concreteiterator.java

来自「《Java与模式》一书的源代码」· Java 代码 · 共 39 行

package com.javapatterns.iterator.whitebox;

public class ConcreteIterator implements Iterator
{
    private ConcreteAggregate agg;
    private int index = 0;
    private int size = 0;

    public ConcreteIterator(ConcreteAggregate agg)
    {
        this.agg = agg;
        size = agg.size();
        index = 0;
    }

    public void first()
    {
        index = 0;
    }

    public void next()
    {
        if (index < size)
        {
            index++;
        }
    }

    public boolean isDone()
    {
        return (index >= size);
    }

    public Object currentItem()
    {
        return agg.getElement(index);
    }
}