Update the latest code

README.md

@@ -57,7 +57,7 @@ public interface GreetingService {
 }
 ```
 
-*See [api/GreetingService.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/com/alibaba/dubbo/samples/api/GreetingsService.java) on GitHub.*
+*See [api/GreetingService.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/org/apache/dubbo/samples/api/GreetingsService.java) on GitHub.*
 
 ### Implement service interface for the provider
 
@@ -73,7 +73,7 @@ public class GreetingServiceImpl implements GreetingService {
 }
 ```
 
-*See [provider/GreetingServiceImpl.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/com/alibaba/dubbo/samples/server/GreetingsServiceImpl.java) on GitHub.*
+*See [provider/GreetingServiceImpl.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/org/apache/dubbo/samples/provider/GreetingsServiceImpl.java) on GitHub.*
 
 ### Start service provider
 
@@ -101,7 +101,7 @@ public class Application {
 }
 ```
 
-*See [provider/Application.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/com/alibaba/dubbo/samples/provider/Application.java) on GitHub.*
+*See [provider/Application.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/org/apache/dubbo/samples/provider/Application.java) on GitHub.*
 
 ### Build and run the provider
 
@@ -141,7 +141,7 @@ public class Application {
 
 The consumer will print out `Hello world` on the screen.
 
-*See [consumer/Application.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/com/alibaba/dubbo/samples/consumer/Application.java) on GitHub.*
+*See [consumer/Application.java](https://github.com/dubbo/dubbo-samples/blob/master/dubbo-samples-api/src/main/java/org/apache/dubbo/samples/consumer/Application.java) on GitHub.*
 
 ### Next steps
 

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/Router.java

@@ -51,4 +51,31 @@ public interface Router extends Comparable<Router> {
      */
     <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation invocation) throws RpcException;
 
+    /**
+     * priority
+     *
+     * @return
+     */
+    int getPriority();
+
+    /**
+     * compare Router
+     *
+     * @param o
+     * @return
+     */
+    @Override
+    default int compareTo(Router o) {
+        if (o == null) {
+            throw new IllegalArgumentException();
+        }
+        if (this.getPriority() == o.getPriority()) {
+            if (o.getUrl() == null) {
+                return -1;
+            }
+            return getUrl().toFullString().compareTo(o.getUrl().toFullString());
+        } else {
+            return getPriority() > o.getPriority() ? 1 : -1;
+        }
+    }
 }

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/loadbalance/RoundRobinLoadBalance.java

@@ -108,7 +108,6 @@ protected <T> Invoker<T> doSelect(List<Invoker<T>> invokers, URL url, Invocation
                 weightedRoundRobin = new WeightedRoundRobin();
                 weightedRoundRobin.setWeight(weight);
                 map.putIfAbsent(identifyString, weightedRoundRobin);
-                weightedRoundRobin = map.get(identifyString);
             }
             if (weight != weightedRoundRobin.getWeight()) {
                 //weight changed

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/router/MockInvokersSelector.java

@@ -49,6 +49,11 @@ public <T> List<Invoker<T>> route(final List<Invoker<T>> invokers,
         return invokers;
     }
 
+    @Override
+    public int getPriority() {
+        return Integer.MAX_VALUE;
+    }
+
     private <T> List<Invoker<T>> getMockedInvokers(final List<Invoker<T>> invokers) {
         if (!hasMockProviders(invokers)) {
             return null;

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/router/condition/ConditionRouter.java

@@ -40,7 +40,6 @@
 
 /**
  * ConditionRouter
- *
  */
 public class ConditionRouter implements Router {
 
@@ -178,17 +177,13 @@ public <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation
     }
 
     @Override
-    public URL getUrl() {
-        return url;
+    public int getPriority() {
+        return priority;
     }
 
     @Override
-    public int compareTo(Router o) {
