Month: August 2020

I am developing an android app to process jpg exif meta data in a workflow.

The Workflow class is implemented platform independant (i.e. code runs on android and on j2se).

The Workflow contains and calls protected virtual methods that do nothing for android specific .functions (i.e save changes to android media database)

package de.k3b.media;

// platform independant
public class Workflow {
    public void processPhoto(...) {
        ...
        saveChangesToMediaDatabase(....);
        ...
    }
    
    protected void saveChangesToMediaDatabase(...) {    
        // to nothing in platform independant version
    }
}

I also have a android platform specific sub class that implements the platform specific code

package de.k3b.android.media;

// android platform dependant
public class AndroidWorkflow extends Workflow {
    @Override
    protected void saveChangesToMediaDatabase(...) {    
        ... do something with android media database
    }
}

I can use Workflow.processPhoto(...) in non-android j2se apps and in automated unit or integration tests
and i can use AndroidWorkflow.processPhoto(...) in my android app

My question: Is this an established pattern and is there a name for this pattern?
My current pattern name “Platform independant class with Hooks” and “Platform specific Hook implementation”.

I hope to find a better (??established??) name for this pattern.

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Remarks:

One established pattern to have platformindependat code is by using a Facade pattern.

Example: I use a FileFacade with a j2se implementation based on java.io.File and AndroidFileFacade which is based on android specific DocumentFile.

Although the goal of platform independance is the same the way how this is achieved is different.