Couple of questions in regards to this task

Question about the task

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1) Can someone please refer me to another article or maybe tutorial as I am very confused about the usage of the keyword 'this'. I do understand that we use it in the constructor of the class Today but why do we have to use it in the return value of the getWeatherType() 2) How are they related to each other? We're invoking the getWeatherType in the class Today which returns the value why do we use this.type 3) Why do we need String in the WeatherType interface as they are CONSTANTS? or also in the interface Weather why the word String and not final for instance? 4) Why are the interfaces in separate files? They are not classes? I hope someone can explain these to me. Thanks in advance

1. Make the Today class implement the Weather interface.
2. Think about the relationship between the parameter type and the getWeatherType() method.
3. The Weather and WeatherType interfaces are already implemented in separate files.

Requirements:

The Today class must implement the Weather interface.
The Weather interface's getWeatherType method must be implemented in the Today class.
The getWeatherType method must return a String.
The getWeatherType method must return the value of the variable type.

package com.codegym.task.task13.task1317; /* Nice weather */ public class Solution { public static void main(String[] args) { System.out.println(new Today(WeatherType.CLOUDY)); System.out.println(new Today(WeatherType.FOGGY)); System.out.println(new Today(WeatherType.FREEZING)); } static class Today implements Weather { private String type; Today(String type) {//constructor with parameter String type) this.type = type; } public String getWeatherType(){ return this.type; } @Override public String toString() { return String.format("Today it will be %s", this.getWeatherType()); } } }

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Anthony Chalk

Level 30 , London, United Kingdom

14 March 2020, 15:38

useful

1) when we say "this" we're referring to the class in which it is written. You don't need to use it in the getWeatherType() method; remove it and see what happens. In the constructor we use it because the type field (line 16) and the type passed argument (line 18) have the same name - so we want to make clear that we're assigning the value on line 18 to line 16. 2) Not to sure what the question is 3) Any variable can be a constant, you still need to declare the variable type. And obviously, whichever type you declare will effect what you can then do with it. Final isn't a variable type, it's a modifier 4) They can still be in separate files. Imagine you have an interface that you want multiple classes to implement, it would make sense for it to be in a separate file. It may not be necessary for this particular task, but it's useful to know the different ways you can do things and what the advantages/disadvantages are for each way

Liliane Top

Level 17 , Amsterdam, Netherlands

14 March 2020, 16:25

Hi Anthony, thanks for taking the time to explain. It certainly is very helpful. 1) it's now clear to what the keyword 'this' refers to in this context. I tried to remove this from the return value but I am not allowed to change an already verified solution. But I'll try to do this in intellij. 2) is already answered by answer 1 3) wauh I just never realised this fact. Now I will not make that mistake again. Final is a modifier!! I thought it to be a type as in a CONSTANT 4) good to know I thought I was missing something but its clear now.