001package com.ericlam.mc.eldgui;
002
003import java.util.Collection;
004import java.util.ListIterator;
005
006/**
007 * 輔助用，循環迭代器
008 * @param <E> 元素類型
009 */
010public final class CircuitIterator<E> implements ListIterator<E> {
011
012    private final E[] elements;
013    private int index = -1;
014
015    public CircuitIterator(E[] elements) {
016        this.elements = elements;
017    }
018
019    public CircuitIterator(E[] elements, int index) {
020        this.elements = elements;
021        this.index = index;
022    }
023
024    @SuppressWarnings("unchecked")
025    public CircuitIterator(Collection<E> elements) {
026        this.elements = (E[]) elements.toArray();
027    }
028
029    @SuppressWarnings("unchecked")
030    public CircuitIterator(Collection<E> elements, int index) {
031        this.elements = (E[]) elements.toArray();
032        this.index = index;
033    }
034
035    @Override
036    public boolean hasNext() {
037        return elements.length > 0;
038    }
039
040    @Override
041    public E next() {
042        if (index == elements.length - 1) {
043            index = -1;
044        }
045        return elements[++index];
046    }
047
048    @Override
049    public boolean hasPrevious() {
050        return elements.length > 0;
051    }
052
053    @Override
054    public E previous() {
055        if (index <= 0) {
056            index = elements.length;
057        }
058        return elements[--index];
059    }
060
061    @Override
062    public int nextIndex() {
063        return index + 1;
064    }
065
066    @Override
067    public int previousIndex() {
068        return index - 1;
069    }
070
071    @Override
072    public void remove() {
073        throw new UnsupportedOperationException("remove");
074    }
075
076    @Override
077    public void set(E e) {
078        throw new UnsupportedOperationException("set");
079    }
080
081    @Override
082    public void add(E e) {
083        throw new UnsupportedOperationException("add");
084    }
085}