public List<Invoker<T>> doList(Invocation invocation) {
    if (this.forbidden) {
        throw new RpcException(....);
    } else {
        List<Invoker<T>> invokers = null;
        Map<String, List<Invoker<T>>> localMethodInvokerMap = this.methodInvokerMap;	//獲取方法調(diào)用名和Invoker的映射表
        if (localMethodInvokerMap != null && localMethodInvokerMap.size() > 0) {
            String methodName = RpcUtils.getMethodName(invocation);
            Object[] args = RpcUtils.getArguments(invocation);
            //以下就是根據(jù)方法名和方法參數(shù)獲取可調(diào)用的Invoker
            if (args != null && args.length > 0 && args[0] != null && (args[0] instanceof String || args[0].getClass().isEnum())) {
                invokers = (List)localMethodInvokerMap.get(methodName + "." + args[0]);
            }
            if (invokers == null) {
                invokers = (List)localMethodInvokerMap.get(methodName);
            }
            if (invokers == null) {
                invokers = (List)localMethodInvokerMap.get("*");
            }
            if (invokers == null) {
                Iterator<List<Invoker<T>>> iterator = localMethodInvokerMap.values().iterator();
                if (iterator.hasNext()) {
                    invokers = (List)iterator.next();
                }
            }
        }
        return (List)(invokers == null ? new ArrayList(0) : invokers);
    }
}

public synchronized void notify(List<URL> urls) {
    List<URL> invokerUrls = new ArrayList();
    List<URL> routerUrls = new ArrayList();
    List<URL> configuratorUrls = new ArrayList();
    Iterator i$ = urls.iterator();
    while(true) {
        while(true) {
            while(i$.hasNext()) {
				//....根據(jù)urls填充上述三個(gè)列表
            }
            if (configuratorUrls != null && !configuratorUrls.isEmpty()) {
                this.configurators = toConfigurators(configuratorUrls);		//根據(jù)urls轉(zhuǎn)化為configurators配置
            }
            List localConfigurators;
            if (routerUrls != null && !routerUrls.isEmpty()) {
                localConfigurators = this.toRouters(routerUrls);
                if (localConfigurators != null) {
                    this.setRouters(localConfigurators);		//根據(jù)urls轉(zhuǎn)化為routers配置
                }
            }
            localConfigurators = this.configurators;
            this.overrideDirectoryUrl = this.directoryUrl;
            Configurator configurator;
            if (localConfigurators != null && !localConfigurators.isEmpty()) {
                for(Iterator i$ = localConfigurators.iterator(); i$.hasNext(); this.overrideDirectoryUrl = configurator.configure(this.overrideDirectoryUrl)) {
                    configurator = (Configurator)i$.next();
                }
            }
            this.refreshInvoker(invokerUrls);		//根據(jù)invokerUrls刷新invoker列表
            return;
        }
    }
}

private void refreshInvoker(List<URL> invokerUrls) {
    //如果invokerUrls只有一個(gè)URL并且協(xié)議是empty，那么清除所有invoker
    if (invokerUrls != null && invokerUrls.size() == 1 && invokerUrls.get(0) != null && "empty".equals(((URL)invokerUrls.get(0)).getProtocol())) {
        this.forbidden = true;
        this.methodInvokerMap = null;
        this.destroyAllInvokers();
    } else {
        this.forbidden = false;
        Map<String, Invoker<T>> oldUrlInvokerMap = this.urlInvokerMap;		//獲取舊的Invoker列表        
        if (invokerUrls.isEmpty() && this.cachedInvokerUrls != null) {
            invokerUrls.addAll(this.cachedInvokerUrls);
        } else {
            this.cachedInvokerUrls = new HashSet();
            this.cachedInvokerUrls.addAll(invokerUrls);
        }
        if (invokerUrls.isEmpty()) {
            return;
        }
	    //根據(jù)URL生成InvokerMap
        Map<String, Invoker<T>> newUrlInvokerMap = this.toInvokers(invokerUrls);
        //根據(jù)新的InvokerMap生成方法名和Invoker列表對(duì)應(yīng)的Map
        Map<String, List<Invoker<T>>> newMethodInvokerMap = this.toMethodInvokers(newUrlInvokerMap);
        if (newUrlInvokerMap == null || newUrlInvokerMap.size() == 0) {
            logger.error(new IllegalStateException("urls to invokers error .invokerUrls.size :" + invokerUrls.size() + ", invoker.size :0. urls :" + invokerUrls.toString()));
            return;
        }		
        this.methodInvokerMap = this.multiGroup ? this.toMergeMethodInvokerMap(newMethodInvokerMap) : newMethodInvokerMap;
        this.urlInvokerMap = newUrlInvokerMap;

