Here is an example of a class extending AppenderAttachableImpl in Logback:

import ch.qos.logback.core.spi.AppenderAttachable;
import ch.qos.logback.core.spi.AppenderAttachableImpl;

public class MyAppenderAttachable<E> extends AppenderAttachableImpl<E> {

    @Override
    public void addAppender(E newAppender) {
        // add appender logic
        super.addAppender(newAppender);
    }

    @Override
    public int appendLoopOnAppenders(E event) {
        // append loop on appenders logic
        return super.appendLoopOnAppenders(event);
    }

    @Override
    public boolean detachAppender(E appender) {
        // detach appender logic
        return super.detachAppender(appender);
    }

    @Override
    public boolean detachAppender(String name) {
        // detach appender by name logic
        return super.detachAppender(name);
    }
}

This class is an example of a custom Appender Attachable in Logback, which is used to attach and detach appenders to a logger or other logging component. It extends AppenderAttachableImpl, which is an implementation of the AppenderAttachable interface.

The addAppender method is overridden to define the logic for adding an appender to the logging component. The appendLoopOnAppenders method is overridden to define the logic for looping through the appenders and appending the event to each of them. The detachAppender method is overridden to define the logic for detaching an appender from the logging component. The detachAppender by name method is overridden to define the logic for detaching an appender from the logging component by its name.

It is important to note that this class is extending AppenderAttachableImpl which is an implementation of the AppenderAttachable interface, which provides the ability to attach and detach appenders to a logger or other logging component. AppenderAttachableImpl is a base class for implementing the AppenderAttachable interface and it should be used as a base for creating custom appender attachable implementations.