学习java笔记 --- 一个实现Iterable<E>接口的小范例

public interface Iterable<T>

Iterator<T>

iterator()

iterator

Iterator<T> iterator()

String[] s ={"a","b","c"};
for (String ss : s) {
System.out.println("ss: "+ss);
}

package cn.yang.collection;

import java.util.Iterator;

/**
* 实现Iterable<E>接口的Person类
* @author yangqinjiang
*
*/
public class Person implements Iterable<Person>{

/**
* 实现Iterable接口中要求实现的方法
*/
@Override
public Iterator<Person> iterator() {
return new MyIterator();//返回一个MyIterator实例对象
}

/**
* MyIterator是内部类，实现了Iterator<E>接口的类
* 像这样的内部类，在网络上有很多这样的写法，我这里只是参考他们的写法罢了
* @author yangqinjiang
*
*/
class MyIterator implements Iterator<Person>{

/**相当于索引*/
private int index =0;
@Override
public boolean hasNext() {
//只要在调用next()后，index自加，确保index不等于person的长度
return index!=person.length;
}

@Override
public Person next() {
//使用索引来获取person数组中的某一项
return person[index++];
}

@Override
public void remove() {
//未实现这个方法
}

}

private String name;
private int age;
/**person数组，是目标操作对象*/
private Person[] person;

/**为了方便简单点，故写一个这样的构造方法*/
public Person(int size){
person=new Person[size];
for (int i = 0; i < size; i++) {
person[i]=new Person(""+i, i);
}
}

public void add(Person person){
//未实现这个方法
}

public Person(){
//未实现这个方法
}

public Person(String name,int age){
this.name=name;
this.age=age;
}

//getter
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "person [name=" + name + ", age=" + age + "]";
}

}

package cn.yang.collection;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
* 实现Iterable<E>接口的Person2类
* @author yangqinjiang
*
*/
public class Person2 implements Iterable<Person2>{

/**
* 实现Iterable接口中要求实现的方法
*/
@Override
public Iterator<Person2> iterator() {
return new MyIterator();//返回一个MyIterator实例对象
}

/**
* MyIterator是内部类，实现了Iterator<E>接口的类
* 像这样的内部类，在网络上有很多这样的写法，我这里只是参考他们的写法罢了
* @author yangqinjiang
*
*/
class MyIterator implements Iterator<Person2>{
/**相当于索引,不过不是数组索引*/
private int index =0;
@Override
public boolean hasNext() {
return index!=person.size();
}

@Override
public Person2 next() {
return person.get(index++);
}

@Override
public void remove() {

}

}

private String name;
private int age;
/**在Person2类中，person是一个数组链表*/
private List<Person2> person=new ArrayList<Person2>();

/**添加一个新Person2实例对象到person链表中*/
public void add(Person2 person2){
this.person.add(person2);
}

public Person2(){

}

public Person2(String name,int age){
this.name=name;
this.age=age;

}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "person [name=" + name + ", age=" + age + "]";
}

}

/**
* 使用"for each" 循环,可以打印数组
*/
private static void printStrings() {
System.out.println("printStrings() method running");
String[] s ={"d","f","s"};
for (String ss : s) {
System.out.println("ss: "+ss);
}
System.out.println("printStrings() method end\n");
}

System.out.println("testPerson() method running");

Person y1=new Person("1", 1);
Person y2=new Person("2", 2);
Person y3=new Person("3", 3);
Person y4=new Person("4", 4);
Person y5=new Person("5", 5);
//数组
Person y[]={y1,y2,y3,y4,y5};
for (Person ys : y) {
System.out.println(ys.getName());
}

//Iterator
System.out.println("Iterator<Person>...");
Iterator<Person> i = new Person(10).iterator();
while(i.hasNext()){
System.out.println(i.next().toString());
}

//也可以这样打印
System.out.println("other...");
Person yy=new Person(20);

for (Person ys : yy) {
System.out.println(ys.toString());
}
System.out.println("testPerson() method end\n");

System.out.println("testPerson2() method running");

Person2 p = new Person2("300", 300);
Person2 p1 = new Person2("30", 30);
Person2 p2 = new Person2("40", 40);
Person2 p3 = new Person2("50", 50);
Person2 p4 = new Person2("60", 60);
Person2 p5 = new Person2("70", 70);
p.add(p1);
p.add(p2);
p.add(p3);
p.add(p4);
p.add(p5);
//Iterator
Iterator<Person2> ii=p.iterator();
while (ii.hasNext()) {
System.out.println("Person2:  "+ii.next().toString());
}
System.out.println("testPerson2() method end\n");