beautify code

rpc-framework-common/src/main/java/github/javaguide/extension/ExtensionLoader.java

 package github.javaguide.extension;
 
+import github.javaguide.utils.StringUtils;
 import lombok.extern.slf4j.Slf4j;
 
 import java.io.BufferedReader;
@@ -51,7 +52,7 @@ public final class ExtensionLoader<T> {
     }
 
     public T getExtension(String name) {
-        if (name == null || name.isEmpty()) {
+        if (StringUtils.isBlank(name)) {
             throw new IllegalArgumentException("Extension name should not be null or empty.");
         }
         // firstly get from cache, if not hit, create one

rpc-framework-common/src/main/java/github/javaguide/utils/CollectionUtils.java

+package github.javaguide.utils;
+
+import java.util.Collection;
+
+/**
+ * @Description:
+ * @Author: zhanghua
+ * @Date: 2022/3/6 12:58 上午
+ */
+public class CollectionUtils {
+
+	public static boolean isEmpty(Collection coll) {
+		return coll == null || coll.isEmpty();
+	}
+
+	public static boolean isNotEmpty(Collection coll) {
+		return isEmpty(coll);
+	}
+}

rpc-framework-common/src/main/java/github/javaguide/utils/StringUtils.java

+package github.javaguide.utils;
+
+/**
+ * @Description:
+ * @Author: zhanghua
+ * @Date: 2022/3/6 12:58 上午
+ */
+public class StringUtils {
+
+	public static boolean isBlank(String s){
+		int strLen ;
+		if(s == null || (strLen = s.length()) == 0){
+			return true;
+		}
+		for(int i = 0; i < strLen; ++i) {
+			if (!Character.isWhitespace(s.charAt(i))) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	public static boolean isNotBlank(String s){
+		return !isBlank(s);
+	}
+
+}

rpc-framework-simple/src/main/java/github/javaguide/loadbalance/AbstractLoadBalance.java

 package github.javaguide.loadbalance;
 
 import github.javaguide.remoting.dto.RpcRequest;
+import github.javaguide.utils.CollectionUtils;
 
 import java.util.List;
 
@@ -13,7 +14,7 @@ import java.util.List;
 public abstract class AbstractLoadBalance implements LoadBalance {
     @Override
     public String selectServiceAddress(List<String> serviceAddresses, RpcRequest rpcRequest) {
-        if (serviceAddresses == null || serviceAddresses.size() == 0) {
+        if (CollectionUtils.isEmpty(serviceAddresses)) {
             return null;
         }
         if (serviceAddresses.size() == 1) {

rpc-framework-simple/src/main/java/github/javaguide/loadbalance/LoadBalance.java

@@ -16,8 +16,9 @@ public interface LoadBalance {
     /**
      * Choose one from the list of existing service addresses list
      *
-     * @param serviceAddresses Service address list
+     * @param serviceUrlList Service address list
+     * @param rpcRequest
      * @return target service address
      */
-    String selectServiceAddress(List<String> serviceAddresses, RpcRequest rpcRequest);
+    String selectServiceAddress(List<String> serviceUrlList, RpcRequest rpcRequest);
 }

rpc-framework-simple/src/main/java/github/javaguide/registry/zk/ZkServiceDiscoveryImpl.java

@@ -7,6 +7,7 @@ import github.javaguide.loadbalance.LoadBalance;
 import github.javaguide.registry.ServiceDiscovery;
 import github.javaguide.registry.zk.util.CuratorUtils;
 import github.javaguide.remoting.dto.RpcRequest;
+import github.javaguide.utils.CollectionUtils;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.curator.framework.CuratorFramework;
 
@@ -32,7 +33,7 @@ public class ZkServiceDiscoveryImpl implements ServiceDiscovery {
         String rpcServiceName = rpcRequest.getRpcServiceName();
         CuratorFramework zkClient = CuratorUtils.getZkClient();
         List<String> serviceUrlList = CuratorUtils.getChildrenNodes(zkClient, rpcServiceName);
-        if (serviceUrlList == null || serviceUrlList.size() == 0) {
+        if (CollectionUtils.isEmpty(serviceUrlList)) {
             throw new RpcException(RpcErrorMessageEnum.SERVICE_CAN_NOT_BE_FOUND, rpcServiceName);
         }
         // load balancing