        try {
            this.destroyUnusedInvokers(oldUrlInvokerMap, newUrlInvokerMap);		//銷毀無(wú)效的Invoker
        } catch (Exception var6) {
            logger.warn("destroyUnusedInvokers error. ", var6);
        }
    }
}

private final List<Invoker<T>> invokers;

protected List<Invoker<T>> doList(Invocation invocation) throws RpcException {
    return this.invokers;
}

public class FailoverCluster implements Cluster {
    public static final String NAME = "failover";
    public FailoverCluster() {
    }
    public <T> Invoker<T> join(Directory<T> directory) throws RpcException {
        return new FailoverClusterInvoker(directory);
    }
}

public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    List<Invoker<T>> copyinvokers = invokers;
    this.checkInvokers(invokers, invocation);
    //重試次數(shù)
    int len = this.getUrl().getMethodParameter(invocation.getMethodName(), "retries", 2) + 1;
    if (len <= 0) {
        len = 1;
    }
    RpcException le = null;
    List<Invoker<T>> invoked = new ArrayList(invokers.size());
    Set<String> providers = new HashSet(len);

    //根據(jù)重試次數(shù)循環(huán)調(diào)用
    for(int i = 0; i < len; ++i) {
        if (i > 0) {
            this.checkWhetherDestroyed();
            copyinvokers = this.list(invocation);
            this.checkInvokers(copyinvokers, invocation);
        }	    
        //負(fù)載均衡篩選出一個(gè)Invoker作本次調(diào)用
        Invoker<T> invoker = this.select(loadbalance, invocation, copyinvokers, invoked);
        //將使用過(guò)的Invoker保存起來(lái)，下次重試時(shí)做過(guò)濾用
        invoked.add(invoker);
        //記錄到上下文中
        RpcContext.getContext().setInvokers(invoked);
        try {
            //發(fā)起調(diào)用
            Result result = invoker.invoke(invocation);
            if (le != null && logger.isWarnEnabled()) {
                logger.warn("....");
            }
			
            Result var12 = result;
            return var12;
        } catch (RpcException var17) {	//catch異常 繼續(xù)下次循環(huán)重試
            if (var17.isBiz()) {
                throw var17;
            }

            le = var17;
        } catch (Throwable var18) {
            le = new RpcException(var18.getMessage(), var18);
        } finally {
            providers.add(invoker.getUrl().getAddress());
        }
    }

    throw new RpcException(....);
}

public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    this.checkInvokers(invokers, invocation);
    Invoker invoker = this.select(loadbalance, invocation, invokers, (List)null);	//負(fù)載均衡選擇Invoker

    try {
        return invoker.invoke(invocation);		//發(fā)起遠(yuǎn)程調(diào)用
    } catch (Throwable var6) {	//失敗調(diào)用直接將錯(cuò)誤拋出
        if (var6 instanceof RpcException && ((RpcException)var6).isBiz()) {
            throw (RpcException)var6;
        } else {
            throw new RpcException(....);
        }
    }
}

public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    try {
        this.checkInvokers(invokers, invocation);
        //負(fù)載均衡選出Invoker后直接進(jìn)行調(diào)用
        Invoker<T> invoker = this.select(loadbalance, invocation, invokers, (List)null);	
        return invoker.invoke(invocation);
    } catch (Throwable var5) {	//調(diào)用錯(cuò)誤只是打印日志
        logger.error("Failsafe ignore exception: " + var5.getMessage(), var5);
        return new RpcResult();
    }
}

