繼續,現在介紹一下中介者模式呢,中介?想必大傢都知道吧?房屋中介,職業中介等等,我們繼續我們的《西遊記》,話說唐僧被妖怪偷偷抓走瞭,三個徒弟都不知道被誰抓走的,怎麼辦呢?唐僧就用他的三寸不爛之舌說服瞭一個小妖,讓他去通知他的徒弟們來救他,小妖就去通知瞭,徒弟們知道瞭就叫小妖回去跟唐僧說,讓唐僧安心,然後徒弟們自會去救他,這裡唐僧沒有直接跟他的徒弟們交流,都是通過小妖來轉達的,這裡這個小妖就是中介者,這就是典型的中介都模式,我們首先實現小妖的代碼:
[java] view plaincopyprint?public class Monster {
Person person;
public Monster() {
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
public String getMessage() {
return person.getMessage();
}
public void setMessage(String message) {
person.setMessage(message);
}
}
public class Monster {
Person person;
public Monster() {
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
public String getMessage() {
return person.getMessage();
}
public void setMessage(String message) {
person.setMessage(message);
}
}
這裡我們定義瞭小妖可以幹的事,例可以把消息轉達給誰,可以轉達一些什麼消息,當然也可以對所要轉達的消息進行包裝,這裡就涉及到“包裝模式”瞭,我們放後面說:接下來再看一下唐僧的實現代碼:[java] view plaincopyprint?<pre name="code" class="java">public class Tangseng {
private Monster monster;
public Tangseng() {
monster = new Monster();
}
public void sendMessage(Person person, String message) {
monster.setPerson(person);
monster.setMessage(message);
}
public String getMessage() {
return monster.getMessage();
}
}
<pre name="code" class="java">public class Tangseng {
private Monster monster;
public Tangseng() {
monster = new Monster();
}
public void sendMessage(Person person, String message) {
monster.setPerson(person);
monster.setMessage(message);
}
public String getMessage() {
return monster.getMessage();
}
}這裡唐僧隻給小妖傳消息,當然也會指明這消息是給誰的,例:唐僧會說:幫我告訴悟空,叫他趕緊來救我,這裡的Person就是指的悟空。我們再來看一下Person接口呢,定義瞭每個徒弟要做的事,例如收到消息,返回消息
[java] view plaincopyprint?<pre name="code" class="java">public interface Person {
public void setMessage(String message);
public String getMessage();
}
<pre name="code" class="java">public interface Person {
public void setMessage(String message);
public String getMessage();
}
好,接下來就是具體的實現類瞭,悟空:
[java] view plaincopyprint?<pre name="code" class="java">public class Wukong implements Person {
private String name;
private String message;
public Wukong() {
this.name = "孫悟空";
}
@Override
public void setMessage(String message) {
this.message = message;
}
@Override
public String getMessage() {
return name + "收到" + message;
}
}
<pre name="code" class="java">public class Wukong implements Person {
private String name;
private String message;
public Wukong() {
this.name = "孫悟空";
}
@Override
public void setMessage(String message) {
this.message = message;
}
@Override
public String getMessage() {
return name + "收到" + message;
}
}
悟空能收到師傅發來的消息,並返回給師傅,他知道師傅被抓瞭,會盡快去救他。
最後就是Android中的實現瞭
[java] view plaincopyprint?public class XiyoujiActivity extends Activity {
private ListView listView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView) findViewById(R.id.listView1);
ArrayList<String> lists = new ArrayList<String>();
Tangseng tangseng = new Tangseng();
tangseng.sendMessage(new Wukong(), "唐僧發出'悟空救我!'的消息");
lists.add(tangseng.getMessage());
tangseng.sendMessage(new Bajie(), "唐僧發出'八戒救我!'的消息");
lists.add(tangseng.getMessage());
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, lists);
listView.setAdapter(adapter);
}
}
public class XiyoujiActivity extends Activity {
private ListView listView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView) findViewById(R.id.listView1);
ArrayList<String> lists = new ArrayList<String>();
Tangseng tangseng = new Tangseng();
tangseng.sendMessage(new Wukong(), "唐僧發出'悟空救我!'的消息");
lists.add(tangseng.getMessage());
tangseng.sendMessage(new Bajie(), "唐僧發出'八戒救我!'的消息");
lists.add(tangseng.getMessage());
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, lists);
listView.setAdapter(adapter);
}
}看,唐僧會讓小妖給悟空帶話:讓悟空去救他。最後就是看一下顯示效果:
OK,這裡中介都模式也講完瞭,其實還可以再深入一點就是唐僧隻發出求救信息,然後小妖看到誰就通知誰,這裡我們下一章再講解,謝謝。
摘自 kangkangz4的專欄