《JAVA与模式》之装修者模式

 1 public class Zhuangxiuzhe {
 2     public static void main(String[] args) {
 3         Zhuangxiuzhe zhuangxiuzhe=new Zhuangxiuzhe();
 4         Component component=zhuangxiuzhe.new ConcreteComponent();
 5         Component decorator=zhuangxiuzhe.new ConcreteDecorator1(component);
 6         decorator.doMethod();
 7         Component decorator2=zhuangxiuzhe.new ConcreteDecorator2(decorator);
 8         decorator2.doMethod();
 9         
10     }
11 
12     interface Component {
13 
14         public void doMethod();
15 
16     }
17 
18     class ConcreteComponent implements Component {
19 
20         public void doMethod() {
21             System.out.println("一般操作");
22 
23         }
24 
25     }
26     abstract class  Decorator implements Component{
27         
28         protected Component component;
29         public Decorator(Component component){
30             this.component=component;
31         }
32             
33         
34     }
35     class ConcreteDecorator1 extends Decorator{
36 
37         public ConcreteDecorator1(Component component) {
38             super(component);
39             
40         }
41         public void test1(){
42             System.out.println("ConcreteDecorator1 额外操作");
43         }
44 
45         public void doMethod() {
46             super.component.doMethod();
47             test1();
48         }
49     }
50     class ConcreteDecorator2 extends Decorator{
51         
52         public ConcreteDecorator2(Component component) {
53             super(component);
54             
55         }
56         
57         public void doMethod() {
58             super.component.doMethod();
59             test2();
60         }
61         
62         public void test2(){
63             System.out.println("ConcreteDecorator2 额外操作");
64         }
65     }
66     
67 
68 }

1 public abstract class InputStream implements Closeable {
2 
3 
4 //实现了read等方法
5 public int read(byte b[]) throws IOException {
6     return read(b, 0, b.length);
7     }
8 
9 }

1 public
2 class FileInputStream extends InputStream{
3 
4 
5 }

 1 public
 2 class FilterInputStream extends InputStream {
 3     /**
 4      * The input stream to be filtered. 
 5      */
 6     protected volatile InputStream in;
 7 
 8 
 9 protected FilterInputStream(InputStream in) {
10     this.in = in;
11     }
12 
13  public int read() throws IOException {
14     return in.read();
15     }
16 
17 
18 }

 1 public
 2 class BufferedInputStream extends FilterInputStream {
 3 
 4 public BufferedInputStream(InputStream in) {
 5     this(in, defaultBufferSize);
 6     }
 7 
 8 //完成了设置抽象角色类的映射
 9  public BufferedInputStream(InputStream in, int size) {
10     super(in);
11         if (size <= 0) {
12             throw new IllegalArgumentException("Buffer size <= 0");
13         }
14     buf = new byte[size];
15     }
16 
17 //read方法中调用fill()
18  public synchronized int read() throws IOException {
19     if (pos >= count) {
20         fill();
21         if (pos >= count)
22         return -1;
23     }
24     return getBufIfOpen()[pos++] & 0xff;
25     }
26  private void fill() throws IOException {
27         byte[] buffer = getBufIfOpen();
28     if (markpos < 0)
29         pos = 0;        /* no mark: throw away the buffer */
30     else if (pos >= buffer.length)    /* no room left in buffer */
31         if (markpos > 0) {    /* can throw away early part of the buffer */
32         int sz = pos - markpos;
33         System.arraycopy(buffer, markpos, buffer, 0, sz);
34         pos = sz;
35         markpos = 0;
36         } else if (buffer.length >= marklimit) {
37         markpos = -1;    /* buffer got too big, invalidate mark */
38         pos = 0;    /* drop buffer contents */
39         } else {        /* grow buffer */
40         int nsz = pos * 2;
41         if (nsz > marklimit)
42             nsz = marklimit;
43         byte nbuf[] = new byte[nsz];
44         System.arraycopy(buffer, 0, nbuf, 0, pos);
45                 if (!bufUpdater.compareAndSet(this, buffer, nbuf)) {
46                     // Can‘t replace buf if there was an async close.
47                     // Note: This would need to be changed if fill()
48                     // is ever made accessible to multiple threads.
49                     // But for now, the only way CAS can fail is via close.
50                     // assert buf == null;
51                     throw new IOException("Stream closed");
52                 }
53                 buffer = nbuf;
54         }
55         count = pos;
56     int n = getInIfOpen().read(buffer, pos, buffer.length - pos);
57         if (n > 0)
58             count = n + pos;
59     }
60 
61 
62 }

1  private InputStream getInIfOpen() throws IOException {
2         InputStream input = in;
3     if (input == null)
4         throw new IOException("Stream closed");
5         return input;
6     }