-        if (o == null || o.getClass() != ConditionRouter.class) {
-            return 1;
-        }
-        ConditionRouter c = (ConditionRouter) o;
-        return this.priority == c.priority ? url.toFullString().compareTo(c.url.toFullString()) : (this.priority > c.priority ? 1 : -1);
+    public URL getUrl() {
+        return url;
     }
 
     boolean matchWhen(URL url, Invocation invocation) {

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/router/script/ScriptRouter.java

@@ -40,7 +40,6 @@
 
 /**
  * ScriptRouter
- *
  */
 public class ScriptRouter implements Router {
 
@@ -114,13 +113,24 @@ public <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation
         }
     }
 
+    @Override
+    public int getPriority() {
+        return priority;
+    }
+
     @Override
     public int compareTo(Router o) {
-        if (o == null || o.getClass() != ScriptRouter.class) {
-            return 1;
+        if (o == null) {
+            throw new IllegalArgumentException();
+        }
+        if (this.priority == o.getPriority()) {
+            if (o instanceof ScriptRouter) {
+                ScriptRouter c = (ScriptRouter) o;
+                return rule.compareTo(c.rule);
+            }
+            return 0;
+        } else {
+            return this.priority > o.getPriority() ? 1 : -1;
         }
-        ScriptRouter c = (ScriptRouter) o;
-        return this.priority == c.priority ? rule.compareTo(c.rule) : (this.priority > c.priority ? 1 : -1);
     }
-
 }

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/router/tag/TagRouter.java

@@ -72,18 +72,10 @@ public <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation
                         result.add(invoker);
                     }
                 }
-                // If no invoker be selected, downgrade to normal invokers
-                if (result.isEmpty()) {
-                    for (Invoker<T> invoker : invokers) {
-                        if (StringUtils.isEmpty(invoker.getUrl().getParameter(Constants.TAG_KEY))) {
-                            result.add(invoker);
-                        }
-                    }
-                }
-            // Normal request
-            } else {
+            }
+            // If Constants.REQUEST_TAG_KEY unspecified or no invoker be selected, downgrade to normal invokers
+            if (result.isEmpty()) {
                 for (Invoker<T> invoker : invokers) {
-                    // Can't access tag invoker,only normal invoker should be selected
                     if (StringUtils.isEmpty(invoker.getUrl().getParameter(Constants.TAG_KEY))) {
                         result.add(invoker);
                     }
@@ -98,11 +90,7 @@ public <T> List<Invoker<T>> route(List<Invoker<T>> invokers, URL url, Invocation
     }
 
     @Override
-    public int compareTo(Router o) {
-        if (o == null || o.getClass() != TagRouter.class) {
-            return 1;
-        }
-        TagRouter c = (TagRouter) o;
-        return this.priority == c.priority ? url.toFullString().compareTo(c.url.toFullString()) : (this.priority > c.priority ? 1 : -1);
+    public int getPriority() {
+        return priority;
     }
 }

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/support/AbstractClusterInvoker.java

@@ -24,6 +24,7 @@
 import org.apache.dubbo.common.logger.LoggerFactory;
 import org.apache.dubbo.common.utils.CollectionUtils;
 import org.apache.dubbo.common.utils.NetUtils;
+import org.apache.dubbo.common.utils.StringUtils;
 import org.apache.dubbo.rpc.Invocation;
 import org.apache.dubbo.rpc.Invoker;
 import org.apache.dubbo.rpc.Result;
@@ -44,8 +45,8 @@
  */
 public abstract class AbstractClusterInvoker<T> implements Invoker<T> {
 
-    private static final Logger logger = LoggerFactory
-            .getLogger(AbstractClusterInvoker.class);
+    private static final Logger logger = LoggerFactory.getLogger(AbstractClusterInvoker.class);
+
     protected final Directory<T> directory;
 
     protected final boolean availablecheck;
@@ -110,25 +111,28 @@ public void destroy() {
      * @return the invoker which will final to do invoke.
