设计模式之装饰模式

装饰模式适合于之前定义的某个类不够好用或者功能需要扩展，现在用一个新类继承，重写其方法。

代码演示(模拟java jdk中的FileInputStream和BufferedInputStream)

抽象类

package com.wmx.zhuangshi;

public abstract class InputStream {
    public abstract int read();

    public abstract int read(byte[] buf);
}

子类

package com.wmx.zhuangshi;

public class FileInputStream extends InputStream {

    @Override
    public int read() {
        System.out.println("低性能的进行读取");
        return 95;
    }

    @Override
    public int read(byte[] buf) {
        System.out.println("低性能的进行读取");
        buf[0] = 95;
        buf[1] = 96;
        buf[2] = 97;
        return 3;
    }
}

装饰类

package com.wmx.zhuangshi;

public class BufferedInputStream extends FileInputStream {
    private InputStream is;

    public BufferedInputStream(InputStream is) {
        this.is = is;
    }

    @Override
    public int read() {
        System.out.println("缓冲8KB字节进行高效读取");
        return is.read();
    }

    @Override
    public int read(byte[] buf) {
        System.out.println("缓冲8KB字节进行高效读取");
        return is.read(buf);
    }
}

测试类

package com.wmx.zhuangshi;

public class Test {

    public static void main(String[] args) {
        BufferedInputStream bi = new BufferedInputStream(new FileInputStream());
        bi.read();
    }

}

至此，装饰模式讲解完毕,有疑问的可以下方留言，相互学习，我是心哥说编程，致力于成为一个编程大牛编程爱好者。