import javax.swing.SpinnerModel;import javax.swing.SpinnerListModel;/** * This 1.4 example is used by the various SpinnerDemos. * It implements a SpinnerListModel that works only with * an Object array and that implements cycling (the next * value and previous value are never null).  It also * lets you optionally associate a spinner model that's * linked to this one, so that when a cycle occurs the * linked spinner model is updated. * The SpinnerDemos use the CyclingSpinnerListModel for * a month spinner that (in SpinnerDemo3) is tied to the * year spinner, so that -- for example -- when the month * changes from December to January, the year increases. */public class CyclingSpinnerListModel extends SpinnerListModel {    Object firstValue, lastValue;    SpinnerModel linkedModel = null;    public CyclingSpinnerListModel(Object[] values) {        super(values);        firstValue = values[0];        lastValue = values[values.length - 1];    }    public void setLinkedModel(SpinnerModel linkedModel) {        this.linkedModel = linkedModel;    }    public Object getNextValue() {        Object value = super.getNextValue();        if (value == null) {            value = firstValue;            if (linkedModel != null) {                linkedModel.setValue(linkedModel.getNextValue());            }        }        return value;    }    public Object getPreviousValue() {        Object value = super.getPreviousValue();        if (value == null) {            value = lastValue;            if (linkedModel != null) {                linkedModel.setValue(linkedModel.getPreviousValue());            }        }        return value;    }}