Eventbus3代码分析（五）：getDefault()，register和EventBusBuilder等

public static EventBus getDefault() {
    if (defaultInstance == null) {
        synchronized (EventBus.class) {
            if (defaultInstance == null) {
                defaultInstance = new EventBus();
            }
        }
    }
    return defaultInstance;
}

EventBus(EventBusBuilder builder) {
    subscriptionsByEventType = new HashMap<>();
    typesBySubscriber = new HashMap<>();
    stickyEvents = new ConcurrentHashMap<>();
    mainThreadPoster = new HandlerPoster(this, Looper.getMainLooper(), 10);
    backgroundPoster = new BackgroundPoster(this);
    asyncPoster = new AsyncPoster(this);
    indexCount = builder.subscriberInfoIndexes != null ? builder.subscriberInfoIndexes.size() : 0;
    subscriberMethodFinder = new SubscriberMethodFinder(builder.subscriberInfoIndexes,
            builder.strictMethodVerification, builder.ignoreGeneratedIndex);
    logSubscriberExceptions = builder.logSubscriberExceptions;
    logNoSubscriberMessages = builder.logNoSubscriberMessages;
    sendSubscriberExceptionEvent = builder.sendSubscriberExceptionEvent;
    sendNoSubscriberEvent = builder.sendNoSubscriberEvent;
    throwSubscriberException = builder.throwSubscriberException;
    eventInheritance = builder.eventInheritance;
    executorService = builder.executorService;
}

private static final EventBusBuilder DEFAULT_BUILDER = new EventBusBuilder();

public class EventBusBuilder {
    private final static ExecutorService DEFAULT_EXECUTOR_SERVICE = Executors.newCachedThreadPool();

    boolean logSubscriberExceptions = true;
    boolean logNoSubscriberMessages = true;
    boolean sendSubscriberExceptionEvent = true;
    boolean sendNoSubscriberEvent = true;
    boolean throwSubscriberException;
    boolean eventInheritance = true;
    boolean ignoreGeneratedIndex;
    boolean strictMethodVerification;
    ExecutorService executorService = DEFAULT_EXECUTOR_SERVICE;
    List<Class<?>> skipMethodVerificationForClasses;
    List<SubscriberInfoIndex> subscriberInfoIndexes;

    EventBusBuilder() {
    }

    /** Default: true */
    public EventBusBuilder logSubscriberExceptions(boolean logSubscriberExceptions) {
        this.logSubscriberExceptions = logSubscriberExceptions;
        return this;
    }

    /** Default: true */
    public EventBusBuilder logNoSubscriberMessages(boolean logNoSubscriberMessages) {
        this.logNoSubscriberMessages = logNoSubscriberMessages;
        return this;
    }

    /** Default: true */
    public EventBusBuilder sendSubscriberExceptionEvent(boolean sendSubscriberExceptionEvent) {
        this.sendSubscriberExceptionEvent = sendSubscriberExceptionEvent;
        return this;
    }

    /** Default: true */
    public EventBusBuilder sendNoSubscriberEvent(boolean sendNoSubscriberEvent) {
        this.sendNoSubscriberEvent = sendNoSubscriberEvent;
        return this;
    }

    /**
     * Fails if an subscriber throws an exception (default: false).
     * <p/>
     * Tip: Use this with BuildConfig.DEBUG to let the app crash in DEBUG mode (only). This way, you won't miss
     * exceptions during development.
     */
    public EventBusBuilder throwSubscriberException(boolean throwSubscriberException) {
        this.throwSubscriberException = throwSubscriberException;
        return this;
    }

    /**
     * By default, EventBus considers the event class hierarchy (subscribers to super classes will be notified).
     * Switching this feature off will improve posting of events. For simple event classes extending Object directly,
     * we measured a speed up of 20% for event posting. For more complex event hierarchies, the speed up should be
     * >20%.
     * <p/>
     * However, keep in mind that event posting usually consumes just a small proportion of CPU time inside an app,
     * unless it is posting at high rates, e.g. hundreds/thousands of events per second.
     */
    public EventBusBuilder eventInheritance(boolean eventInheritance) {
        this.eventInheritance = eventInheritance;
        return this;
    }


    /**
     * Provide a custom thread pool to EventBus used for async and background event delivery. This is an advanced
     * setting to that can break things: ensure the given ExecutorService won't get stuck to avoid undefined behavior.
     */
    public EventBusBuilder executorService(ExecutorService executorService) {
        this.executorService = executorService;
        return this;
    }

    /**
     * Method name verification is done for methods starting with onEvent to avoid typos; using this method you can
     * exclude subscriber classes from this check. Also disables checks for method modifiers (public, not static nor
     * abstract).
     */
    public EventBusBuilder skipMethodVerificationFor(Class<?> clazz) {
        if (skipMethodVerificationForClasses == null) {
            skipMethodVerificationForClasses = new ArrayList<>();
        }
        skipMethodVerificationForClasses.add(clazz);
        return this;
    }

    /** Forces the use of reflection even if there's a generated index (default: false). */
    public EventBusBuilder ignoreGeneratedIndex(boolean ignoreGeneratedIndex) {
        this.ignoreGeneratedIndex = ignoreGeneratedIndex;
        return this;
    }

    /** Enables strict method verification (default: false). */
    public EventBusBuilder strictMethodVerification(boolean strictMethodVerification) {
        this.strictMethodVerification = strictMethodVerification;
        return this;
    }

    /** Adds an index generated by EventBus' annotation preprocessor. */
    public EventBusBuilder addIndex(SubscriberInfoIndex index) {
        if(subscriberInfoIndexes == null) {
            subscriberInfoIndexes = new ArrayList<>();
        }
        subscriberInfoIndexes.add(index);
        return this;
    }

    /**
     * Installs the default EventBus returned by {@link EventBus#getDefault()} using this builders' values. Must be
     * done only once before the first usage of the default EventBus.
     *
     * @throws EventBusException if there's already a default EventBus instance in place
     */
    public EventBus installDefaultEventBus() {
        synchronized (EventBus.class) {
            if (EventBus.defaultInstance != null) {
                throw new EventBusException("Default instance already exists." +
                        " It may be only set once before it's used the first time to ensure consistent behavior.");
            }
            EventBus.defaultInstance = build();
            return EventBus.defaultInstance;
        }
    }

    /** Builds an EventBus based on the current configuration. */
    public EventBus build() {
        return new EventBus(this);
    }

}

public void register(Object subscriber) {
    Class<?> subscriberClass = subscriber.getClass();
    List<SubscriberMethod> subscriberMethods = subscriberMethodFinder.findSubscriberMethods(subscriberClass);
    synchronized (this) {
        for (SubscriberMethod subscriberMethod : subscriberMethods) {
            subscribe(subscriber, subscriberMethod);
        }
    }
}

/** Unregisters the given subscriber from all event classes. */
public synchronized void unregister(Object subscriber) {
    List<Class<?>> subscribedTypes = typesBySubscriber.get(subscriber);
    if (subscribedTypes != null) {
        for (Class<?> eventType : subscribedTypes) {
            unsubscribeByEventType(subscriber, eventType);
        }
        typesBySubscriber.remove(subscriber);
    } else {
        Log.w(TAG, "Subscriber to unregister was not registered before: " + subscriber.getClass());
    }
}