      * @throws RpcException
      */
-    protected Invoker<T> select(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
-        if (invokers == null || invokers.isEmpty()) {
+    protected Invoker<T> select(LoadBalance loadbalance, Invocation invocation,
+        List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
+
+        if (CollectionUtils.isEmpty(invokers)) {
             return null;
         }
-        String methodName = invocation == null ? "" : invocation.getMethodName();
+        String methodName = invocation == null ? StringUtils.EMPTY : invocation.getMethodName();
 
-        boolean sticky = invokers.get(0).getUrl().getMethodParameter(methodName, Constants.CLUSTER_STICKY_KEY, Constants.DEFAULT_CLUSTER_STICKY);
-        {
-            //ignore overloaded method
-            if (stickyInvoker != null && !invokers.contains(stickyInvoker)) {
-                stickyInvoker = null;
-            }
-            //ignore concurrency problem
-            if (sticky && stickyInvoker != null && (selected == null || !selected.contains(stickyInvoker))) {
-                if (availablecheck && stickyInvoker.isAvailable()) {
-                    return stickyInvoker;
-                }
+        boolean sticky = invokers.get(0).getUrl()
+            .getMethodParameter(methodName, Constants.CLUSTER_STICKY_KEY, Constants.DEFAULT_CLUSTER_STICKY);
+
+        //ignore overloaded method
+        if (stickyInvoker != null && !invokers.contains(stickyInvoker)) {
+            stickyInvoker = null;
+        }
+        //ignore concurrency problem
+        if (sticky && stickyInvoker != null && (selected == null || !selected.contains(stickyInvoker))) {
+            if (availablecheck && stickyInvoker.isAvailable()) {
+                return stickyInvoker;
             }
         }
+
         Invoker<T> invoker = doSelect(loadbalance, invocation, invokers, selected);
 
         if (sticky) {
@@ -137,8 +141,10 @@ protected Invoker<T> select(LoadBalance loadbalance, Invocation invocation, List
         return invoker;
     }
 
-    private Invoker<T> doSelect(LoadBalance loadbalance, Invocation invocation, List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
-        if (invokers == null || invokers.isEmpty()) {
+    private Invoker<T> doSelect(LoadBalance loadbalance, Invocation invocation,
+        List<Invoker<T>> invokers, List<Invoker<T>> selected) throws RpcException {
+
+        if (CollectionUtils.isEmpty(invokers)) {
             return null;
         }
         if (invokers.size() == 1) {
@@ -158,7 +164,7 @@ private Invoker<T> doSelect(LoadBalance loadbalance, Invocation invocation, List
                     int index = invokers.indexOf(invoker);
                     try {
                         //Avoid collision
-                        invoker = index < invokers.size() - 1 ? invokers.get(index + 1) : invokers.get(0);
+                        invoker = invokers.get((index + 1) % invokers.size());
                     } catch (Exception e) {
                         logger.warn(e.getMessage() + " may because invokers list dynamic change, ignore.", e);
                     }
@@ -171,7 +177,8 @@ private Invoker<T> doSelect(LoadBalance loadbalance, Invocation invocation, List
     }
 
     /**
-     * Reselect, use invokers not in `selected` first, if all invokers are in `selected`, just pick an available one using loadbalance policy.
+     * Reselect, use invokers not in `selected` first, if all invokers are in `selected`,
+     * just pick an available one using loadbalance policy.
      *
      * @param loadbalance
      * @param invocation
@@ -181,48 +188,40 @@ private Invoker<T> doSelect(LoadBalance loadbalance, Invocation invocation, List
      * @throws RpcException
      */
     private Invoker<T> reselect(LoadBalance loadbalance, Invocation invocation,
-                                List<Invoker<T>> invokers, List<Invoker<T>> selected, boolean availablecheck)
-            throws RpcException {
+        List<Invoker<T>> invokers, List<Invoker<T>> selected, boolean availablecheck) throws RpcException {
 
         //Allocating one in advance, this list is certain to be used.
