling equals under the hood. Thus if equals is overridden in your classs, you can compare its instances using == . For reference comparison, you can use the === operator.

How do you get data from kotlin Data class?

Kotlin data class copy() method

  1. data class Product(var item: String, var price: Int)
  2. fun main(agrs: Array) {
  3. val p1 = Product(“laptop”, 25000)
  4. println(“p1 object contain data : $p1”)
  5. val p2 = p1.
  6. println(“p2 copied object contains default data of p1: $p2”)
  7. val p3 = p1.

How do I use Kotlin Data class?

The lesser code, the lesser bugs it can produce and hence Kotlin is preferred over Java by Android Developers….When a class is marked as data class in kotlin, the compiler automatically creates the following:

  1. getters and setters for the constructor parameters.
  2. hashCode()
  3. equals()
  4. toString()
  5. copy()

Can data classes have methods Kotlin?

Data classes have a few limitations when compared to regular classes: They have little utility other than holding data. They can’t be open , abstract , sealed or inner classes. The compiler forbids manually implementing copy() and componentN() methods.

Is Data class immutable Kotlin?

As Kotlin function parameters are immutable, data class members should be also by default, especially if you do lots of functional paradigm.

What is difference between class and data class in Kotlin?

A data class is a class that only contains state and does not perform any operation. The advantage of using data classes instead of regular classes is that Kotlin gives us an immense amount of self-generated code.

What is inner class in Kotlin?

Kotlin Inner class Inner class is a class which is created inside another class with keyword inner. In other words, we can say that a nested class which is marked as “inner” is called inner class. Inner class cannot be declared inside interfaces or non-inner nested classes. class outerClass{ //outer class code.

What is the meaning of in Kotlin?

Kotlin is a static type, object-oriented programing (OOP) language that is interoperable with the Java virtual machine, Java libraries and Android. Kotlin saves time for developers as the less verbose language provides briefer and less redundant code. Kotlin can be compiled into JavaScript or an LLVM encoder.

What does data class mean in Kotlin?

You often create classes whose main purpose is to hold data. In such classes, some standard functionality and utility functions are often mechanically derivable from the data. In Kotlin, these are called data classes and are marked with data : data class User(val name: String, val age: Int) Copied!

How do I make a data class serializable in Kotlin?

Before starting, you’ll need to configure your build script so that you can use Kotlin serialization tools in your project:

  1. Apply the Kotlin serialization Gradle plugin org. jetbrains. kotlin. plugin.
  2. Add the JSON serialization library dependency: org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.1. Groovy. Kotlin.

Are data classes serializable Kotlin?

To use the Kotlin serialization library, we have to integrate both a serialization plugin and a runtime serialization library. The serialization plugin generates the code to parse the JSON without using any reflections. On the other hand, the runtime library uses this code to serialize the data classes.

Is kotlin object serializable?

Kotlin serialization is kotlin-first, compile-time, type-safe, reflection-free and completely multi-platform ready serialization mechanism to convert kotlin objects into data formats like JSON or Protobuf and vice-versa.

How do you use GSON Kotlin?

You can also apply these methods to read and parse JSON file from assets in an Android Application….The steps can be summarized as:

  1. Add Gson library.
  2. Define desired Class or Type (using TypeToken)
  3. Use Gson. fromJson() or Gson. toJson() with Class or Type above.
  4. Use additional package GsonBuilder to get pretty JSON.

How do you make a JSON in Kotlin?

MainActivity. kt

  1. package
  2. import
  3. import android.os.Bundle.
  4. import android.view.View.
  5. import android.widget.ListView.
  6. import android.widget.ProgressBar.
  7. import okhttp3.*
  8. import org.json.JSONArray.

How do I use Kotlin ObjectMapper?

Object Serialization Let’s start with object serialization. In order to serialize and deserialize objects, we’ll need to have an instance of ObjectMapper for Kotlin. Now that we have our mapper, let’s use it to serialize a simple Movie object.

How does kotlin define JSON object?

Writing a JSON Object From Kotlin Object The writeValueAsString() function is our key player here and serializes any object and its fields as a String.

How do I read a JSON file in Kotlin?


  1. put assets folder & JSON file in the right place.
  2. create data class corresponding to JSON content.
  3. use AssetManager to open the File, then get JSON string.
  4. use Gson to parse JSON string to Kotlin object.

What is Jackson’s TypeReference?

Class TypeReference This generic abstract class is used for obtaining full generics type information by sub-classing; it must be converted to ResolvedType implementation (implemented by JavaType from “databind” bundle) to be used.

What is constructCollectionType?

constructCollectionType. public CollectionType constructCollectionType(Class collectionClass, JavaType elementType) Method for constructing a CollectionType . NOTE: type modifiers are NOT called on Collection type itself; but are called for contained types.

What is TypeReference in Java?

TypeReference Class This class represents a generic Java type, retaining information about generics. Code sample. Java. // Construct a TypeReference for a Java generic type. // This pattern should only be used for generic types, for classes use the createInstance factory method.

Does Jackson require serializable?

Unlike Gson, Jackson will require getters for all private fields, otherwise serialization and deserialization won’t work.

Is JSON serializable in Java?

This annotation tells Jackson to use this method to generate the JSON string from the Java object. Typically, if you want to print a serialized object, you override the toString() method. But, by using the@JsonValue annotation, you can define the way in which the Java object is to be serialized.

Does JSON serialize private fields?

All fields, both public and private, are serialized and properties are ignored.

Are private properties serialized?

The advantage of DataContract that you can serialize private fields and your class doesn’t need a default constructor. If you use BinaryFormatter , it will go for your class’ private parts. Mark every class of yours with [Serializable] or you won’t go far…

What is JsonConvert SerializeObject?

SerializeObject(Object, Formatting) Serializes the specified object to a JSON string using formatting. SerializeObject(Object,JsonConverter[]) Serializes the specified object to a JSON string using a collection of JsonConverter.

Can we serialize private variable in C#?

Hence, private variables are not serialized. You cannot serialize private members using XmlSerializer unless your class implements the interface IXmlSerializable.

What is SerializeObject?

serializeObject is a variant of existing $. serialize method which, instead of encoding form elements to string, converts form elements to a valid JSON object which can be used in your JavaScript application.

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