protected Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    try {
        this.checkInvokers(invokers, invocation);
        //負(fù)載均衡選出Invoker
        Invoker<T> invoker = this.select(loadbalance, invocation, invokers, (List)null);
        //執(zhí)行調(diào)用，執(zhí)行成功返回調(diào)用結(jié)果
        return invoker.invoke(invocation);
    } catch (Throwable var5) {
        //調(diào)用失敗
        logger.error("....");
        //記錄下本次失敗調(diào)用
        this.addFailed(invocation, this);
        //返回空結(jié)果
        return new RpcResult();
    }
}
private void addFailed(Invocation invocation, AbstractClusterInvoker<?> router) {
    if (this.retryFuture == null) {
        synchronized(this) {
            //如果未創(chuàng)建重試本次調(diào)用的定時(shí)任務(wù)
            if (this.retryFuture == null) {
                //創(chuàng)建定時(shí)任務(wù)
                this.retryFuture = this.scheduledExecutorService.scheduleWithFixedDelay(new Runnable() {
                    public void run() {
                        try {
                            //定時(shí)進(jìn)行重試
                            FailbackClusterInvoker.this.retryFailed();
                        } catch (Throwable var2) {
                            FailbackClusterInvoker.logger.error("....", var2);
                        }

                    }
                }, 5000L, 5000L, TimeUnit.MILLISECONDS);
            }
        }
    }	
    //將invocation和router存入map
    this.failed.put(invocation, router);
}
void retryFailed() {
    if (this.failed.size() != 0) {
        Iterator i$ = (new HashMap(this.failed)).entrySet().iterator();
        while(i$.hasNext()) {
            Entry<Invocation, AbstractClusterInvoker<?>> entry = (Entry)i$.next();
            Invocation invocation = (Invocation)entry.getKey();
            Invoker invoker = (Invoker)entry.getValue();
            try {
                //進(jìn)行重試調(diào)用
                invoker.invoke(invocation);
                //調(diào)用成功未產(chǎn)生異常則移除本次失敗調(diào)用的記錄，銷毀定時(shí)任務(wù)
                this.failed.remove(invocation);
            } catch (Throwable var6) {
                logger.error("....", var6);
            }
        }

    }
}

public Result doInvoke(final Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    Result var19;
    try {
        this.checkInvokers(invokers, invocation);
        int forks = this.getUrl().getParameter("forks", 2);
        int timeout = this.getUrl().getParameter("timeout", 1000);        
        final Object selected;
        if (forks > 0 && forks < invokers.size()) {
            selected = new ArrayList();

            for(int i = 0; i < forks; ++i) {
                Invoker<T> invoker = this.select(loadbalance, invocation, invokers, (List)selected);
                if (!((List)selected).contains(invoker)) {
                    //選擇好的Invoker放入這個(gè)selected列表
                    ((List)selected).add(invoker);
                }
            }
        } else {
            selected = invokers;
        }
        RpcContext.getContext().setInvokers((List)selected);
        final AtomicInteger count = new AtomicInteger();
        //阻塞隊(duì)列
        final BlockingQueue<Object> ref = new LinkedBlockingQueue();
        Iterator i$ = ((List)selected).iterator();
        while(i$.hasNext()) {
            final Invoker<T> invoker = (Invoker)i$.next();
            this.executor.execute(new Runnable() {
                public void run() {
                    try {
                        Result result = invoker.invoke(invocation);
                        ref.offer(result);
                    } catch (Throwable var3) {
                        int value = count.incrementAndGet();
                        if (value >= ((List)selected).size()) {		//等待所有調(diào)用都產(chǎn)生異常才入隊(duì)
                            ref.offer(var3);
                        }
                    }

