Java中的链式调用

MsgInfo msgInfo = new MsgInfo();
        msgInfo.setOwnerId("100011002")
                .setRelatedId("1000110003")
                .setBody("hello 链式调用")
                .setType(MsgInfo.Type.TEXT)
                .setDirect(MsgInfo.Direct.SEND)
                .setStatus(MsgInfo.Status.SENDING)
                .setTime(System.currentTimeMillis());

    有时开发中我们会看到这种这种写法，这是如何实现的呢，代码如下：

    public class Persion {
    private int id;
    private String name;
    private String phoneNumber;
    private String address;
    public  Persion() {
    }
    public Persion setId(int id) { 
        this.id = id;
        return this;
    }
    public Persion setName(String name) {
        this.name = name;
        return this;
    }
    public Persion setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
        return this;
    }
    public Persion setAddress(String address) {
        this.address = address;
        return this;
    }
    public Persion printId() {
        System.out.println(this.id);
        return this;
    }
    public Persion printName() {
        System.out.println(this.name);
        return this;
    }
    public Persion printPhoneNumber() {
        System.out.println(this.phoneNumber);
        return this;
    }
    public Persion printAddress() {
        System.out.println(this.address);
        return this;
    }
}

JavaScript中可以这样写

function Dog(){
    this.run= function(){
      alert("The dog is running....");
      return this;//返回当前对象 Dog
    };
    this.eat= function(){
      alert("After running the dog is eatting....");
      return this;//返回当前对象 Dog
 
    };
    this.sleep= function(){
      alert("After eatting the dog is running....");
      return this;//返回当前对象 Dog
 
    };
  }

本质上是在set值得时候返回this
这种写法经常与Builder设计模式一起使用，在Android中有大量实现。当然在用这种方式不利于代码调试。