内部类入门

内部类：在类内部又定义类，内部类作为外部类的一个field

 

/*
 * BeginInnerClass.java
 * 
 * Introduce Inner class 
 * 1. How to get Inner class in out class
 * 2. How to get Out class instance in Inner Class
 * 3. outter. new Inner() and  Outter.this
 */

package com.thinking.innerclass;

public class BeginInnerClass {

	// you can use other modifier public/protected/private
	 private class Inner {
		 
		private String name;
		
		public Inner(String name) {
			name = this.name;
		}
		
		//
		public void say(String str) {
			System.out.println("innser class:" + str);
		}
		
		//generate outter class reference
		public BeginInnerClass getOutterClass()
		{
			return BeginInnerClass.this;
		}
	}
	 
	 // the name of method same as inner class method
	 public void say(String str) {
		 System.out.println("outter class: " + str);
	 }
	
	public Inner returnInnerClass()
	{
		System.out.println(" method will return innerclass ..");
		return new Inner("zhaoyunpeng InnerClass");
	}
	
	public static void main(String[] args) {
		BeginInnerClass outter = new BeginInnerClass();
		//Reference Inner class
		BeginInnerClass.Inner inner = outter.returnInnerClass();
		inner.say("zhaoyunpeng called..");
		
//		BeginInnerClass.Inner inner2 = new BeginInnerClass.Inner("hello, world");
		BeginInnerClass outter2 = new BeginInnerClass();
		
		//Create inner class through outterClassInstance.new 
		BeginInnerClass.Inner inner2 = outter2.new Inner("hello, world");
		inner2.say(" hello called ..");

		//inner class get outter class reference through OutterClassName.this
		inner2.getOutterClass().say("zhaoyunpneg2 called ..");
	}

}