Fail on "Use a variable-length argument for the Providers."

Question about the task

Aggregator (part 10)

Java Collections, Level 8, Lesson 15

Resolved

What is wrong with the construct?

public Model(View view, Provider[] providers) throws IllegalArgumentException {
    if (view == null || providers == null || providers.length == 0) {
        throw new IllegalArgumentException();
    } else {
        this.view = view;
        this.providers = providers;
    }
}

View has an update method.
The list of job postings is passed to it to be displayed.
Obviously, only the model will call this method, since only the model gets the data.
It's time to create the model.

1. Create a Model class in the model package.

2. Add two fields: 1) a view, 2) an array of providers.

3. Create a constructor with two parameters: 1) a view, 2) an array of providers.
Throw an IllegalArgumentException if invalid data is passed.

4. Create a public void selectCity(String city) method.

5. Implement the selectCity method:
5.1. get job postings from each provider,
5.2. update the view with the list of job postings from item 5.1.

Requirements:

Create a Model class in the model package.
Add two fields to the Model class: a view and an array of providers.
Create a constructor with two parameters: a view and an array of providers. Throw an IllegalArgumentException if invalid data is passed.
Add a public void selectCity(String city) method to the Model class.
Implement the selectCity method. It must get job postings from each provider and pass them to the view's update method.

package com.codegym.task.task28.task2810; import com.codegym.task.task28.task2810.model.LinkedinStrategy; import com.codegym.task.task28.task2810.model.Provider; public class Aggregator { public static void main(String[] args) { Provider provider = new Provider(new LinkedinStrategy()); Controller controller = new Controller(provider); controller.scan(); } }

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JianQiu Hwang

Level 35 , Washington

17 May 2020, 07:32

solution

After 27 attempts, "Use a variable-length argument for the Providers." means it should be `Provider...` instead of `Provider[]` in the argument.variable-arguments-in-java/

public Model(View view, Provider... providers) throws IllegalArgumentException {
    if (view == null || providers == null || providers.length == 0) {
        throw new IllegalArgumentException();
    } else {
        this.view = view;
        this.providers = providers;
    }
}

yz Backend Developer

17 May 2020, 05:57

first check for null

JianQiu Hwang

Level 35 , Washington

17 May 2020, 07:21

Still failed. Can you show me the code?

public Model(View view, Provider[] providers) throws IllegalArgumentException {
    if (view == null || providers == null) {
        throw new IllegalArgumentException();
    }
    if (providers.length == 0) {
        throw new IllegalArgumentException();
    }
    this.view = view;
    this.providers = providers;
}

yz Backend Developer

18 May 2020, 04:09

whick lvl and task ?

JianQiu Hwang

Level 35 , Washington

18 May 2020, 15:05

Oh, I have solved it by changing `Provider[]` to `Provider...`. Thanks.

yz Backend Developer

18 May 2020, 22:54

nice