java - 使用函数引用等将代码转换为 Java 8 方法

Question

我有一个类如下:

public class MyClass {  
  interface MyBuilder {  
      List<MyObject> initObjects(String quantifier);  
  }  

  private static class Builder1 implements MyBuilder {  
      @Override  
      List<MyObject> initObjects(String quantifier) {  
        // code omitted for clarity

      }  
  }  

  private static class Builder2 implements MyBuilder {  
      @Override  
      List<MyObject> initObjects(String quantifier) {  
        // code omitted for clarity

      }  
  }  

  private static HashMap<String, MyBuilder> builders = ….;  
  static {  
     builders.put("type1", new Builder1());  
     builders.put("type2", new Builder2());  
  }  
  //etc  

有没有办法通过 Java8 将此代码转换为函数引用并以某种方式使其“更短”？
我想练习一些带有函数引用等的 Java8 习惯用法

Answer 1

因为MyBuilder是一个功能接口(interface)(具有单个方法的接口(interface))，您可以内联 Builder1 的实现和Builder2 :

static {  
  builders.put("type1", quantifier -> /*code here*/);  
  builders.put("type2", quantifier -> /*code here*/);  
}

此外，您的MyBuilder接口(interface)相当于 java.util.function.Function<String, List<MyObject>> :

private static HashMap<String, Function<String, List<MyObject>> builders = ….;