EventBus2 2原始碼分析

由於我們專案使用了eventbus2，所以檢視一下原始碼，了解一下原理

// 訂閱方法，按event型別歸類

private
final map, copyonwritearraylist> subscriptionsbyeventtype;
// 快取已經註冊的物件，可防止物件重複註冊
private
final map>> typesbysubscriber;
// 快取粘性時間，用於使用registersticky方法註冊後立刻執行事件
private
final map, object> stickyevents;

private

synchronized
void
register(classloader loader, string stuckclassname, object subscriber, string methodname, boolean sticky, int priority) 
listsubscribermethods = subscribermethodfinder.findsubscribermethods(loader, stuckclassname, subscriber.getclass(),
methodname);
for (subscribermethod subscribermethod : subscribermethods) 
}public
synchronized
boolean
isregistered(object subscriber)

listfindsubscribermethods(classloader loader, string stuckclassname, class<?> subscriberclass, string eventmethodname) 

if (subscribermethods != null) 
subscribermethods = new arraylist();
class<?> clazz = loadclass(loader, subscriberclass);
hashset eventtypesfound = new hashset();
stringbuilder methodkeybuilder = new stringbuilder();
while (clazz != null) 
// starting with eventbus 2.2 we enforced methods to be public (might change with annotations again)
method methods = clazz.getdeclaredmethods();
for (method method : methods)  else
if (modifierstring.equals("mainthread"))  else
if (modifierstring.equals("backgroundthread"))  else
if (modifierstring.equals("async"))  else  else 
}class<?> eventtype = parametertypes[0];
methodkeybuilder.setlength(0);
//拼接key，方法名字+">"+引數類名
string methodkey = methodkeybuilder.tostring();
if (eventtypesfound.add(methodkey)) 
}} else
if (!skipmethodverificationforclasses.containskey(clazz)) }}
//對比查詢類名，相同跳出方法
if (name.equals(stuckclassname)) 
//搜尋父類的方法
clazz = loadclass(loader, clazz.getsuperclass());
}if (subscribermethods.isempty())  else 
return subscribermethods;
}}

// must be called in synchronized block

private
void
subscribe(object subscriber, subscribermethod subscribermethod, boolean sticky, int priority)  else }}
// starting with eventbus 2.2 we enforced methods to be public (might change with annotations again)
// subscribermethod.method.setaccessible(true);
int size = subscriptions.size();
for (int i = 0; i <= size; i++) 
}list> subscribedevents = typesbysubscriber.get(subscriber);
if (subscribedevents == null) 
subscribedevents.add(eventtype);
//執行粘性事件
if (sticky) 
if (stickyevent != null) 
}}

public

void
post(object event)  else 
try 
} finally }}
//獲取event監聽者，分發事件
private
void
postsingleevent(object event, postingthreadstate postingstate) throws error 
if (subscriptions != null && !subscriptions.isempty())  finally 
if (aborted) 
}subscriptionfound = true;}}
if (!subscriptionfound) }}
// 執行訂閱的方法
private
void
posttosubscription(subscription subscription, object event, boolean ismainthread)  else 
break;
case threadmode.backgroundthread:
if (ismainthread)  else 
break;
case threadmode.async:
//static executorservice executorservice = executors.newfixedthreadpool(15);
// 非同步併發方法，通過固定執行緒池切換到子執行緒執行，最多可以執行15個任務
asyncposter.enqueue(subscription, event);
break;
default:
throw
new illegalstateexception("unknown thread mode: " + subscription.subscribermethod.threadmode);
}}

public

void
poststicky(object event) 
post(event);
}

public boolean removestickyevent(object event)  else }}

public synchronized void

unregister(object subscriber) 
//移除註冊的物件
typesbysubscriber.remove(subscriber);
} else 
private
void
unubscribebyeventtype(object subscriber, class<?> eventtype) }}
}

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