flutter_entity

Description:

flutter entity

Abouts #
Entity: #


The Entity class represents an object or data structure that encapsulates information
and behavior related to a specific entity in a domain. It typically contains properties and
methods to manage the state and behavior of the entity.


Entities are commonly used to model real-world objects or concepts within an application,
such as users, products, orders, etc. They provide a structured way to organize and manipulate
data, enabling operations like creation, retrieval, update, and deletion (CRUD) within the
application.


Response: #


The Response class represents a response or result from an operation performed within
an application. It encapsulates information about the outcome of the operation, including any data
produced, status indicators, error messages, and other relevant metadata.


Responses are used to communicate the outcome of operations, such as API requests,
database queries, or internal function calls, within an application. They provide a standardized
way to convey success, failure, or other states, allowing the application to handle and respond to
different scenarios appropriately. Responses often include data payloads to convey results or
errors back to the caller.


Usage #
First, let's define a simple user entity: #
import 'entity.dart';

class User extends Entity<EntityKey> {
String? name;
int? age;

User({
String? id,
int? timeMills,
this.name,
this.age,
}) : super(id: id, timeMills: timeMills);

@override
String toString() {
return 'User{id: $id, name: $name, age: $age, timeMills: $timeMills}';
}
}
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Now, let's define a method to create a user entity and return a response: #
import 'response.dart';

Response<User> createUser(String name, int age) {
final response = Response<User>();
try {
// Simulate creating a user entity with an auto-generated ID and timestamp
User user = User(name: name, age: age);

// Simulate a successful response with the created user entity
return response.withData(user, message: 'User created successfully');
} catch (e) {
// If an error occurs during user creation, return an error response
return response.withException('Failed to create user');
}
}
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Next, let's define a method to retrieve a user entity by ID and return a response: #
Response<User> getUser(String userId) {
final response = Response<User>();
try {
// Simulate fetching user data from a database or external API
User user = User(id: userId, name: 'John Doe', age: 30);

// Simulate a successful response with the fetched user entity
return response.withData(user, message: 'User fetched successfully');
} catch (e) {
// If an error occurs during user retrieval, return an error response
return response.withException('Failed to fetch user');
}
}
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Finally, let's create a main function to test our methods: #
void main() {
// Creating a new user
Response<User> createUserResponse = createUser('Alice', 25);
print(createUserResponse.message); // User created successfully
print(createUserResponse.data); // User{id: 1634743202815, name: Alice, age: 25}

// Fetching an existing user
String userId = createUserResponse.data?.id ?? '';
Response<User> getUserResponse = getUser(userId);
print(getUserResponse.message); // User fetched successfully
print(getUserResponse.data); // User{id: 1634743202815, name: John Doe, age: 30}
}
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