Composition syntax，compositionsyntax,//: reusing/

Composition syntax，compositionsyntax,//: reusing/

//: reusing/SprinklerSystem.java // Composition for code reuse.// 代码重用--组合class WaterSource {   private String s; //组合引用  WaterSource() {     System.out.println("WaterSource()");     s = "Constructed"; //初始化  }   public String toString() { return s; } }  public class SprinklerSystem {   private String valve1, valve2, valve3, valve4;   private WaterSource source = new WaterSource();  private int i;   private float f;   public String toString() {     return      "valve1 = " + valve1 + " " +       "valve2 = " + valve2 + " " +       "valve3 = " + valve3 + " " +       "valve4 = " + valve4 + "\\n" +       "i = " + i + " " + "f = " + f + " " +       "source = " + source;   }    public static void main(String[] args) {     SprinklerSystem sprinklers = new SprinklerSystem();     System.out.println(sprinklers);   } } /* Output: WaterSource() valve1 = null valve2 = null valve3 = null valve4 = null i = 0 f = 0.0 source = Constructed *///://该片段来自于http://byrx.net