迭代器模式（Iterator Pattern）提供一種方法，使得在不暴露底層實現(xiàn)的情況下，提供一種順序訪問一組對象的方法。Java中的Iterator.java迭代器接口就是該設計模式的體現(xiàn)。

一、需求舉例：

遍歷項目中使用的開發(fā)語言，{"Java", "Python", "C/C++", "C#", "Groovy", "Scala", "Shell"}，分別做相應的處理。

二、類圖：

三、代碼實例：

1.迭代接口：MyIterator

package com.lance.iterator;

public interface MyIterator {
     boolean hasNext();

     Object next();

}

2.迭代器實現(xiàn)類：CodeIterator

package com.lance.iterator;

public class CodeIterator implements MyIterator{

    public String codes[];
    int index;

    public CodeIterator(String[] codes, int index) {
        this.codes = codes;
        this.index = index;
    }

    @Override
    public boolean hasNext() {
        if(index < codes.length){
            return true;
        }
        return false;
    }

    @Override
    public Object next() {
        if(this.hasNext()){
            return codes[index++];
        }
        return null;
    }

}

3.容器父類：

package com.lance.iterator;

public interface MyContainer {
    MyIterator getIterator();
}

4.容器實現(xiàn)類：

package com.lance.iterator;

public class CodeContainer implements MyContainer {

    private MyIterator iterator;

    public CodeContainer(MyIterator iterator) {
        this.iterator = iterator;
    }

   @Override
    public MyIterator getIterator() {
        return iterator;
    }
}

5.主類：IteratorPattern

package com.lance.iterator;

public class IteratorPattern {

    public static void main(String[] args) {

        System.out.println("==========start==========");

        String codes[] = {"Java", "Python", "C/C++", "C#", "Groovy", "Scala", "Shell"};

        CodeIterator iterator = new CodeIterator(codes, 0);
        CodeContainer container = new CodeContainer(iterator);

        for(MyIterator myIterator=container.getIterator();myIterator.hasNext();) {
            System.out.println("code language : " + myIterator.next());
        }

        System.out.println("==========end==========");

    }
}

輸出結(jié)果：

==========start==========
code language : Java
code language : Python
code language : C/C++
code language : C#
code language : Groovy
code language : Scala
code language : Shell
==========end==========