TEST

gistfile1.java

Main{
    DataTypePowerSwitch.PSItem item;
    SourcePowerSwitch a = new SourcePowerSwitch();
    a.addItem(item);
}

public class SourcePowerSwitch implements DataTypePowerSwitch, PSData {
    public void addItem(DataTypePowerSwitch.PSItem item) {
        addItem a = new addItem();
        a.addItem(item);
    }
}

public class addItem extends SourcePowerSwitch implements PSData{
    public void addItem(DataTypePowerSwitch.PSItem item) {
    }
}