EventBus阅读源码（2）-SubscriberMethod

如果说为什么选择源码的阅读顺序，这个其实没有什么跟据，我写在这里的顺序绝对不是我阅读的顺序，阅读的时候都是交叉的，很难说选的顺序正好是循序渐进的。而且一般都是找到一个入口来进行的，例如从EventBus类开始。

这适合我们开始的时候通览代码，当对代码有了一个大致的了解之后，如果要细细的分析，则要从根部着手。

这篇文章看

SubscriberMethod

该类只是基于了ThreadMode，没有基于其它的类，所以我们可以放心阅读。

Subscriber的意思是订阅者。顾名思义，就是只订阅者方法。猜想一下是不是像我们注册的方法呢（例如onMainThread(Event event)）。

源码：

/*
 * Copyright (C) 2012-2016 Markus Junginger, greenrobot (http://greenrobot.org)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.greenrobot.eventbus;

import java.lang.reflect.Method;

/** Used internally by EventBus and generated subscriber indexes. */
public class SubscriberMethod {
    final Method method;//方法
    final ThreadMode threadMode;//该方法的模式，即在什么线程中执行
    final Class eventType;//事件类型，就是我们注册方式的时候的参数类型
    final int priority;//优先级
    final boolean sticky;//是否粘性的
    /** Used for efficient comparison */
    String methodString;//方法的字符串描述，主要用于比较

    public SubscriberMethod(Method method, Class eventType, ThreadMode threadMode, int priority, boolean sticky) {
        this.method = method;
        this.threadMode = threadMode;
        this.eventType = eventType;
        this.priority = priority;
        this.sticky = sticky;
    }

    @Override
    public boolean equals(Object other) {//比较两个方法是否相等，即是否是一个方法
        if (other == this) {
            return true;
        } else if (other instanceof SubscriberMethod) {
            checkMethodString();
            SubscriberMethod otherSubscriberMethod = (SubscriberMethod)other;
            otherSubscriberMethod.checkMethodString();
            // Don't use method.equals because of http://code.google.com/p/android/issues/detail?id=7811#c6
            return methodString.equals(otherSubscriberMethod.methodString);
        } else {
            return false;
        }
    }

    private synchronized void checkMethodString() {//计算方法的字符串描述
        if (methodString == null) {
            // Method.toString has more overhead, just take relevant parts of the method
            StringBuilder builder = new StringBuilder(64);
            builder.append(method.getDeclaringClass().getName());
            builder.append('#').append(method.getName());
            builder.append('(').append(eventType.getName());
            methodString = builder.toString();
        }
    }

    @Override
    public int hashCode() {
        return method.hashCode();
    }
}

代码不多。

容易理解。

不做过多啰嗦。