/**
 * 書的抽象構(gòu)件
 * @author tcy
 * @Date 10-08-2022
 */
public abstract class ComponentBook {

    /**
     * 借書
     */
    public abstract void borrowBook();

    /**
     * 買書
     */
    public abstract void buyBook();

}

/**
 * 書的具體構(gòu)件
 * @author tcy
 * @Date 10-08-2022
 */
public class ConcreteComponentBook extends ComponentBook{
    @Override
    public void borrowBook() {
        System.out.println("老王的書借出去...");

    }

    @Override
    public void buyBook() {
        System.out.println("老王的書買回來...");

    }
}

/**
 * 書的裝飾者
 * @author tcy
 * @Date 10-08-2022
 */
public class DecoratorBook extends ComponentBook{

    private ComponentBook componentBook;

    DecoratorBook(ComponentBook componentBook){
        this.componentBook=componentBook;
    }

    @Override
    public void borrowBook() {
        this.componentBook.borrowBook();
    }

    @Override
    public void buyBook() {
        this.componentBook.buyBook();
    }
}

/**
 * 子類里寫了并且使用了無參的構(gòu)造方法但是它的父類（祖先）中卻至少有一個是沒有無參構(gòu)造方法的
 * @author tcy
 * @Date 10-08-2022
 */
public class ConcreteDecoratorBook1 extends DecoratorBook{

    ConcreteDecoratorBook1(ComponentBook componentBook) {
        super(componentBook);
    }

    public void cleanRoom(){
        System.out.println("打掃書房...");
    }

    public void shutRoom(){
        System.out.println("關(guān)閉書房...");
    }

    public void recordBook(){
        System.out.println("記錄借出記錄...");
    }

    public void returnBook(){
        System.out.println("收到借出去的書...");
    }

    @Override
    public void buyBook() {
        this.cleanRoom();
        super.buyBook();
        this.shutRoom();
        System.out.println("----------------------------");
    }

    @Override
    public void borrowBook() {
        this.recordBook();
        super.borrowBook();
        this.returnBook();
        System.out.println("----------------------------");
    }
}

/**
 * @author tcy
 * @Date 09-08-2022
 */
public class  {
    public static void main(String[] args) {

        ComponentBook componentBook=new ConcreteComponentBook();
        componentBook=new ConcreteDecoratorBook1(componentBook);

        componentBook.borrowBook();

        componentBook.buyBook();
    }
}

FileInputStream fileInputStream = new FileInputStream(filePath); 
BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

public class BufferedInputStream extends FilterInputStream {

    private static int DEFAULT_BUFFER_SIZE = 8192;

    protected int marklimit;

    public BufferedInputStream(InputStream in) {
        this(in, DEFAULT_BUFFER_SIZE);
    }

  	...
    //增強的方法
    private void fill() throws IOException {
        byte[] buffer = getBufIfOpen();
        if (markpos < 0)
            pos = 0;            /* no mark: throw away the buffer */
        else if (pos >= buffer.length)  /* no room left in buffer */
            if (markpos > 0) {  /* can throw away early part of the buffer */
                int sz = pos - markpos;
                System.arraycopy(buffer, markpos, buffer, 0, sz);
                pos = sz;
                markpos = 0;
            } else if (buffer.length >= marklimit) {
                markpos = -1;   /* buffer got too big, invalidate mark */
                pos = 0;        /* drop buffer contents */
            } else if (buffer.length >= MAX_BUFFER_SIZE) {
                throw new OutOfMemoryError("Required array size too large");
            } else {            /* grow buffer */
                int nsz = (pos <= MAX_BUFFER_SIZE - pos) ?
                        pos * 2 : MAX_BUFFER_SIZE;
                if (nsz > marklimit)
                    nsz = marklimit;
                byte nbuf[] = new byte[nsz];
                System.arraycopy(buffer, 0, nbuf, 0, pos);
                if (!bufUpdater.compareAndSet(this, buffer, nbuf)) {
                    // Can't replace buf if there was an async close.
                    // Note: This would need to be changed if fill()
                    // is ever made accessible to multiple threads.
                    // But for now, the only way CAS can fail is via close.
                    // assert buf == null;
                    throw new IOException("Stream closed");
                }
                buffer = nbuf;
            }
        count = pos;
        int n = getInIfOpen().read(buffer, pos, buffer.length - pos);
        if (n > 0)
            count = n + pos;
    }

   ...

public class TransactionAwareCacheDecorator implements Cache {

	//抽象構(gòu)件
   private final Cache targetCache;

   /**
    * Create a new TransactionAwareCache for the given target Cache.
    * @param targetCache the target Cache to decorate
    */
   public TransactionAwareCacheDecorator(Cache targetCache) {
      Assert.notNull(targetCache, "Target Cache must not be null");
      this.targetCache = targetCache;
   }

   /**直接調(diào)用未增強
    * Return the target Cache that this Cache should delegate to.
    */
   public Cache getTargetCache() {
      return this.targetCache;
   }

	//直接調(diào)用未增強
   @Override
   public String getName() {
      return this.targetCache.getName();
   }

//直接調(diào)用未增強
   @Override
   public Object getNativeCache() {
      return this.targetCache.getNativeCache();
   }

//直接調(diào)用未增強
   @Override
   @Nullable
   public ValueWrapper get(Object key) {
      return this.targetCache.get(key);
   }

//直接調(diào)用未增強
   @Override
   public <T> T get(Object key, @Nullable Class<T> type) {
      return this.targetCache.get(key, type);
   }

//直接調(diào)用未增強
   @Override
   @Nullable
   public <T> T get(Object key, Callable<T> valueLoader) {
      return this.targetCache.get(key, valueLoader);
   }

//先進行判斷確定是否需要增強
   @Override
   public void put(final Object key, @Nullable final Object value) {
      if (TransactionSynchronizationManager.isSynchronizationActive()) {
         TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
            @Override
            public void afterCommit() {
               TransactionAwareCacheDecorator.this.targetCache.put(key, value);
            }
         });
      }
      else {
         this.targetCache.put(key, value);
      }
   }
}

  @Override
   public void put(final Object key, @Nullable final Object value) {
      if (TransactionSynchronizationManager.isSynchronizationActive()) {
         TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
            @Override
            public void afterCommit() {
               TransactionAwareCacheDecorator.this.targetCache.put(key, value);
            }
         });
      }
      else {
         this.targetCache.put(key, value);
      }
   }

public class CachingExecutor implements Executor {
    //持有組件對象
  private Executor delegate;
  private TransactionalCacheManager tcm = new TransactionalCacheManager();
    //構(gòu)造方法，傳入組件對象
  public CachingExecutor(Executor delegate) {
    this.delegate = delegate;
    delegate.setExecutorWrapper(this);
  }
  @Override
  public int update(MappedStatement ms, Object parameterObject) throws SQLException {
      //轉(zhuǎn)發(fā)請求給組件對象，可以在轉(zhuǎn)發(fā)前后執(zhí)行一些附加動作
    flushCacheIfRequired(ms);
    return delegate.update(ms, parameterObject);
  }
  //...
 }