Any help is appreciated.

Question about the task

Factory method pattern

Java Core, Level 6, Lesson 13

Under discussion

Not sure where to put the Factory to allow it to access the enum...

1. Take a careful look at the classes you have.
2. In separate files in the common package, create JpgReader, PngReader, and BmpReader classes that implement the ImageReader interface.
3. In a separate file in the main package, create the ImageReaderFactory class with one method.
3.1. Think about what it should be called.
3.2. Think about which modifiers this method should have.
4. This method should:
4.1. For each value in ImageTypes, return the appropriate Reader. For example, for
ImageTypes.JPG, return a JpgReader;
4.2. If an invalid argument is passed, then throw an exception:
IllegalArgumentException("Unknown image type").

Requirements:

Create a JpgReader class in the common package. It must implement the ImageReader interface.
Create a PngReader class in the common package. It must implement the ImageReader interface.
Create a BmpReader class in the common package. It must implement the ImageReader interface.
Create a public class named ImageReaderFactory.
Add a public static method getImageReader with an ImageTypes parameter to the ImageReaderFactory class.
The getImageReader method must create and return a suitable Reader.
The getImageReader method must throw an IllegalArgumentException if an invalid argument is passed.

package com.codegym.task.task16.task1631; import com.codegym.task.task16.task1631.common.ImageReader; import com.codegym.task.task16.task1631.common.ImageTypes; public class Solution { public static void main(String[] args) { ImageReader reader = ImageReaderFactory.getImageReader(ImageTypes.JPG); } }

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Thomas

Level 41 , Bayreuth, Germany

17 August 2021, 06:44

You have three cases and return statements for them. That's OK. But what if none of these codepaths is chosen? Then you reach the end of your method and what? You need a return statement for that as well. Cause you do not know what to return (cause probably an illegal argument has been passed to your factory method) CG asks you to throw an IllegalArgument exception, not to catch it. That will act as a replacement for the missing return statement as it effectively kicks you out of this method and you get thrown back to the caller. You also should take care of type being null. Here they ask for it.