java - 关于 java 上下文的委托(delegate)示例

Question

什么是 Java 中的委托(delegate)？谁能给我一个合适的例子？

Answer 1

这就是委托(delegate)——就像在现实世界中一样:

public interface Worker() {
  public Result work();
}

public class Secretary() implements Worker {

   public Result work() {
     Result myResult = new Result();
     return myResult;
   }    
}

public class Boss() implements Worker {

   private Secretary secretary;

   public Result work() {
     if (secretary == null) {
        // no secretary - nothing get's done
        return null;
     }
     return secretary.work();
   }

   public void setSecretary(Secretary secretary) {
       this.secretary = secretary;
   }
}

(添加 Worker 接口(interface)以更接近 Delegator 模式)