enhance application discovery toString (#12953)

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/directory/AbstractDirectory.java

@@ -224,10 +224,8 @@ public abstract class AbstractDirectory<T> implements Directory<T> {
 
                 logger.warn(CLUSTER_NO_VALID_PROVIDER, "provider server or registry center crashed", "",
                     "No provider available after connectivity filter for the service " + getConsumerUrl().getServiceKey()
-                        + " All validInvokers' size: " + validInvokers.size()
                         + " All routed invokers' size: " + routedResult.size()
-                        + " All invokers' size: " + invokers.size()
-                        + " from registry " + getUrl().getAddress()
+                        + " from registry " + this
                         + " on the consumer " + NetUtils.getLocalHost()
                         + " using the dubbo version " + Version.getVersion() + ".");
             }

dubbo-registry/dubbo-registry-api/src/main/java/org/apache/dubbo/registry/client/ServiceDiscoveryRegistry.java

@@ -133,10 +133,8 @@ public class ServiceDiscoveryRegistry extends FailbackRegistry {
 
         boolean should = PROVIDER_SIDE.equals(side); // Only register the Provider.
 
-        if (!should) {
-            if (logger.isDebugEnabled()) {
-                logger.debug(String.format("The URL[%s] should not be registered.", providerURL));
-            }
+        if (!should && logger.isDebugEnabled()) {
+            logger.debug(String.format("The URL[%s] should not be registered.", providerURL));
         }
 
         if (!acceptable(providerURL)) {
@@ -394,7 +392,7 @@ public class ServiceDiscoveryRegistry extends FailbackRegistry {
             Lock mappingLock = serviceNameMapping.getMappingLock(event.getServiceKey());
             try {
                 mappingLock.lock();
-                if (CollectionUtils.isEmpty(tempOldApps) && newApps.size() > 0) {
+                if (CollectionUtils.isEmpty(tempOldApps) && !newApps.isEmpty()) {
                     serviceNameMapping.putCachedMapping(ServiceNameMapping.buildMappingKey(url), newApps);
                     subscribeURLs(url, listener, newApps);
                     oldApps = newApps;

dubbo-registry/dubbo-registry-api/src/main/java/org/apache/dubbo/registry/client/ServiceDiscoveryRegistryDirectory.java

@@ -584,7 +584,7 @@ public class ServiceDiscoveryRegistryDirectory<T> extends DynamicDirectory<T> {
         }
 
         void addNotifyListener(ServiceDiscoveryRegistryDirectory<?> listener) {
-            if (listeners.size() == 0) {
+            if (listeners.isEmpty()) {
                 this.initWith(moduleModel.getApplicationModel().getApplicationName() + CONFIGURATORS_SUFFIX);
             }
             this.listeners.add(listener);
@@ -592,7 +592,7 @@ public class ServiceDiscoveryRegistryDirectory<T> extends DynamicDirectory<T> {
 
         void removeNotifyListener(ServiceDiscoveryRegistryDirectory<?> listener) {
             this.listeners.remove(listener);
-            if (listeners.size() == 0) {
+            if (listeners.isEmpty()) {
                 this.stopListen(moduleModel.getApplicationModel().getApplicationName() + CONFIGURATORS_SUFFIX);
             }
         }
@@ -693,4 +693,12 @@ public class ServiceDiscoveryRegistryDirectory<T> extends DynamicDirectory<T> {
         }
     }
 
+    @Override
+    public String toString() {
+        return "ServiceDiscoveryRegistryDirectory(" +
+            "registry: " + getUrl().getAddress() +
+            ", subscribed key: " + (serviceListener == null || CollectionUtils.isEmpty(serviceListener.getServiceNames())
+            ? getConsumerUrl().getServiceKey() : serviceListener.getServiceNames().toString()) +
+            ")-" + super.toString();
+    }
 }

dubbo-registry/dubbo-registry-api/src/main/java/org/apache/dubbo/registry/integration/DynamicDirectory.java

@@ -195,7 +195,7 @@ public abstract class DynamicDirectory<T> extends AbstractDirectory<T> implement
         if (forbidden && shouldFailFast) {
             // 1. No service provider 2. Service providers are disabled
             throw new RpcException(RpcException.FORBIDDEN_EXCEPTION, "No provider available from registry " +
-                getUrl().getAddress() + " for service " + getConsumerUrl().getServiceKey() + " on consumer " +
+                this + " for service " + getConsumerUrl().getServiceKey() + " on consumer " +
                 NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() +
                 ", please check status of providers(disabled, not registered or in blacklist).");
         }