ApplicationKernelFactory.java

package kernel;

import exceptions.UnableToCreateKernelException;
import kernel.models.Kernel;
import kernel.serial_ports.PortDriver;
import org.jetbrains.annotations.Contract;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class ApplicationKernelFactory implements KernelFactory {
    private PortDriver portDriver;

    private Boolean doesKernelExist;

    private kernel.Kernel kernelInstance;

    private Boolean hasPortDriver;

    private static Logger log = LoggerFactory.getLogger
            (ApplicationKernelFactory.class);

    public ApplicationKernelFactory(){
        this.doesKernelExist = Boolean.FALSE;
        this.hasPortDriver = Boolean.FALSE;
    }

    @Override
    public void setPortDriver(PortDriver newPortDriver){
        log.debug("Setting port driver to {}", newPortDriver.toString());

        this.portDriver = newPortDriver;
        this.hasPortDriver = Boolean.TRUE;
    }

    @Override
    public kernel.Kernel getKernelInstance() throws
            UnableToCreateKernelException {
        if (!canKernelBeStarted()){
            throw new UnableToCreateKernelException("Cannot create kernel. " +
                    "Parameter missing");
        }
        if (!doesKernelExist){
            createKernel();
        }
        return this.kernelInstance;
    }

    @Contract(pure = true)
    @Override
    public Boolean canKernelBeStarted(){
        if (!hasPortDriver){
            return Boolean.FALSE;
        } else {
            return Boolean.TRUE;
        }
    }

    private void createKernel(){
        this.kernelInstance = new Kernel(
            this.portDriver
        );
        this.doesKernelExist = Boolean.TRUE;
    }
}