                }
            });
        }
        try {
            //阻塞獲取結(jié)果
            Object ret = ref.poll((long)timeout, TimeUnit.MILLISECONDS);
            if (ret instanceof Throwable) {
                Throwable e = (Throwable)ret;
                throw new RpcException(....);
            }
            var19 = (Result)ret;
        } catch (InterruptedException var14) {
            throw new RpcException(....);
        }
    } finally {
        RpcContext.getContext().clearAttachments();
    }
    return var19;
}

public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
    this.checkInvokers(invokers, invocation);
    RpcContext.getContext().setInvokers(invokers);
    RpcException exception = null;
    Result result = null;
    Iterator i$ = invokers.iterator();
    while(i$.hasNext()) {
        Invoker invoker = (Invoker)i$.next();
        try {
            result = invoker.invoke(invocation);
        } catch (RpcException var9) {
            exception = var9;
            logger.warn(var9.getMessage(), var9);
        } catch (Throwable var10) {
            exception = new RpcException(var10.getMessage(), var10);
            logger.warn(var10.getMessage(), var10);
        }
    }	
    //如果調(diào)用過(guò)程中發(fā)生過(guò)錯(cuò)誤 拋出異常
    if (exception != null) {
        throw exception;
    } else {
        //返回調(diào)用結(jié)果
        return result;
    }
}

public class AvailableCluster implements Cluster {
    public static final String NAME = "available";

    public AvailableCluster() {
    }   
    public <T> Invoker<T> join(Directory<T> directory) throws RpcException {
        return new AbstractClusterInvoker<T>(directory) {
            public Result doInvoke(Invocation invocation, List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
                Iterator i$ = invokers.iterator();

                Invoker invoker;
                do {		//循環(huán)判斷：哪個(gè)invoker能用就調(diào)用哪個(gè)
                    if (!i$.hasNext()) {
                        throw new RpcException("No provider available in " + invokers);
                    }

                    invoker = (Invoker)i$.next();
                } while(!invoker.isAvailable());

                return invoker.invoke(invocation);
            }
        };
    }
}

public <T> Invoker<T> select(List<Invoker<T>> invokers, URL url, Invocation invocation) {
        if (invokers != null && !invokers.isEmpty()) {
            //子類實(shí)現(xiàn)
            return invokers.size() == 1 ? (Invoker)invokers.get(0) : this.doSelect(invokers, url, invocation);
        } else {
            return null;
        }
}
protected abstract <T> Invoker<T> doSelect(List<Invoker<T>> var1, URL var2, Invocation var3);

protected int getWeight(Invoker<?> invoker, Invocation invocation) {
    int weight = invoker.getUrl().getMethodParameter(invocation.getMethodName(), "weight", 100);	//獲得權(quán)重
    if (weight > 0) {
        long timestamp = invoker.getUrl().getParameter("remote.timestamp", 0L);		//啟動(dòng)時(shí)間
        if (timestamp > 0L) {
            int uptime = (int)(System.currentTimeMillis() - timestamp);   	//計(jì)算已啟動(dòng)時(shí)長(zhǎng)
            int warmup = invoker.getUrl().getParameter("warmup", 600000);
            if (uptime > 0 && uptime < warmup) {
                weight = calculateWarmupWeight(uptime, warmup, weight);		//降權(quán)
            }
        }
    }
    return weight;
}

protected <T> Invoker<T> doSelect(List<Invoker<T>> invokers, URL url, Invocation invocation) {
    int length = invokers.size();		//Invoker個(gè)數(shù)
    int totalWeight = 0;		//總權(quán)重
    boolean sameWeight = true;     //權(quán)重是否相同
    int offset;			
    int i;
    for(offset = 0; offset < length; ++offset) {	
        i = this.getWeight((Invoker)invokers.get(offset), invocation);		//得到權(quán)重
        totalWeight += i;	  //計(jì)算總權(quán)重
        //是否權(quán)重都相同
        if (sameWeight && offset > 0 && i != this.getWeight((Invoker)invokers.get(offset - 1), invocation)) {
            sameWeight = false;		
        }
    }
    if (totalWeight > 0 && !sameWeight) {
        offset = this.random.nextInt(totalWeight);		//獲得隨機(jī)偏移量		
       	//判斷偏移量落在哪個(gè)片段上
        for(i = 0; i < length; ++i) {
            offset -= this.getWeight((Invoker)invokers.get(i), invocation);
            if (offset < 0) {
                return (Invoker)invokers.get(i);		
            }
        }
    }	
    return (Invoker)invokers.get(this.random.nextInt(length));
}