-        List<Invoker<T>> reselectInvokers = new ArrayList<Invoker<T>>(invokers.size() > 1 ? (invokers.size() - 1) : invokers.size());
-
-        //First, try picking a invoker not in `selected`.
-        if (availablecheck) { // invoker.isAvailable() should be checked
-            for (Invoker<T> invoker : invokers) {
-                if (invoker.isAvailable()) {
-                    if (selected == null || !selected.contains(invoker)) {
-                        reselectInvokers.add(invoker);
-                    }
-                }
-            }
-            if (!reselectInvokers.isEmpty()) {
-                return loadbalance.select(reselectInvokers, getUrl(), invocation);
-            }
-        } else { // do not check invoker.isAvailable()
-            for (Invoker<T> invoker : invokers) {
-                if (selected == null || !selected.contains(invoker)) {
-                    reselectInvokers.add(invoker);
-                }
+        List<Invoker<T>> reselectInvokers = new ArrayList<>(
+            invokers.size() > 1 ? (invokers.size() - 1) : invokers.size());
+
+        // First, try picking a invoker not in `selected`.
+        for (Invoker<T> invoker : invokers) {
+            if (availablecheck && !invoker.isAvailable()) {
+                continue;
             }
-            if (!reselectInvokers.isEmpty()) {
-                return loadbalance.select(reselectInvokers, getUrl(), invocation);
+
+            if (selected == null || !selected.contains(invoker)) {
+                reselectInvokers.add(invoker);
             }
         }
+
+        if (!reselectInvokers.isEmpty()) {
+            return loadbalance.select(reselectInvokers, getUrl(), invocation);
+        }
+
         // Just pick an available invoker using loadbalance policy
-        {
-            if (selected != null) {
-                for (Invoker<T> invoker : selected) {
-                    if ((invoker.isAvailable()) // available first
-                            && !reselectInvokers.contains(invoker)) {
-                        reselectInvokers.add(invoker);
-                    }
+        if (selected != null) {
+            for (Invoker<T> invoker : selected) {
+                if ((invoker.isAvailable()) // available first
+                        && !reselectInvokers.contains(invoker)) {
+                    reselectInvokers.add(invoker);
                 }
             }
-            if (!reselectInvokers.isEmpty()) {
-                return loadbalance.select(reselectInvokers, getUrl(), invocation);
-            }
         }
+        if (!reselectInvokers.isEmpty()) {
+            return loadbalance.select(reselectInvokers, getUrl(), invocation);
+        }
+
         return null;
     }
 
@@ -257,7 +256,7 @@ public String toString() {
     }
 
     protected void checkInvokers(List<Invoker<T>> invokers, Invocation invocation) {
-        if (invokers == null || invokers.isEmpty()) {
+        if (CollectionUtils.isEmpty(invokers)) {
             throw new RpcException("Failed to invoke the method "
                     + invocation.getMethodName() + " in the service " + getInterface().getName()
                     + ". No provider available for the service " + directory.getUrl().getServiceKey()

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/support/FailbackClusterInvoker.java

@@ -65,7 +65,7 @@ public FailbackClusterInvoker(Directory<T> directory) {
         super(directory);
     }
 
-    private void addFailed(Invocation invocation, AbstractClusterInvoker<?> router) {
+    private void addFailed(Invocation invocation, AbstractClusterInvoker<?> invoker) {
         if (retryFuture == null) {
             synchronized (this) {
                 if (retryFuture == null) {
@@ -84,11 +84,11 @@ public void run() {
                 }
             }
         }
-        failed.put(invocation, router);
+        failed.put(invocation, invoker);
     }
 
     void retryFailed() {
-        if (failed.size() == 0) {
+        if (failed.isEmpty()) {
             return;
         }
         for (Map.Entry<Invocation, AbstractClusterInvoker<?>> entry : new HashMap<>(failed).entrySet()) {